the concentrations of bile acids and erythropoietin in pregnant

Transkrypt

Developmental Period Medicine, 2013, XVII, 3
232
© IMiD, Wydawnictwo Aluna
Aneta Kowalska-Kańka, Tomasz Maciejewski, Krzysztof Tomasz Niemiec
THE CONCENTRATIONS OF BILE ACIDS
AND ERYTHROPOIETIN IN PREGNANT WOMEN
WITH INTRAHEPATIC CHOLESTASIS
AND THE STATE OF THE FETUS AND NEWBORN*
STĘŻENIA KWASÓW ŻÓŁCIOWYCH I ERYTROPOETYNY
U CIĘŻARNYCH Z CHOLESTAZĄ WEWNĄTRZWĄTROBOWĄ
A STAN PŁODU I NOWORODKA
Department of Obstetrics and Gynaecology,
Institute of Mother and Child, Warsaw, Poland,
Abstract
Intrahepatic cholestasis of pregnancy (ICP) is not a common complication of pregnancy, but may
be a threat to fetal condition. The elevated level of bile acids defines ICP and determines its severity.
Indicators of hepatocyte damage during ICP are elevated ALT and AST. The fetal condition in the ICP
depends on the degree of liver damage. The most common complication is preterm delivery, but the
risk of fetal death is currently around 3.5%. Erythropoietin is a peptide hormone produced mostly in
the kidneys and liver due to tissue hypoxia. EPO concentration in the blood serum of pregnant women
increases, because of its production in the placenta. Reducing the blood flow through the fetal-placental
unit is the cause of fetal complications associated with ICP. The reason for blood flow the decrease is
elevated TBA concentration. The hypothesis of the study assumed that in the course of ICP, elevated bile
acids reduce blood flow through the fetal-placental unit, which causes placental hypoxia, and which can
lead to the increased secretion of EPO in the placenta.
The aim of this study was to find a correlation between high levels of bile acids and concetration of
erythropoietin in the serum of women with ICP without anemia and renal dysfunction and to evaluate
the course and outcome of pregnancy in women with ICP.
Material and methods: 73 pregnant women from the Department of Obstetrics and Gynaecology,
Institute of Mother and Child in Warsaw, were included in the study. 33 pregnant women with ICP were
included in group I. Group II (control) consisted of 40 women with pregnancy without ICP. The inclusion
criteria for the study in group I were as follows: TBA≥11 μmol/l; elevated liver enzymes: ALT>41 U/l and/
or AST>40 U/l; and the presence of pruritus (current or history). The exclusion criteria included: anemia
(HGB<11 g/dl); viral hepatitis A, B, C; other abnormalities of the liver and of the biliary tract; alcohol and
drug addiction; HIV infection; diseases of skin with itching and rash; acute and chronic kidney disease;
bone disease; acute and chronic bleeding in pregnancy and preeclampsia. Laboratory analysis of the
parameters of liver function, kidney function and blood counts was performed on the same day as the
TBA and EPO concentration. The intensity of pruritus in patients with ICP was determined on the basis
of a special 5-degree scale, proposed by the author. The conditions of fetuses were monitored during
laboratory tests of the pregnant women and delivery with cardiotocography and ultrasound. Analysis of
the newborns was based on the following data: gestational age at delivery, birth weight, 1-minute and
5-minute Apgar scores, blood gas parameters in the umbilical artery. The statistical analysis of clinical
and laboratory parameters was performed using Statistica 5.5 PL package. The results were analyzed in
order to find significant differences between them.
Results: In the group of pregnant women with ICP mean gestational age at delivery was 35.97±1.86
weeks, in the control group 38.1±1.46 weeks (p<0.05). The percentage of preterm births (<37 weeks) in
group I was 45.5%, in group II 15% (p<0.05). At the time of delivery in group I fetal hypoxia symptoms
*The publication contains extensive fragments of doctoral thesis
The concentrations of bile acids and erythropoietin in pregnant women with intrahepatic cholestasis
233
were observed in 9.8% of fetuses vs 17.4% in group II (p=ns.). In the group of women with ICP 36.6% of
newborns had low birth weight (less than 2500 g), including 2.4% of extremely low birth weight (<1000
g). In group II, the percentage of infants with low birth weight was 10.9% (p<0.05). The average 1-minute
and 5-minute Apgar scores were lower in group I compared to group II (p<0.05). The average TBA
concentration was 22.82±14.78 µmol/L in group I vs 2.43±2.04 µmol/L in group II (p<0.05). The obtained
data show that the intensity of pruritus was not directly related to the concentration of bile acids.
The activity of liver enzymes in the group of women with ICP was significantly increased compared to
controls. There were no cases of jaundice among the women examined. Among coagulation parameters
in group I, significantly elevated concentration of fibrinogen (p<0,05) was found. Differences in the
values of selected markers of renal function (urea, creatinine) and hematological parameters were not
statistically significant. Erythropoietin concentrations in both groups were similar. In group I the mean
value was 17.35±8.86 mU/ml and in the control group 18.12±9.48 mU/ml (p>0.05).
Conclusions: In the group of pregnant women with ICP there was no correlation between the concentration
of bile acids and erythropoietin. Preterm delivery and worse neonatal outcome were more common in the
ICP group, which indicates that perinatal care should be improved and further studies are needed.
Key words: intrahepatic cholestasis of pregnancy, erythropoietin, preterm delivery, fetal hypoxia
Streszczenie
Wewnątrzwątrobowa cholestaza ciężarnych (ICP) nie jest częstym powikłaniem ciąży, ale stanowi
zagrożenie dla dobrostanu płodu. Podwyższone stężenie kwasów żółciowych definiuje cholestazę
ciężarnych i determinuje jej nasilenie. W przebiegu ICP wskaźnikami uszkodzenia hepatocytów są
podwyższone aktywności ALT i AST. Stan płodu ciężarnej z ICP zależny jest od stopnia uszkodzenia
wątroby. Najczęstszym powikłaniem położniczym u ciężarnych z cholestazą jest poród przedwczesny.
Erytropoetyna (EPO) jest hormonem peptydowym wydzielanym głównie przez nerki i wątrobę. Synteza EPO stymulowana jest przez hipoksję tkankową. Pulę EPO w surowicy krwi ciężarnej zwiększa jej
synteza w łożysku. Zmniejszenie przepływu łożyskowego jest postulowane jako przyczyna wystąpienia
powikłań płodowych związanych z ICP. Za czynnik sprawczy uznaje się podwyższone stężenie kwasów
żółciowych.
Hipoteza pracy zakładała, że w przebiegu ICP podwyższone stężenie kwasów żółciowych powoduje
zmniejszenie przepływu krwi przez jednostkę płodowo-łożyskową, wywołując hipoksję łożyska, co może
w konsekwencji doprowadzić do wzmożonej sekrecji EPO w łożysku.
Celem pracy było szukanie korelacji między stężeniami kwasów żółciowych a stężeniem EPO w surowicy
krwi kobiet z ICP bez towarzyszącej niedokrwistości i chorób nerek, a także ocena przebiegu ciąży i stanu
noworodków u kobiet z ICP.
Materiał i metody: Badaniem objęto 73 ciężarne będące pacjentkami Kliniki Położnictwa i Ginekologii
Instytutu Matki i Dziecka w Warszawie. Grupę I stanowiły 33 ciężarne z ICP. Do grupy II (kontrolnej) weszło
40 ciężarnych bez ICP. Kryteriami włączenia pacjentek do grupy I były: TBA≥11 μmol/l, podwyższona
aktywność enzymów wątrobowych: ALT>41 U/l i/lub AST>40 U/l, a także obecność świądu skóry (aktualnie lub w wywiadzie). Kryteria wyłączenia pacjentek z badania obejmowały: niedokrwistość
(HGB<11 g/dl); wirusowe zapalenia wątroby typu A, B, C; kamica pęcherzyka i dróg żółciowych; inne patologie wątroby i dróg żółciowych przebiegające z zastojem żółci; choroba alkoholowa; zakażenie HIV;
uzależnienie od substancji psychoaktywnych; choroby skóry przebiegające ze świądem i wysypką; ostre
i przewlekłe choroby nerek upośledzające ich wydolność; choroby szpiku; ostre i przewlekłe krwawienia
w ciąży; stan przedrzucawkowy.
Laboratoryjną analizę parametrów funkcji wątroby, nerek i morfologii krwi badanych pacjentek
wykonywano w dniu oznaczenia całkowitego stężenia kwasów żółciowych i erytropoetyny. Natężenie
świądu pacjentek z ICP określano na podstawie zaproponowanej pięciostopniowej skali. Dobrostan
płodów kobiet ciężarnych włączonych do badania monitorowano w czasie wykonywania zaplanowanych oznaczeń laboratoryjnych i w czasie porodu przy pomocy zapisów kardiotokograficznych i badań
ultrasonograficznych. Analiza stanu urodzeniowego dzieci kobiet włączonych do badania opierała się
o następujące dane: wiek ciążowy w czasie porodu; masa urodzeniowa; punktacja Apgar w 1-szej, i 5-tej
minucie życia; ocena parametrów gazometrycznych krwi z tętnicy pępowinowej. Analizę statystyczną
badanych parametrów laboratoryjnych i klinicznych wykonano stosując pakiet Statistica 5.5 PL. Otrzymane wyniki analizowano w celu oceny statystycznie istotnych różnic pomiędzy nimi.
