Doppler Velocimetry of the Umbilical Artery as a Predictor of Outcome in Pregnancies Characterized by Elevated Beta-Subunit Human Chorionic Gonadotropin

Abstract

Women with unexplained elevated maternal serum beta-subunit human chorionic gonadotropin (beta-HCG) are at an increased risk for adverse pregnancy outcome, most likely due to placental abnormalities. Such abnormalities may also result in disturbed blood flow through placental vessels. The purpose of this study was to assess whether Doppler velocimetry of the umbilical artery has a predictive value for pregnancy outcome in patients with unexplained elevated maternal serum beta-HCG. The study group included 63 patients, in whom the only finding was elevated maternal serum beta-HCG. Systolic/diastolic (S/D) ratios were calculated using a continuous wave Doppler measurement of the umbilical artery, performed beginning at 22 weeks of gestation and followed at 6- to 8-week intervals. Serial results for each individual were incorporated into a single 'velocimetry score', calculated as the rate of abnormal velocimetry measurements. beta-HCG was found to be associated with poor pregnancy outcome: including intrauterine growth restriction (IUGR) (19%), pregnancy-induced hypertension (PIH) (14%), and preterm labor (PTL) (19%). Patients were then divided into 2 groups according to their velocimetry score: group A, VS < or = 80 (n = 47), and group B, VS > 80 (n = 16). A low velocimetry score was associated with a higher rate of IUGR, PIH, and a significantly higher rate of PTL. Umbilical artery Doppler velocimetry may serve as a predictor of pregnancy outcome in the high-risk group characterized by unexplained elevated beta-HCG.