Fetal hepatic artery blood flow velocimetry in normal and high-risk pregnancies

Aim To record blood flow velocity in the fetal hepatic artery in the course of normal pregnancies and to ascertain whether recordings in high-risk pre gnancies might indicate vascular sparing of the liver and predict perinatal outcome. Materials and methods Fetal hepatic artery blood flow velocity was recorded in a cross-sectional study in 75 normal pregnancies between 27 and 41 week s of gestation. Reference curves were constructed for the pulsatility index IPI) and resistance index (RI). The hepatic artery was also located in 50 singleton pregnancies complicated by pregnancy-induced hypertension and sus pected intrauterine growth restriction between 28 and 41 weeks of gestation . Middle cerebral artery, umbilical artery and vein, and uterine artery vel ocities were also recorded. Results Hepatic artery PI and RI values decreased gradually until 33 weeks' gestation, with a further increase in resistance to blood flow with increa sing gestational age. In high-risk pregnancies, the fetal hepatic artery P1 decreased (<2.5th centile) in 28 cases and increased (> 97.5th centile) in five cases. The hepatic artery RI decreased (< 2.5th centile) in 17 cases and increased (> 97.5th centile) in three cases. The group with values with in the normal range had a worse perinatal outcome than the group with decre ased vascular resistance. The hepatic artery RI was significantly higher in cases of adverse perinatal outcome. Conclusions The results suggest that vascular sparing of the fetal liver ca n be seen at an early stage of fetal compromise. This sparing effect might disappear in more severely affected fetuses.