Wyniki: W grupie kobiet z cholestazą ciężarnych średni wiek ciążowy w momencie porodu wynosił
35,97±1,86 tyg., w grupie kontrolnej 38,1±1,46 tyg (p<0,05). Odsetek porodów przedwczesnych (<37 tyg.
ciąży) w grupie I wynosił 45,5%, a w grupie II 15% (p<0,05). W czasie porodu w grupie I cechy zagrażającej
zamartwicy wewnątrzmacicznej zaobserwowano u 9,8% płodów vs 17,4% w grupie II (p=ns.). W grupie
Aneta Kowalska-Kańka i wsp.
234
kobiet z ICP 36,6% noworodków urodziło się z małą masą ciała (poniżej 2500 g), w tym 2,4% ze skrajnie
małą masą urodzeniową (<1000 g). W grupie II odsetek dzieci z małą masą urodzeniową wyniósł 10,9%
(p<0,05). Punktacja w skali Apgar zarówno w 1-szej, jak i 5-tej minucie życia była niższa w grupie I w stosunku do grupy II (p<0,05).
Średnie stężenie kwasów żółciowych w grupie I wyniosło 22,82±14,78 µmol/L vs 2,43±2,04 µmol/L
w grupie II (p<0,05). Natężenie świądu skóry w dniu wykonywania analiz nie miało bezpośredniego
związku z oznaczonym tego dnia stężeniem kwasów żółciowych. W grupie kobiet z cholestazą,
Aktywności AST i ALT była istotnie statystycznie podwyższona w grupie I w stosunku do grupy II. Nie
stwierdzono przypadków wystąpienia żółtaczki wśród badanych kobiet. Oceniając układ krzepnięcia
stwierdzono w grupie I znamiennie podwyższone stężeniem fibrynogenu (p<0,05). Różnice wartości
średnich wybranych wykładników funkcji nerek (mocznik, kreatynina) oraz badanych parametrów hematologicznych w obu grupach badanych nie były istotne statystycznie. Stężenia erytropoetyny w obu
grupach były zbliżone. Wśród ciężarnych z cholestazą wartość średnia wyniosła 17,35±8,86 mU/ml, zaś
w grupie kontrolnej 18,12±9,48 mU/ml (p>0,05).
Wnioski: W grupie ciężarnych z ICP nie stwierdzono zależności między stężeniem kwasów żółciowych
i erytropoetyny w surowicy krwi, natomiast stwierdzono statystycznie istotnie częstsze występowanie
porodu przedwczesnego oraz gorszy stan urodzeniowy noworodków. Wskazuje to na konieczność poprawy opieki perinatalnej oraz dalszego prowadzenia badań w tym zakresie.
Słowa kluczowe: wewnątrzwątrobowa cholestaza ciężarnych, erytropoetyna, poród przedwczesny,
niedotlenienie płodu
DEV. PERIOD MED., 2013, XVII, 3, 232245
INTRODUCTION
Intrahepatic cholestasis of pregnancy (ICP) is
a pregnancy complication that typically develops in its
second or third trimester. The etymology of ICP is diverse
and affected by multiple factors. The mechanism of its
origin has not been fully recognized. Family history of
ICP, its potential recurrence in the following pregnancy,
as well as the presence of morbidity in endemic areas,
suggest genetic predisposition. The Genetic background
of ICP seems to be multigenic in character (1). Extensive
research has been performed in the field of bile transport
proteins (ABCB4, ABCB11 i ATP8B1) (2, 3).
According to some authors ICP can be considered an
obstetric endocrinopathy. The more frequent occurance of
cholestasis in multiple pregnancies (20% to 22%) can be
indicative of the role of hormonal factors in its etiopathogenesis
(4, 5). ICP typically occurs in the third trimester of pregnancy,
when estrogen and progesterone concentrations are the
highest (1). The fact that the liver parameter normalization
takes place after delivery, also adds to the hormonal background
of ICP development (6).
A significant role in ICP development is played
by progesterone metabolites (7, 8). In animal models
sulphated progesterone metabolites and estrogen
glucuronide metabolites, besides impeding the activity
of bile acid transport pump, cripple mitochondrial
activity, which fosters intracellular accumulation of
toxic bile acids (9, 10).
Risk factors of ICP also include: coexisting liver and
biliary tract conditions, older patient’s age (> 35 years
old), hyperemesis gravidarum. The occurrence of ICP
is even 5 times more common in multiple pregnancies
(5, 11, 12).
The most frequent complaint reported by pregnant
patients affected by ICP is pruritus. It occurs in approximately
25% of women, typically in the second or third trimester
and recedes within 48 hours of delivery (1, 13). Its intensity
is variable (14, 15). It is also not expressly linked to the
extent of liver dysfunction (1). Jaundice occurs in ICP
in 10% to 15% of patients (1).
In the majority of women cholestasis recurs in subsequent
pregnancies (60-70% of recurrence risk) (30), however
the course of the condition in the previous pregnancy is
not indicative of ICP intensity in the following pregnancy
(1). There are also reports of the coexistence of ICP with
other pregnancy – related diseases: preeclempsia (16),
maternal acute fatty liver of pregnancy (17), as well as
gestational diabetes (18).
It is commonly recognized that the fetal condition
is associated with the extent of total serum bile acid
elevation in pregnancy and severity of hepatocyte damage
(1, 5, 19, 20). The Swedish scientist Anna Glantz found
that the risk of fetal hypoxia, appearance of meconium
in amniotic fluid or preterm delivery increases by 1-2%
for each additional μmol/L of bile acids (21).
The most frequent ICP complication is preterm delivery.
The average number of cases it occurs in is 30-40% (1,
22). The risk of preterm delivery is significantly higher
for TBA>40 μmol/L (21, 23). The mechanism of preterm
labor is not completely clear. It was found that cholalic
acid activity results in increased sensitivity of uterine
muscle to oxytocin and in the increased oxytocin receptor
expression (24).
Studies performed in the 1970s indicated that ICP
patients displayed significantly (10-15%) more common
intrauterine fetal death incidence (25). Currently, as a result
of the active management model, the death rate dropped
to 3.5% (1, 22). Fetal death risk is affected by bile acid
concentrations (1, 21). In an in vitro model reduced placental
blood circulation was observed that resulted from the
vasoconstrictory effect of cholalic acid and deoxycholic
acid on venous vessels of placental villi (26). Taurocholic
acid was also found to cripple contractility and to have
arythmogenic effect on cardiac muscle cells (11, 27). The
increased activity of apoptosis in the placenta and fetal
liver is also considered a potential etiologic factor of fetal
death in the case of ICP (6).
In the course of ICP, the abnormal cardiotocography
(CTG) pattern is observed. It pertains both to CTG records
during pregnancy, as well as to perinatal monitoring
of fetal well-being (1). The following abnormalities are
observed: tachycardia (>160 fetal heart rate/minute),
bradycardia (<100 fetal heart rate/minute) and narrow
oscillation of the fetal heart rate (1, 28).
As the normal pregnancy progresses, a minimum
increase in total bile acids is observed (1). In the third
trimester the level typically considered indicative of
cholestasis of pregnancy is TBA>11 μmol/l (7). Increased
maternal total bile acids lead to elevated TBA in fetal
circulation and reverse the bile acid transplacental gradient
(1, 8). The measurement of bile acid concentration is the
basic test aiming at diagnosis and therapy monitoring
of the cholestasis of pregnancy (1).
In the course of ICP, increased activity of AST and ALT
can precede the occurence of elevated TBA, however the
association between TBA level and liver transaminases
is not evident (13, 27). In most cases of ICP bilirubin
concentration is normal (1, 13). The majority of available
sources did not report abnormalities in coagulation
parameters (29).
The adopted perinatal care model and conventional
pharmacological treatment aim to minimize the risk
of serious fetal complications in the form of preterm
delivery, intrauterine asphyxia and fetal death. There
are, however, no uniform guidelines regarding the time
and the method of ending a pregnancy complicated by
cholestasis. In most British hospitals, as well as in Poland,
an active management of term pregnancies complicated
by ICP has been adopted (30). Assuming the risk of
intrauterine fetal death is increased at the end of the
pregnancy, labor in ICP patients is induced after 37
weeks of gestation (1, 2).
In pharmacological treatment of the intrahepatic
cholestasis of the pregnancy the key role is played by
ursodeoxycholic acid (UDCA) (1, 2, 15, 27, 31). In general
three core mechanisms of UDCA activity can be indicated
with regard to the neutralization of the disadvantageous
effect of endogenous bile acids: cytoprotective activity
against cholangiocytes, the protective effect on hepatocytes
and reduced serum concentration of endogenous toxic
bile acids (2, 13). Studies on ICP therapeutical use of
dexamethason and S-adenosyl-L-methionine (SAMe)
have been described in literature. In comparison to UDCA
these therapies have not resulted in better outcomes
with regard to the reduction of laboratory parameters
and clinical signs of cholestasis (2, 28, 32).
