Umbilical artery Doppler velocimetry in fetuses with a single umbilical artery.

OBJECTIVE: Doppler waveform analysis of the umbilical artery is an important tool for the evaluation of high-risk pregnancies. Yet, available data are based on normal values from three-vessel umbilical cords. Our purpose was to evaluate the value of umbilical artery Doppler velocimetry in fetuses with a single umbilical artery. METHODS: One hundred thirteen consecutive singleton fetuses with a single umbilical artery between 16 and 40 weeks' gestational age were studied prospectively at a tertiary referral center for prenatal diagnosis and therapy. Complete follow-up was obtained from 103 cases. RESULTS: The systolic-diastolic ratio in the umbilical artery was abnormal in 31 fetuses (30%) and normal in 72 fetuses (70%). Fetuses with abnormal Doppler waveform analysis in the umbilical artery were significantly more likely to be growth restricted (55 compared with 15%), to have complex malformations (58 compared with 1%) or an abnormal karyotype (29 compared with 0%), or not to survive the fetal/perinatal period (42 compared with 0%) than those with normal Doppler waveform analysis. CONCLUSION: Fetuses with a single umbilical artery and abnormal umbilical Doppler velocimetry had a significantly increased risk of adverse fetal and neonatal outcome compared with those with a single umbilical artery but normal Doppler studies.