Fetal haemodynamics before and after treatment of maternal hypertension in pregnancy

The haemodynamics of fetuses of 15 pregnant women who developed hypertension during the last trimester of pregnancy were investigated before and after antihypertensive treatment using the ultrasound-Doppler method for non-invasive measurements of blood flow, and the results were compared to those from investigations of fetuses from normal pregnancies. In the untreated condition, significant reduction of blood flow was demonstrated in the fetal descending aorta (p less than 0.01) and in the umbilical vein (p less than 0.02). The resistance to flow, expressed as the Pulsatility Index, was significantly elevated (p less than 0.001). A significant correlation was shown between Pulsatility Index and maternal diastolic blood pressure (p less than 0.001) and a significant negative correlation between blood velocity in fetal aorta and maternal diastolic blood pressure (p less than 0.01). Treatment resulted in significant reduction of resistance to flow, which remained normal for the rest of the pregnancy. It is concluded that fetal haemodynamics are affected by maternal hypertension during pregnancy. The results suggest that the fetus also suffers from hypertension. Therapy with oral alpha-methyldopa and labetalol combined with volume expansion with human albumine normalised fetal circulation and kept it normal for the remainder of the pregnancy.