In available literature few papers were devoted to
the role of erythropoietin secretion in the course of
235
pregnancy. The publications usually focus on the problem
of anemia in pregnancy, as well as pregnancy – related
renal dysfunctions progressing to renal failure. Detailed
data on the structure, biological role, secretion regulation
of erythropoietin in normal and complicated pregnancy,
as well as the role of EPO in fetal well-being evaluation
were discussed in a separate publication of the same
authors in Developmental Period Medicine (33).
Taking into account the role ascribed to erythropoietin
in the evaluation of tissue hypoxia, the authors assumed that
in the course of the cholestasis of pregnancy the elevated
bile acid concentration causes reduced blood flow through
fetal – placental unit, which may further lead to placental
hypoxia. This, in turn, as a consequence of local hypoxia, leads
to increased erythropoietin secretion in the placenta.
The aim of the paper was to:
1. Search for an association between high bile acid
concentrations and the level of erythropoietin in maternal
serum of women with intrahepatic cholestasis of pregnancy,
without coexisting anemia or renal dysfunction.
2. Evaluate the course of pregnancy in women with
cholestasis of pregnancy and the fetal condition.
MATERIAL AND METHODS
73 pregnant women from the Department of Obstetrics
and Gynaecology, Institute of Mother and Child in
Warsaw, were included in the study. The women had
been patients of the Institute from March 2009 until the
end of September 2011. 33 pregnant women with ICP
were included in group I. Group II (control) consisted
of 40 pregnant women admitted to clinical hospital due
to labor or the course of pregnancy, with fetal well-being
confirmed based on analyses performed.
Pregnant women in group I were 21-42 years old with
the average age 32.91±4.4 years. 76% of pregnancies (25
cases) were single, 24% of pregnancies (8) were twin
pregnancies. 48.5% of patients (16) were primigravidas,
while 51.5% (17) of the women were multigravidas. In
group II the age of patients included in the study ranged
from 20 to 40 with average age 31.2±4.93 years. 85% (34)
were singular pregnancies. Twin pregnancies accounted
for 15% (6). 60% (24) of women were primigravidas,
40% (16) were multigravidas.
The inclusion criteria for the study in group I were as
follows: TBA≥11 μmol/l; elevated liver enzymes: ALT>41
U/l and/or AST>40 U/l; and the presence of pruritus
(current or history).
The exclusion criteria included: anemia (according to
WHO: HGB<11 g/dl); viral hepatitis A, B, C; cholecystolithiasis,
bile duct lithiasis, other abnormalities of the liver and the
biliary tract with coexisting cholestasis; alcohol addiction;
HIV infection; psychoactive substance abuse, diseases of
the skin with itching and rash; acute and chronic kidney
disease with impaired renal function; bone disease; acute
and chronic bleeding in pregnancy and preeclampsia.
All the patients included in the study have expressed
a written consent to participate in the research project
on a dedicated Conscious Consent Form. The Bioethics
Committee of the Institute of Mother and Child has
agreed to perform the study.
236
Laboratory methods
Sta!s!cal methods
Laboratory analysis of the parameters of liver function,
kidney function and blood counts was performed on
the same day as TBA and EPO concentration. An
ultrasound and CTG at rest were performed in patients
at the time.
Serum total bile acids were determined using the
Randox Bile Acid Kit method and reagent.
Blood serum erythropoietin concentration was measured
by the ELISA immunoenzymatic test using specific
monoclonal antibodies, with the help of ready-to-use
DRG EPO ELISA kits.
The following parameters of liver functions were
evaluated: liver enzyme, activity: alanine aminotransferase
(ALT) and aspartate aminotransferase (AST); total bilirubin;
coagulogram parameters (prothrombin time PT – INR,
Activated Partial Thromboplastin Time APTT, fibrinogen
level, D-dimer concentrations).
Renal function parameters were evaluated based on
blood serum concentration of urea and creatinine.
Selected parameters of blood count were also
analysed: red blood cells RBC, hematocrit (HCT)
level, hemoglobin (HGB) count and platelet (PLT)
count.
Patient data and the results obtained were entered
into a spreadsheet of the OpenOffice.org Calc 3.1.1
program. The statistical analysis of selected laboratory
and clinical parameters was performed with the use of
statistical modules of Statistica 5.5 PL package: Analysis
of Variance (ANOVA) test, Fisher’s exact test and KruskalWallis ANOVA test by ranks.
Fetal and newborn evalua!on methods
While the scheduled laboratory tests were performed,
fetal well-being was monitored with the help of
cardiotocography (CTG) records at rest. Intrapartum
fetal surveillance by CTG also took place.
The patients were also subject to ultrasound evaluation
of fetal venous flow. Fetal anatomy was analysed, and
the following parameters were determined: estimated
fetal weight (EFW) (according to Hadlock et al.), the
number of umbilical vessels, amniotic fluid volume
using Amniotic Fluid Index (AFI) or Maximal Vertical
Pocket (MVP), placental location and maturity according
to Grannum’s classification.
Umbilical artery (UA), umbilical vein (UV) and
middle cerebral artery (MCA) flow spectrum evaluation
was performed with the use of colour Doppler imaging.
By analysing the shape of flow waves in the vessels
evaluated, resistance index (RI) and pulsatility index
(PI), cerebral – umbilical ratio CPA (PI MCA / PI UA)
were counted.
Neonatal outcome evaluation was based on the following
data: gestational age at delivery; birth weight; 1-minute
and 5-minute Apgar scores; blood gas parameters in
the umbilical artery: pH, pCO2, pO2, base deficit/base
excess (BE).
Pruritus intensity in patients with ICP was determined
based on a 5-degree scale proposed by the authors.
The survey with the scale below was completed by
pregnant women on the day of bile acid concentration
measurement:
0 – no pruritus
1 – pruritus limited to palm surface of hands and
feet
2 – pruritus on hands, forearms and shins
3 – pruritus on arms, thighs and abdomen
4 – pruritus affecting the whole body
RESULTS
Biochemical markers analysis
Serum total bile acids (TBA) in the group of patients
with cholestasis of pregnancy (group I) ranged from
11.07 µmol/L to 87.68 µmol/L, average concentration
was 22.82±14.78 µmol/L. In group II TBA concentration
was respectively lower and ranged from 0 µmol/L to
9.31 µmol/L. The differences between the groups were
statistically significant (tab. I).
Erythropoietin (EPO) concentration in the group of
patients with cholestasis of pregnancy ranged from 1.6
to 41.9 mU/ml, average concentration was 17.35±8.86
mU/ml. EPO concentration measurements in the control
group were similar. The differences between the groups
were not statistically significant (tab. II).
In both of the analysed groups selected liver function
parameters in blood serum were determined. The average
activity of aspartate aminotransferase AST in group I was
178.82±136.54 U/L. In group II the average activity of
AST was evidently lower. The differences were statistically
significant (tab. III).
The average activity of alanine aminotransferase ALT
in group I was 314.27±210.71 U/L. In group II the activity
ranged from 7 to 113 U/L. In one patient from the control
group AST and ALT levels exceeded the upper limits of
normal with TBA at 6.22 µmol/L and the remaining liver
parameters within normal limits. No liver diseases were
found in medical history. The differences between the
groups were statistically significant (tab. III).
Total bilirubin concentration in the blood serum of
patients from group I ranged from 4.1 to 26.5 µmol/ L
with the average level within normal limits. No cases of
jaundice were reported in patients from this group. In group
II bilirubin concentration was within normal limits, its
average level was 6.28±2.26 µmol/L. The differences between
the groups were statistically significant (tab. III).
Test results for coagulation parameters were similar
in both groups with average levels within the lower limits
of normal. Average APPT in group I was 26.3±3.06 s.
In group II average APTT was 27.75±5.56 s (tab. III).
Likewise, PT and INR levels were similar in both groups
and within normal limits (Tab. III). D-dimer concentration
in both groups was increased, but higher values were
reported in pregnant patients from group I. In group
II the levels ranged from 254.5 to 1837.21 µg/L. The
differences between the groups were not statistically
significant (Tab. III). Fibrinogen levels in both groups
exceeded the upper limits of normal and the differeces
between them were statistically different. In group I the
average concentration was 593.75±123.92 mg/dl. In group
Table I. Total bile acids concentra!on (µmol/L) in the studied groups.
Tabela I. Całkowite stężenie kwasów żółciowych (µmol/L) w badanych grupach.
SD
Studied group
Mean
Min.
Odchylenie
Minimum
Grupa badana (n)
Średnia
standardowe
Group I
Grupa I
Group II
Grupa II
237
Max.
Maksimum
(33)
22.82
14.78
11.07
87.68
(40)
2.43
2.04
0
9.31
p
<0.05
Table II. Erythropoie!n concentra!on (µmol/L) in the studied groups.
