Doppler velocimetry of the umbilical artery as a predictor of pregnancy outcome in pregnancies characterized by elevated maternal serum alpha-fetoprotein and normal amniotic fluid alpha-fetoprotein.

Objective: Women with elevated maternal serum alpha-fetoprotein (MSAFP) and normal amniotic fluid alpha-fetoprotein (AFAFP) are at an increased risk of an adverse pregnancy outcome. Such MSAFP elevations are probably the consequence of transplacental leakage caused by placental abnormalities. These may result in disturbed bloodflow through placental vessels. The purpose of this study was to assess whether measurement of such disturbances by Doppler velocimetry of the umbilical artery has a predictive value for pregnancy outcome.

Study Design: The study group consisted of 85 patients, in whom the only finding was elevated maternal serum alpha-fetoprotein. Systolic/diastolic (S/D) ratios were calculated using a continuous wave Doppler measurement of the umbilical artery, performed at 6 to 8-week intervals. Serial results for each individual were incorporated into a single 'Velocimetry Score'.

Results: In group B (14 patients) with an abnormally elevated umbilical S/D ratio, a higher incidence of intrauterine growth retardation (42.9%), preterm deliveries (78.6%), and fetal loss (42.9%) was noted, as compared with group A (71 patients) with a normal S/D ratio.

Conclusions: Umbilical artery Doppler velocimetry may serve as a predictor of pregnancy outcome in the high-risk group characterized by elevated MSAFP.