Fetal blood flow in diabetic pregnancy.

Forty pregnant diabetic women were examined with combined Doppler and real-time ultrasound. The volume blood flow in the fetal aorta and umbilical vein was higher and the pulsatility index (PI) in the aorta lower in the early third trimester, as compared with a reference group. Near term, the umbilical artery PI was higher in diabetic than in non-diabetic pregnancies, indicating a higher placental vascular resistance in the former group. The high umbilical artery PI occurred in fetuses who later developed distress in labor. Therefore, a high umbilical artery PI cannot be considered characteristic of diabetic pregnancy, although fetal distress might be more common in diabetic pregnancy. In addition, a high aortic volume flow was found in those fetuses who later develop distress in labor. This might be an expression of an early compensatory mechanism for increased placental vascular resistance. No specific flow variation was observed for any White class, or in association with hypertension or non-optimally regulated diabetes. The blood flow variables in growth-accelerated fetuses were comparable to those found in fetuses with normal weight. Since fetal distress might be more common in diabetic pregnancy, ultrasonic fetal blood flow measurements are recommended for antenatal fetal surveillance.