Tabela II. Stężenie erytropoetyny (µmol/L) w badanych grupach.
Mean
Średnia
SD
Odchylenie
standardowe
Min.
Minimum
Max.
Maksimum
(33)
17.35
8.86
1.6
41.9
(40)
18.12
9.48
0.1
50.6
Studied group
Grupa badana (n)
Group I (B)
Grupa I
Group II (K)
Grupa II
p
0.68
Table III. Selected parameters of liver func!on in the studied groups.
Tabela III. Wybrane parametry funkcji wątroby w badanych grupach.
Group I
Grupa I
Group II
Grupa II
(n)
Mean
Śr.
Min.
Max.
SD
AST
(34)
175.09
53
526
ALT
(34)
306.59
53
Bilir. total
Bilir. całk.
(34)
11.32
APTT
(34)
PT
p
(n)
Mean
Śr.
Min.
Max.
SD
136.2
(40)
19.5
8
52
8.31
<0.05
823
212.27
(40)
18.5
7
113
17.7
<0.05
4.1
26.5
6.23
(40)
6.33
2.7
12.9
2.28
<0.05
26.28
21.2
34.3
3.04
(40)
27.85
22.3
58.7
5.76
0.18
(34)
10.59
8.9
12.8
0.88
(40)
10.47
9.6
12
0.56
0.39
INR
(34)
0.96
0.81
1.16
0.08
(40)
0.95
0.84
1.1
0.06
0.50
Fibrinogen
Fibrynogen
(34)
591.64
361.7
948
122.65
(40)
478.68
318
722
D-dimers
D-dimery
(32)
803.42
189.96
3066
758.7
(38)
608.52
II the average concentration was lower, and the levels
ranged from 318 to 722 mg/dl (tab. III).
The analysis of selected renal function parameters
indicated that urea concentration in both of the analysed
groups was within normal limits, and the results were not
different between the groups in a statistically significant
manner (tab. IV). Higher creatinine levels were found in
the blood serum of patients with cholestasis of pregnancy,
but in both groups the results were within normal limits.
The differences between the groups were not statistically
significant (tab. IV).
Selected blood count parameters in both groups were
on similar levels and within normal limits for pregnant
103.24 <0.05
254.05 1837.21 379.9
0.37
women. Average results were not different in a statistically
significant manner (tab. V).
Clinical studies
In both group I and group II all CTG records on the
day of blood collection for biochemical analyses were
normal.
In an ultrasound test in group I, fetal hypothropy was
recognized in 3 fetuses (7.32%). Additionally, one case
(2.44%) of oligohydramniosis and one case (2.44%) of
centralization of circulation was identified, both in the
same pregnant patient. Noteworthy, TBA concentration
in these cases was lower than average levels for the
238
Table IV. Selected parameters of renal func"on in the studied groups.
Tabela IV. Wybrane parametry funkcji nerek w badanych grupach.
Group I
Grupa I
Urea
Mocznik
Crea"nine
Kreatynina
Group II
Grupa II
p
(n)
Mean
Śr.
Min.
Max.
SD
(n)
Mean
Śr.
Min.
Max.
SD
(34)
2.54
1.19
6.03
0.97
(39)
2.71
1.27
6
0.98
0.22
(34)
60.5
35
77
9.09
(40)
47.6
32
69
8.14
0.16
Table V. Selected hematological parameters in the studied groups.
Tabela V. Wybrane parametry morfologii krwi w badanych grupach.
Group I
Grupa I
Group II
Grupa II
Min.
Max.
SD
(n)
3.5
4.44
0.25
(40)
Mean
Śr.
3.96
p
RBC
(34)
Mean
Śr.
3.95
HGB
HTC
(34)
(34)
11.91
35.76
11
32
13.7
43.8
0.73
2.45
(40)
(40)
12.1
35.77
11
31.5
14.8
42.6
0.9
2.55
0.37
0.60
PLT
(34)
205.53
112
319
52.43
(40)
199.5
103
348
54.26
0.50
(n)
whole group (22.82 µmol/L): 13.04 µmol/L in the case
of oligohydramniosis and 17.27 µmol/L in the case of
fetal hypotrophy and centralization of circulation.
In group I 36.4% (12) of patients gave birth to their
children naturally. 20 women ended up having Caesarean
section, while 6 patients (18.2%) had elective Caesarean
section. In 14 patients (42.4%) emergency C – section
procedure was performed due to the following indications:
no labour progress (n=5), threatening intrauterine fetal
asphyxia (n=4), preterm delivery in multiple pregnancy
(n=4), abnormal fetal presentation (n=1). Labor with the
use of vacuum extractor VE took place in one case (3%). It is
noteworthy that a total of 14 out of 33 pregnancies (42.4%)
were qualified for labour induction due to the presence or
intensified symptoms of cholestasis of pregnancy.
In group II 45% (18) of patients gave birth to their
children naturally. Caesarean section was performed in
20 patients, in 7 cases (17.5%) C – sections were elective.
13 patients (32.5%) had emergency C – section due to
the following indications: threatening intrauterine fetal
asphyxia (n=7), no labour progress (n=3), abnormal
fetal presentation (n=2), preterm delivery in multiple
pregnancy (n=1). Vacuum extractor VE was used twice
(5%) to complete the delivery.
In group I the average gestational age of newborns at
labour was 35.97±1.86 weeks, minimum gestational age
was 30 weeks, and the maximum 39 weeks. In the control
group the average gestational age at labour was higher
and amounted to 38.1±1.46 weeks. The gestational age
ranged from 36 weeks to 41 weeks (tab. VI).
What is worth noticing is a statistically significant
difference in the incidence of preterm labour in the
analysed groups (p=0.0045). 45.5% (15) of patients with
Min.
Max.
SD
3.38
4.64
0.3
0.95
cholestasis of pregnancy delivered before 37 weeks of
gestation. In group II 15% (6) of patients delivered
preterm, all of them at 36 weeks of gestation (Fig. 1).
In group I 12 pregnant patients developed spontaneous
contractions. In 2 cases pregnancies were ended at 36
weeks of gestation due to intensified cholestasis. In one
case, a Caesarean section was performed at 30 weeks of
gestation due to cholestasis – related fetal hypotrophy
and centralization of circulation. In patients with ICP,
who delivered preterm, the average gestational age was
34.47±1.64 weeks, with the minimum and maximum values
at 30 weeks and 36 weeks respectively. Average bile acid
concentration was 20.33±9.07 µmol/L, and PBA ranged
between 11.07 and 42.08 µmol/L. In group I women who
delivered after complete 37 weeks of gestation, average
TBA concentration was 24.9±18.25 µmol/L with extreme
values at 11.21 µmol/L and 87.68 µmol/L respectively.
Neonatal outcome at birth as well as the incidence
of intrauterine hypoxia episodes were analysed based
on intrapartum CTG records and on the presence of
meconium in amniotic fluid.
In group I intrapartum CTG records were normal in
90.2% (37) of fetuses. Abnormal CTG records were found
in 9.8% of fetuses (4). In two cases fetal bradycardia was
identified, however no meconium was found in amniotic
fluid. Neonatal outcomes were good. The presence of
persistent variable decelerations in CTG records in
one of the fetuses was associated with green tint to the
amniotic fuid, the newborn’s condition was good. In
one case oscillation in intrapartum CTG records was
narrow due to the longer duration of delivery. Neonatal
outcome of the delivery was good. Amniotic fluid was
tinted with meconium.
In group II the rate of normal intrapartum CTG
records was 82.6% (n=38). Abnormal CTG records
were observed in 8 cases (17.4%). Bradycardia occured
in 3 cases. Amniotic fluid was clear at all births and the
neonatal outcomes were good. Fetal arythmia in the
form of recurring variable decelerations was identified
in 4 CTG records. Meconium was found in amniotic
fluid twice. Three newborns were in a good condition, in
one newborn 1-minute Apgar score was 5, followed by
8 in 5-minute Apgar score. Recurring late decelerations
took place in CTG monitoring in one case, in one fetus
at twin birth. The condition of both newborns was good
and the amniotic fluid was clear.
In group I meconium was found at birth in amniotic
fuid, on fetal membranes or on the placenta in 14.6% (6)
of cases. In 2 cases the above – mentioned abnormalities
in CTG records were observed as well. Average TBA
concentration in these pregnant women was higher than
in the whole group and amounted to 36.21±26.97 µmol/L
with minimum and maximum values at 13.81 µmol/L
and 87.97 µmol/L respectively.
In group II amniotic fluid was found to be tinted with
meconium in 8.7% (4) of cases. In two of these cases fetal
arythmia was also observed in CTG records.
The results of Fisher’s exact test have not indicated
statistical significance (p>0.05) between the analysed
239
groups with reference to the presence of meconium in
amniotic fluid (p=0.29) and to abnormalities in intrapartum
CTG records (p=0.24)
Neonatal outcome was evaluated based on the body
weight, 1-minute and 5-minute Apgar score, as well as
selected blood gas parameters in the umbilical artery.
In group I the lowest birth weight was 910 g, and the
highest was 4010 g, the average weight was 2755.85 g.
