Umbilical Artery Doppler Study as a Predictive Marker of Perinatal Outcome in Preterm Small for Gestational Age Infants

PURPOSE To evaluate the merit of umbilical artery Doppler study as a predictive marker of perinatal outcome in preterm small for gestational age (SGA) infants. MATERIALS AND METHODS A total of 218 patients at 27 - 36 weeks of gestational age (GA) who received antenatal umbilical artery Doppler velocimetry and delivered singleton infants with SGA. The ratio of peak-systolic to end-diastolic blood flow velocities (S/D) in the umbilical artery was measured in each patient. The patients were divided into 3 groups: the normal group with S/D ratios of less than 95th percentile (n = 134), elevated S/D ratio group of 95th or more percentile (n = 41), and those with absent/reversed end diastolic flow (n = 43). Maternal characteristics and neonatal outcomes of these groups were comparatively analyzed. RESULTS The gestational age (GA) at the time of diagnosis of SGA, the mean GA at delivery, and the mean birth weight showed statistically significant difference among three groups (p < 0.001). Also, poor perinatal outcome was significantly increased in infants with abnormal S/D ratio (13.4% vs. 31.7% vs. 67.4%, p < 0.001). Multivariate logistic regression analysis revealed umbilical artery Doppler study as a significant independent factor for prediction of poor perinatal outcome (odds ratio: 3.7, 95% confidence interval 1.4 - 9.5, p = 0.007). CONCLUSION Antenatal umbilical artery Doppler velocimetry is shown as a significantly efficient marker in predicting perinatal outcome in preterm SGA infants.