Doppler umbilical artery velocimetry in pregnancies complicated by intrahepatic cholestasis

Abstract

Doppler umbilical velocimetry is a useful clinical tool for antepartum fetal surveillance of pregnancies at risk of fetal compromise. Intrahepatic cholestasis of pregnancy is associated with an increased incidence of fetal death, which might due to the toxic effect of elevated maternal serum concentrations of bile acids. To study a possible effect of the concentration of bile acids on the umbilical circulation we performed pulse-wave Doppler velocimetry of the umbilical artery in 15 patients with intrahepatic cholestasis between 34 and 38 weeks of gestation. The findings were compared to the Doppler flow velocities of the umbilical artery of 129 normal pregnancies. Peak-systolic (A) and end-diastolic (B) velocities of two to three cardiac cycles were measured by electronic calipers and the Pourcelot (PR)-index (PR = (A - B)(A)) was calculated. Two of 29 Doppler measurements in patients with intrahepatic cholestasis were above two standard deviations (2 SD) of the values in normal pregnancies. No significant correlation was found between Doppler flow velocities and serum levels of bile acids (r = 0.20) or the levels of alanine aminotransferase (ALAT) (r = -0.05). The mean level of bile acids was 24 mumol/l with a maximum of 98 mumol/l. The mean level of ALAT was 165 IU/l with a maximum of 576 IU/l. Since even high levels of bile acids do not influence umbilical circulation, Doppler investigations of the umbilical artery seem to be of little value in studying the disease-specific risk of fetal compromise in pregnancies complicated by intrahepatic cholestasis.