Birth weight of 36.6% (15) of newborns was below 2500 g.
Low birth weight babies (1500 – 2500 g) accounted for
34.1% (n=14). There were no newborns with very low
birth weight (LBW) of 1000 – 1499 g. Extremely low
birth weight (750 – 999 g) was observed in the case of
one newborn baby (2.4%) (fig. 2).
In group II birth weight was higher than in group
I and ranged between 2060 g and 4120 g. Average birth
weight was 3134.57 g. Only 10.9% of newborns (n=5)
had low birth weight, <2500 g. No cases of very low
or extremely low birth weight were observed (fig. 2).
The results of Fisher’s exact test have indicated that the
differences in occurence of LBW between the groups
were statistically significant (p=0.005).
Neonatal outcomes in both groups were evaluated
based on Apgar score and are presented in table VII.
No cases of significant metabolic acidosis (pH<7.05,
BE>-12 mmol/L) were found in the analysis of blood
Table VI. Gesta"onal age (weeks) at delivery.
Tabela VI. Wiek ciążowy noworodków (tyg.) w czasie porodu.
Mean
Średnia
SD
Odchylenie
standardowe
Min.
Minimum
Max.
Maksimum
(41)
35.97
1.86
30
39
(46)
38.1
1.46
36
41
Studied group
Grupa badana (n)
Group I
Grupa I
Group II
Grupa II
Preterm delivery in the study groups, p<0,05
Porody przedwczesne w badanych grupach, p<0,05
Birth weight of newborns
Masa urodzeniowa noworodków
<37 tyg. ciąży (<37 week)
>37 tyg. ciąży (<37 week)
Ryc. 1. Preterm delivery in the studied groups.
Fig. 1. Porody przedwczesne w badanych grupach.
Ryc. 2. Birth weight of newborns.
Fig. 2. Masa urodzeniowa noworodków
p
<0.05
240
gas parameters in the umbilical artery in both groups of
newborns. Statistically significant differences were observed
between the groups for mean values of cord blood pH
(7.34±0.05 in group I vs 7.31±0.06 in group II, p=0.044) and
the values of partial pressure of oxygen (23.64±8.62 mmHg
in group I vs 18.85±7.16 mmHg, p=0.034). No statistically
significant differences were found in partial pressure of
carbon dioxide and buffer base concentrations.
The analysis of pruritus intensity in women with
the cholestasis of pregnancy was presented in table 8.
Kruskal-Wallis ANOVA test by ranks was used in order
to evaluate the association between pruritus intensity and
bile acid concentration. Based on its result (p=0.3266)
one can recognize that TBA concentration does not affect
the level of pruritus sensation. Median test (p=0.3187)
confirms this result. The results described were presented
in table VIII.
DISCUSSION
Elevated bile acid concentration defines the cholestasis
of pregnancy (7, 21). Diagnosing cholestasis of pregnancy
with TBA at 11 μmol/l or higher is advocated by i.a. Lammert
(13), Pusl (30) and Saleh (27) in their publications. Glantz
found TBA concentration ≥10 μmol/l as indicative of ICP
(21). Dann identified ICP when bile acid concentration
exceeded 14 μmol/l (34).
In the authors’ own research ICP was diagnosed if
TBA was 11 μmol/l or higher, and was accompanied
by the increased activity of liver aminotransferases and
pruritus. Average TBA concentration in group I was nearly
10 – fold higher than in the control group (p<0.05).
Indicators of hepatocyte damage are elevated ALT and
AST. Some authors, including Geenes and Wiliamson,
believe that ALT is a more sensitive and a better cholestasis
marker than AST (1, 13). Similar findings were reported
by Brzozowska (35).
In this analysis in group I the average activity of AST
was over 9 – fold higher than in group II, while ALT value
was nearly 17 – fold higher vs its activity in group II.
Alpha Glutathione S-Transferase (GSTA) is an
enzyme whose activity intensifies quickly in the case
of hepatocyte damage. Dann has considered GSTA
a more sensitive liver function parameter than the
enzymes routinely determined hitherto. In his study
GSTA level was elevated in 94% of patients with ICP,
while increased activity of ALT, AST or high TBA
concentration identified 63%-80% of cases of cholestasis
in pregnant women (34).
In the course of ICP elevated bilirubin levels occur
in approximately 20% of patients. The direct bilirubin
fraction is increased (1, 11, 13, 15). Jaundice is present in
10-15% of pregnant patients with ICP, and according to
Dann et al. in as few as 2% (1, 34). In the paper published
by Polish scientists the bilirubin levels were normal in
all cases of cholestasis of pregnancy (35).
In this analysis average total bilirubin levels in both
groups of pregnant women were within normal limits,
Table VII. Neonatal outcomes.
Tabela VII. Stan urodzeniowy noworodków.
Apgar score
Punktacja
Apgar
Neonatal
outcomes
Stan
noworodków
≥8 pkt.
4-7 pkt.
0-3 pkt.
Group I (n=41)
I grupa
Group II (n=46)
II grupa
p
1st minute
1-sza
minuta
5th minute
5-ta
minuta
1st minute
1-sza
minuta
5th minute
5-ta
minuta
Good
Dobry
32
(78.1%)
35
(85.4%)
44
(95.7%)
46
(100%)
Average
Średni
Bad
Zły
9
(21.9%)
6
(14.6%)
2
(4.3%)
0
0
0
0
0
1st minute
1-sza
minuta
5th minute
5-ta
minuta
0,015
0,009
As cb
Table VIII. Intensity of pruritus and TBA concentra"on in the group with ICP.
Tabela VIII. Natężenie świądu skóry a stężenie TBA w grupie pacjentek z ICP.
Intensity of Pruritus
Natężenie świądu
TBA concentra!on
Stężenie TBA (µmol/L)
p
SD
Min.
Max.
15.15
Mean
Śr.
32.98
53.85
11.21
87.68
(8)
24.2
21.3
10.23
11.07
36.59
2
(5)
15.15
20.19
0.54
13.04
33.78
3
(3)
9.1
12.65
1.2
11.3
13.66
4
(12)
36.4
23.24
0.47
13
39
(n)
%
0
(5)
1
0,33
although they were higher in a statistically significant
manner in group I (p<0,05). Jaundice was not found in
these patients.
As far as ICP – related changes in the coagulation
system are concerned, most scientists, including Pisarek-Miedzińska, have not found abnormal PT values, INR,
APTT, fibrinogen level and platelet count in patients
with ICP in comparison to healthy pregnant women
(29). In a single study performed in the 1980s of the
20th century in the Chinese population, a prolonged
prothrombin time was observed in 20% of women
with ICP (1).
The results of this study are found in a few publications
worldwide, in which statistically significant deviations
in coagulation system were identified in the course of
ICP. On analysing coagulogram parameters the authors
found that fibrinogen levels exceeded the upper limits
of normal both in the study group and in the control
group, and the differences in the mean values were
statistically significant (p<0.05). In both groups of
women, in turn, APTT and prothrombin time as well
as INR were similar and their mean values were within
normal limits. D-dimer concentration was increased in
both groups with higher values presented by patients
with cholestasis of pregnancy, although the differences
were not statistically significant.
Smolarczyk et al. have identified renal dysfunction in
the course of cholestasis, manifested by reduced 24-hour
diuresis, elevated serum creatinine and uric acid level, lower
albumin levels, unaccompanied by albuminuria. However,
the authors have not found changes in concentrations of
sodium and potassium ions in urine and blood serum
(36).
In this study evaluated markers of renal function (urea,
creatinine) were within normal limits both in women
with ICP, as well as in gravidae from the control group.
The differences in mean values were not statistically
significant.
Pruritus is the most common complaint reported by
pregnant women with cholestasis. In Kenyon’s study pruritus
preceded biochemical symptoms of cholestasis (37). The
intensity of pruritus is not correlated with the activity of
liver enzymes and bile acid concentration. In a population
analysed by Lee et al. the maximum intensity of pruritus
was associated with elevated bile acid concentration in
only 60% of women (38). The lack of link between TBA
and pruritus was also described in 2008 by Glantz et al.
However, it was then found that pruritus can be associated
with the concentration of sulfated progesterone metabolites
in blood serum of pregnant women with ICP (39). Also
the Polish scientists, Grymowicz and Czajkowski, indicate
there is no association between the intensity of pruritus
and TBA concentration. Nevertheless, they have identified
a statistically significant, linear dependence of pruritus
on bilirubin levels and the activity of AST in the blood
of women included in the study (40).
Similar results were obtained in this analysis. TBA
concentration did not affect the intensity of pruritus in
a statistically significant manner.
