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.
Keywords: Preterm small for gestational age infant; perinatal outcome; umbilical artery Doppler velocimetry.