The most common obstetric complication in pregnant
women with cholestasis is preterm labour (1, 22). According
241
to Glantz’s observations the risk of preterm delivery is higher
if TBA concentration exceeds 40 μmol/L. In her study
spontaneous labour before 37 weeks of gestation occured
in 2.7% of pregnant patients without ICP, in 2.2% of women
with moderately severe disease (TBA: 10-39 μmol/L) and
in 16.7% of patients with ICP and bile acid concentration
of at least 40 μmol/L (21). In Kondrackiene’s study the
rate of preterm deliveries was 13.3. The most important
predictive factor of preterm delivery was increased TBA
concentration before the onset of therapy and early occurence
of pruritus (41). In her population Roncaglia found that
the pregnancy ended before 37 weeks of gestation in 27.2%
of pregnant women with ICP in comparison to 9% in the
general population. The average gestational age at birth
was 37.4 weeks (42).
In the authors’ own study preterm delivery was 3 times
more common in pregnant women with ICP (p=0.0045).
In this group the average gestational age at birth was
35.97±1.86 weeks, while in the control group 38.1±1.46
weeks (p<0,05). On analysing the association between
preterm delivery and TBA concentration, it was found
that in patients with ICP who delivered prematurely, the
average TBA concentration was slightly lower than the
average level for the whole group and over 20% lower
than in the women with cholestasis of pregnancy with
delivery at full term. In this study the measurement of
bile acid concentration was conducted only once, and
several days up to as long as four weeks passed from
TBA measurement until labour.
It is noteworthy that a significant number of preterm
deliveries in the case of cholestasis of pregnancy is currently
iatrogenic in nature. It results from the adoption of active
management model that involves elective delivery at about
37 weeks of gestation in the case of ICP. Mays asserts
that active obstetric management aims to avoid or reduce
the risk of severe fetal complications (14). In a study by
Glantz’s team the labour induction after 37 weeks of
gestation took place in 32% of women with intensified
cholestasis and in 24% of pregnant patients with moderately
severe disease (21). The results presented by Roncaglia
indicate that labour induction was performed in 71% of
pregnancies complicated by cholestasis and over 20% of
them ended up in Ceasarean section, most commonly
due to ineffective induction (1/3 of cases) or threatening
intrauterine fetal asphyxia (1/3 of cases) (42).
The presented results of the authors’ own analysis are
in line with the quoted publications. 42.4% of pregnant
patients from the study group were qualified for labour
induction or elective Caesarean section after 37 weeks of
gestation due to the presence or more intense symptoms
of cholestasis of pregnancy. 45.4% of women with ICP
delivered via emergency C – section or with the use
of a vacuum extractor. The analysis of indications for
Caesarean delivery showed that in patients with ICP
the most frequent reason was no labour progress and
threatening intrauterine fetal asphyxia.
In women with ICP the rate of intrauterine fetal deaths
is currently appx. 3.5% (1, 22). Evidence in favour of the
increased risk of intrauterine fetal death after 37 weeks
of gestation is the reason for elective delivery in the case
of pregnancies complicated by ICP after this deadline (1,
242
15, 27). It is believed that elevated bile acid concentration
is associated with higher risk of fetal death, although the
patomechanism behind this link has not been well elucidated
yet (21). Sepulveda has observed vasoconstrictory effect
of cholalic acid and deoxycholic acid on venous vessels of
placental villi, which resulted in reduced placental blood
flow (26). The authors of this study point to the fact that
bile acid concentration in an in vitro model were higher
compared to concentrations found in fetal circulation
or in the blood serum of women with ICP (26). On the
other hand, under in vivo conditions there also occur
other vasoconstrictory substances that can enhance the
disadvantageous effect of bile acids (26). In animal studies
taurocholic acid was found to cripple contractility and to
have arythmogenic effect on cardiac muscle cells (11, 27).
Williamson has demonstrated that fetal cardiomyocytes
are more vulnerable to the arythmogenic effect of bile
acids than mature cardiac muscle cells (43). It was also
discovered that the arythmogenic effect of bile acids was
blocked by ursodeoxycholic acid (UDCA) (43). In Glantz’s
study the rate of intrauterine fetal deaths was 0.4% and
in 2/3 of cases TBA concentration was multi-fold (9 –
13x) higher than the upper limit of normal (21). In his
study Kondrackiene has not observed the incidence of
intrauterine fetal death in women with ICP (41). Similar
findings were presented by Roncaglia (42).
In the observations presented no incidents of intrauterine
fetal death in women with ICP or in the control group
were found either.
According to Shaw, amniotic fluid tinted with meconium
was found in 16% to 58% pregnancies complicated by
cholestasis (18). The fact that the amniotic fluid is more
commonly tinted with meconium in patients with ICP is
associated with higher TBA concentration (1). Campos
has demonstrated that the admnistration of cholalic acid
to pregnant sheep accelerates meconium passage and
contributes to its more frequent presence in amniotic fluid
(44). The accumulation of cholalic acid in meconium can
cause fetal well-being to deteriorate (27). Bile acids transfer
across the placenta in both directions. In a physiological
pregnancy bile acid concentration in maternal blood
is lower than in the fetus, which is supposed to enable
their transplacental elimination to the fetus. Sales asserts
that in the course of ICP mother – to – fetus bile acids
transport intensifies with subsequently higher bile acid
concentration in amniotic fluid, fetal blood serum and
in meconium (13, 27). In an experimental model of
the cholestasis of pregnancy in female rats, a riversible
impairment of fetal mechanisms regulating hepatocytes
and cholangiocytes functions was identified (6, 11). Jóźwik
points to the fact that the question if toxic accumulation of
bile acids in fetus is of maternal origin or if it also results
from fetal disorders, remains unsolved (19). According
to the results presented by Glantz et al. meconium was
found in amniotic fluid in 44% of pregnancies complicated
by severe cholestasis (TBA>40 μmol/L) and in 21% of
pregnancies without this pathology. They believe that the
risk of meconium presence does not increase if bile acid
concentration is lower than 40 μmol/L (21). Roncaglia
has identified meconium passage to amniotic fluid in
15.1% of pregnancies with cholestasis (42).
In the authors’ own study meconium was found to be
present in amniotic fluid at birth in 14.6% of patients with
ICP, almost 1.7 more frequently than in the control group,
however this result was not statistically significant.
The ICP abnormal cardiotocography (CTG) pattern
is observed, both during pregnancy, as well as during
perinatal monitoring of fetal well-being. Mullally and
Pusl agree on more common incidence of tachycardia,
bradycardia episodes, as well as persistent narrow oscillation
of fetal heart rate (FHR) (28, 30). In a study by Italian
scientists fetal distress syndromes necessitating a C – section
delivery occurred in 5.3% of pregnancies complicated
by cholestasis. Glantz reports that only 3.5% (52/1479)
CTG records at rest, performed within the surveillance of
pregnancy complicated by ICP, presented abnormalities
which in most cases receded spontaneously and did not
require an obstetric intervention (21).
In the authors’ own study no abnormal CTG records
at rest (conducted on the same day as the scheduled
biochamical analyses) were observed in pregnant women
with cholestasis. During intrapartum fetal surveillance
in women with ICP abnormalities in CTG records were
observed in nearly 10% of the study group. For this
reason deliveries were ended via emergency C – section
or with the use of a vacuum extractor.
In Scandinavian studies episodes of fetal asphyxia at
birth were identified in 13.5% of cases of severe cholestasis
and in only 6.3% of moderate cholestasis cases, as well as
in 5.4% of women without ICP. Asphyxia was diagnosed
if blood pH in umbilical artery was <7.05, and 5-minute
Apgar score was <7 (21). In Roncaglii’s study only less
than 1% of newborns received the 5-minute Apgar score
below 7, and acute acidosis (pH=7.06) occured in one
infant (0.48%) who additionally suffered from congenital
lung malformation (42).
In their own studies the authors have demonstrated that
there were fewer positive neonatal outcomes in mothers
with cholestasis compared to the control group. There
were 4.5 times more children with 1 – minute Apgar
score < 8 born by mothers with cholestasis (p=0.0149).
In the control group no infants obtained the 5-minute
Apgar score of 7 or less, while in the study group they
accounted for 14.6% of newborn babies (p=0.0089).
Ultrasound combined with Doppler blood flow
spectrum evaluation in fetal circulation and uteroplacental
circulation is one of the basic methods of fetal wellbeing evaluation and monitoring (19, 45). It allows
for early diagnostics of changes caused by intrauterine
hypoxia, identification of high risk groups as well as the
implementation of intense surveillance. However, Jóźwik
points out that published results of studies on changes in
the vascular flow in pregnant women with cholestasis are
contradictory (19). At the beginning of the 1990s there
were reports of no changes in umbilical vessel flows
in pregnancies complicated by intrahepatic cholestasis
(Zimmermann et al.) (46). According to Rauramo et
Forss even light physical activity in pregnancies with
ICP caused vascular resistance in the umbilical artery to
an even greater extent than in pregnancies complicated
by hypertension or diabetes (47). Similar findings were
presented by Łoziński (20). In 2010 Zhang and Dong
demonstrated abnormal values of the pulsatility index
and the systolic/diastolic ratio in umbilical artery, which
was associated with lower birth weight, higher rates
of preterm deliveries, excessively low weight at birth
against gestational age (small for gestational age, SGA)
and more frequent hospitalization in neonatal intensive
care units (48).
In the results presented the Doppler vascular flow
spectrum evaluation was abnormal in only 2.44% (1
per 41) of fetuses from the group of mothers with ICP.
The pregnant patient was a 30-year-old primigravida in
a singular pregnancy at 30 weeks of gestation. Apart from
the centralization of circulation, fetal hypotrophy and
oligohydramniosis were identified. On that day the patient
presented normal CTG records. Bile acid concentrations,
erythropoietin and the activity of aminotransferases AST
and ALT were below mean values in the whole group.
The woman was qualified for C – section delivery due
to ICP, fetal hypotrophy and abnormal vascular flow.
A female newborn was delivered from clear amniotic
fluid, with weight at birth at 910 g as well as 7 and 8
Apgar score and normal blood gas parameters in the
umbilical artery.
Pathak, Pusl and Geenes point out that the available
literature does not provide evidence of increased risk of
intrauterine growth restriction (IUGR) in pregnancies
complicated by cholestasis (1, 2, 30). Fagan and Lammert
deliberate whether the scarce incidence of IUGR or of
instances of fetal death in pregnant women with cholestasis
can confirm the theory that in the course of ICP the
episodes of fetal hypoxia are rather acute, and not chronic
in nature (13, 49). In the ICP population analysed by
Roncaglia, oligohydramniosis was reported in just over
3%, and hypotrophy in nearly 7% of fetuses (42).
In this study the results obtained were similar to the
findings of Italian scientists. Hypotrophy was identified
in 7.32% of fetuses in pregnant patients with ICP.
Oligohydramniosis was observed in 2.44% of pregnancies
complicated by cholestasis.
Erythropoietin is a hormone, whose synthesis is
stimulated by tissue hypoxia (50, 51, 52). The problem
regarding changes in erythropoietin concentrations in
pregnancy complicated by impaired placental blood
circulation was described in detail in another publication
of the author (33).
Impaired placental circulation is also proposed as
a reason for fetal complications associated with intrahepatic
cholestasis of pregnancy. The factor considered their driver
is elevated bile acid concentration. Glantz has proved that
the risk of fetal hypoxia increases by 1% - 2% per each
additional μmol/L of bile acids (21). In an in vitro analysis
Sepύlveda found reduced placental circulation, which
resulted from the vasoconstrictory effect of cholalic acid
and deoxycholic acid on venous vessels of placental villi
in pregnancies complicated by cholestasis (26). Studies
conducted in rodents and in humans have proved that
in the course of ICP reverse bile acid transplacental
gradient is observed (53). The elevated TBA level can affect
the structure of the placenta and result in deteriorated
competence of the placenta as well as crippled oxygen and
nutrient transport. In a publication from 2011 Geenes
243
indicated that the placenta of pregnant rodents with
cholestasis displays abnormalities in their structure (less
intervillous space, nuclear clusters in syncytiotrophoblast
called syncytial knots) (53). One of the reasons for the
formation of syncytial knots may be hypoxia (53). The
author sees the confirmation that it is placental hypoxia
that drives the formation of syncytial knots in lower
cord blood pH in healthy newborns of mothers with
ICP (21, 53). In an animal model of cholestasis Perez
described intensified apoptosis processes and oxidative
stress markers in placenta, identified increased protein
carbonylation and lipid peroxidation (54).
Placental changes in pregnancies complicated
by ICP have not been recognized well. Łoziński has
indicated that their dimensions and weight were lower
compared to afterbirths from pregnancies complicated
by other pathologies (20). There were reports of changes
corresponding to the premature aging of the placenta:
hemosiderin deposition, abnormal structure of villous
vessels. Studies conducted over 35-38 weeks of gestation
have shown impaired placental secrection that was
manifested by a 2 times lower blood serum estrogen
concentration in pregnant women with ICP, compared
to healthy gravidas (19).
Studies evaluating erythropoietin production in the
course of the cholestasis of pregnancy have not been
conducted hitherto. A hypothesis in the authors’ own study
assumed a potential analogy between the processes ocurring
in preeclempsia and in the cholestasis of pregnancy. In the
course of ICP elevated bile acid concentrations can cause
reduced blood flow through the fetal – placental unit,
which can result in placental hypoxia. In consequence of
local tissue hypoxia intensified placental erythropoietin
secretion can occur.
In this study selected parameters of renal function
evaluation in pregnant patients with cholestasis did not
differ from the control group in a statistically significant
manner. The analysed hematological parameters: red blood
cell count, hemoglobin concentration and hematocrit
values were normal in both groups, and the mean values
did not differ between the groups in a statistically significant
manner. Pregnant women with anemia were exluded from
the analysis in order to receive objective EPO measurements.
The erythropoietin concentrations obtained were similar
in both groups, with slightly higher values in the control
group (17.35±8.86 vs 18.12±9.48 mU/ml). The mean values
did not differ in a statistically significant manner. Moreover,
Spearman’s rank correlation coefficient indicated a negative
association between erythropoietin concentration and
hematocrit values and urea concentration.
The reason for no difference in EPO concentration
values between the groups can consist in a very low
number of women with cholestasis of pregnancy who
displayed traits of impaired placental circulation. Abnormal
vascular flow in ultrasonography was presented in only
one fetus (2.44%).
We think that the role and the mechanism of potential
increase of erythropoietin concentration in the course
of cholestasis of pregnancy or preeclepsia requires
further studies. The pathomechanism and the clinical
consequences of preeclempsia are much better recognized
244
than the reasons for complications related to intrahepatic
cholestasis of pregnancy. Consequently, future reasearch
can be concentrated i.e. around further evaluation of
the role and regulation of EPO secretion in selected
pathologies of pregnancy.
CONCLUSIONS
1. In the analysed group of pregnant women with intrahepatic cholestasis no association was found between
bile acids and erythropoietin concentrations.
2. Findings regarding more common incidence of preterm delivery and worse neonatal outcome in the ICP
group indicate that perinatal care should be improved
and further studies are needed.
REFERENCES
1. Geenes V., Wiliamson C.: Intrahepatic cholestasis of pregnancy.
World J. Gastroenterol. 2009, 15(17), 2049-2066.
2. Pathak B., Sheibani L., Lee R.H.: Cholestasis of pregnancy.
Obstet. Gynecol. Clin. N. Am. 2010, 37, 269-282.
3. Lucena J-F., Herrero I., Quiroga J. et al.: A multidrug resistance
3 gene mutation causing cholelithiasis, cholestasis of
pregnancy, and adulthood biliary cirrhosis. Gastroenterology
2003, 124, 1037-1042.
4. Gonzalez M.C., Reyes H., Arrese M. et al.: Intrahepatic
cholestasis in pregnancy in twin pregnancies. J. Hepatol.
1989, 9, 84-90.
5. Riosecco A.J., Ivancovic M.B., Manzur A. et al.: Intrahepatic
cholestasis of pregnancy: a retrospective case-control study
of perinatal outcome. Am. J. Obstet. Gynecol. 1994, 170,
890-895.
6. Arrese M., Macias R.I.R., Briz O. et al.: Molecular pathogenesis
of intrahepatic cholestasis of pregnancy. Expert. Rev. Mol.
Med. 2008, 10, 1-18.
7. Jóźwik M., Jóźwik M., Bartnicki J. i wsp.: Wewnątrzwątrobowa
cholestaza ciężarnych − niedoceniony problem medycyny
płodowej. Część I. Stan matki. Ginekol. Pol. 2007, 78, 312316.
8. Reyes H., Sjövall J.: Bile acids progesterone metabolites in
intrahepatic cholestasis of pregnancy. Ann. Med. 2000, 32,
94-106.
9. Reyes H.: Sex hormones and bile acids in intrahepatic
cholestasis of pregnancy. Hepatology 2008, 47, 376-379.
10. Vallejo M., Briz O., Serrano M.A. et al.: Potential role of
trans-inhibition of the bile salt export pump by progesterone
metabolites in the etiopathogenesis of intrahepatic cholestasis
of pregnancy. J. Hepatol. 2006, 44, 1150-1157.
11. Arrese M., Reyes H.: Intrahepatic cholestasis pf pregnancy:
a past and present riddle. Ann. Hepatol. 2006, 5(3), 202-205.
12. Zecca E., de Luca D., Baroni S. et al.: Bile acid-induced
lung injury in newborn infants: a bronchoalveolar lavage
fluid study. Pediatrics 2008, 121, 101-106.
13. Lammert F., Marschal H-U., Glantz A. et al.: Intrahepatic
cholestasis of pregnacy: molecular pathogenesis, diagnosis
and management. J. Hepatol. 2000, 33, 1012-1021.
14. Mays J.K.: The active management of intrahepatic cholestasis
of pregnancy. Curr. Opin. Obstet. Gynecol. 2010, 22, 100103.
15. Nichols A.A.: Cholestasis of pregnancy. A review of evidence.
J. Perinat. Neonat. Nurs. 2005, 19(3), 217-225.
16. Goulis D.G., Walker I.A., de Swiet M., et al.: Preeclampsia with
abnormal liver function tests is associated with cholestasis
in a subgroup of cases. Hypertens Pregnancy 2004, 23,
19-27.
17. Vanjak D., Mareau R., Roche-Sicot J. et al.: Intrehepatic
cholestasis of pregnancy and acute fatty liver of pregnancy.
An unusual but favorable association? Gastroenterol 1991,
100, 1123-1125.
18. Shaw D., Frohlich J., Wittmann B.A. et al.: A prospective
study of 18 patients with cholestasis of pregnancy. Am. J.
Obstet. Gynecol. 1982, 142, 621-625.
19. Jóźwik M., Jóźwik M., Bartnicki J. i wsp.: Wewnątrzwątrobowa
cholestaza ciężarnych-niedoceniony problem medycyny
płodowej. Część II. Stan płodu i postępowanie lekarskie.
Ginekol. Pol. 2007, 78, 405-410.
20. Łoziński T.: Wpływ wewnątrzwątrobowej cholestazy
ciężarnych na przebieg ciąży, poród i stan noworodka
u kobiet z Podkarpacia w latach 1998-2002. Rozprawa
doktorska. Warszawa: Akademia Medyczna, 2003.
21. Glantz A., Marschall H-U., Mattsson L-A.: Intrahepatic
cholestasis of pregnancy: Relationships between bile acid
levels and fetal complication rates. Hepatology 2004, 40,
467-474.
22. Cichoż-Lach H.: Patogeneza chorób wątroby związanych
z ciążą. Ginekol. Pol. 2010, 81, 613-617.
23. Lee R.H., Kwok K.M., Ingles S. et al.: pregnancy outcomes
during an era of aggressive management for intrahepatic
cholestasis of pregnancy. Am. J. Perinatol. 2008, 25, 341345.
24. Germain A.M., Kato S., Carvajal J.A. et al.: Bile acids increase
response and expression of human myometrial oxytocin
receptor. Am. J. Obstet. Gynecol. 2003, 189, 577-582.
25. Laatikainen T., Ikonen E.: Fetal prognosis in obstetric
hepatosis. Am. Chir. Gynaecol. Fenn. 1975, 64, 155-164.
26. Sepύlveda W.H., Gonzalez C., Cruz M.A., et al.: Vasoconstrictive
effect of bile acids on isolated human placental chorionic
veins. Eu. J. Obstet. Gynecol. Repr. Biol. 1991, 42, 211215.
27. Saleh M.M., Abdo K.R.: Intrahepatic cholestasis of pregnancy:
review of the literature and evaluation of current evidence.
J. Women’s Health 2007, 16(6), 833-841.
28. Mullally B.A., Hansen W.F.: Intrahepatic cholestasis of
pregnancy: Review of literature. Obstet. Gynecol. Survey
2001, 57(1), 47-52.
29. Pisarek-Miedzińska D., Hoffman A.: Czynniki układu
krzepnięcia w cholestazie ciężarnych. Hepatol. Pol. 1997,
4, 157-161.
30. Pusl T., Beuers U.: Intrahepatic cholestasis of pregnancy.
Orphanet. J. Rare Dis. 2007, 2, 26.
31. Marciniak B., Kimber-Trojnar Ż., Leszczyńska-Gorzelak B. i wsp.:
Leczenie cholestazy ciężarnych za pomocą wielonienasyconej
fosfatydylocholiny i kwasu ursodeoksycholowego. Ginekol.
Pol. 2011, 82, 26-31.
32. Hirvioja M.L., Tuimala R., Vuori J.: The treatment of
intrahepatic cholestasis of pregnancy by dexamethasone.
Br. J. Obstet. Gynaecol. 1992, 99, 109-111l.
33. Kowalska-Kańka A., Maciejewski T., Niemiec K.T.: The role
of secretion of erythropoietin in pregnancy. Dev. Period.
Med., 2013, XVII, 3, 270-275.
34. Dann A.T., Kenyon A.P., Seed P.T. et al.: Glitathione
S-transferase and liver function in intrahepatic cholestasis
of pregnancy and pruritus gravidarum. Hepatology 2004,
40, 1406-1414.
35. Brzozowska M., Kowalska-Koprek U., Karowicz-Bilińska A.:
Wpływ leczenia farmakologicznego na wybrane wykładniki
cholestazy ciężarnych. Ginekol. Pol. 2010, 81, 94-98.
36. Smolarczyk R., Wójcicka-Jagodzińska J., Romejko E. et al.: The
biochemical functions of the renal tubules and glomeruli
in the course of intrahepatic cholestasis in pregnancy. Eur.
J. Obstet. Gynecol. Reprod. Biol. 2000, 89, 35-39.
37. Kenyon A.P., Piercy C.N., Girling J. et al.: Pruritus may
precede abnormal liver function tests in pregnant women
with obstetric cholestasis: a longitudonal analysis. BJOG
2001, 108, 1190-1192.
38. Lee R.H., Goodwin T.M, Greenspoon J et al.: The prevelence
of intrahepatic cholestasis of pregnancy in a primrily Latina
Los Angeles population. J. Perinatol. 2008, 26, 527-532.
39. Glantz A., Reilly S-J., Bemthin L. et al.: Intrahepatic cholestasis
of pregnancy: amelioration of pruritus by UDCA is associated
with decreased progesterone disulphates in urine. Hepatology
2008, 47, 544-551.
40. Grymowicz M., Czajkowski K.: Świąd skóry u pacjentek
z wewnątrzwątrobową cholestazą ciężarnych leczonych
kwasem ursodeoksycholowym. Perinatologia, Neonatologia
i Ginekologia 2009, 2(2), 145-150.
41. Kondrackiene J., Beuers U., Zalinkevicius R. et al.: Predictors of
premature delivery with intrahepatic cholestasis of pregnancy.
World J. Gastroenterol. 2007, 13(46), 6226-6230.
42. Roncaglia A.J., Arreghini A., Locatelli A. et al.: Obstetric
cholestasis; outcome with active management. Eur. J. Obstet.
Gynecol. Reprod. Biol. 2002, 100, 167-170.
43. Williamson C., Miragoli M., Kadir S.S.A. et al.: Bile acid
signaling in fetal tissues: imlications for intrahepatic cholestasis
of pregnancy. Digestive Diseases 2011, 29, 58-61.
44. Campos G.A., Guerra F.A., Israel E.J.: Effects of cholic acid
infusion in fetal lambs. Acta Obstet. Gynecol. Scand. 1986,
65, 23-26.
45. Brązert J., Persona-Śliwińska A.: Badanie ultrasonograficzne
w trzecim trymestrze ciąży. W: Diagnostyka prenatalna
z elementami perinatologii. Red. Wielgoś M. 2009, 130136.
245
46. Zimmermann P., Koskinen J., Vaalamo P. et al.: Doppler
umbilical artery volecimetry in pregnancies complicated by
intrahepatic cholestasis. J. Perinat. Med. 1991, 19, 351-355.
47. Rauramo I., Forss M.: Effect of exercise on placental blood
flow in pregnancies complicated by hypertension, diabetes
or intrahepatic cholestasis. Acta Obstet. Gynecol. Scand.
1988, 67, 15-20.
48. Zheng K., Dong M.: Relationship between umbilical artery
Doppler waveform analysis and perinatal prognosis in
women with intrahepatic cholestasis of pregnancy. Int. J.
Gynaecol. Obstet. 2010, 111(2), 187-188.
49. Fagan E.A.: Intrahepatic cholestasis of pregnancy. Clinics
in liver disease 1999, 3, 603-632.
50. Eckardt K-U., Kurtz A.: Regulation of erythropoietin
production. Eur. J. Clin. Invest. 2005, 35, 13-19.
51. Nangaku M., Eckardt K-U.: Hypoxia and the HIF system
in kidney disease. J. Mol. Med. 2007, 85, 1325-1330.
52. Stockmann C., Fandrey J.: Hypoxia-induced erythropoietin
production: a paradigm for oxygen-regulated gene expression.
Clin. Exp. Pharmacol. Physiol. 2006, 33, 968-979.
53. Geenes V.L., Lim Y-H., Bowman N. et al.: A placental phenotype
for intrahepatic cholestasis of pregnancy. Placenta 2011;
doi:10.1016/j.placenta.2011.09.006
54. Perez M.J., Macias R.I.R., Marin J.J.G.: Maternal cholestasis
induses placental oxidative stress and apoptosis. Protective
effect of ursodeoxycholic acid. Placenta 2006, 27, 34-41.
Author’s contributions/Wkład Autorów
According to the order of the Authorship/Według kolejności
Conflicts of interest/Konflikt interesu
The Authors declare no conflict of interest.
Autorzy pracy nie zgłaszają konfliktu interesów.
Received/Nadesłano: 26.02.2013 r.
Accepted/Zaakceptowano: 11.06.2013 r.
Published online/Dostępne online
Address for correspondence:
Aneta Kowalska-Kańka
Klinika Położnictwa i Ginekologii
Instytut Matki i Dziecka
ul. Kasprzaka 17a, 01-211 Warszawa
tel. (22) 32-77-044,
e-mail: [email protected]

the concentrations of bile acids and erythropoietin in pregnant

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