Aim: The goal of this study was to evaluate the umbilical and uterine Doppler velocimetry waveforms for predicting the perinatal outcome of low-risk pregnancies at term.
Methods: We prospectively recruited 514 women with low risk pregnancies and performed umbilical and uterine artery Doppler assessments between 37 and 41 weeks of gestation. Ultrasound measurements (completed in 365 patients) were correlated with the perinatal outcome.
Results: The velocimetry waveforms of the umbilical artery were significantly associated with birthweight, placental weight, and postpartal umbilical artery pH. Low pH, placental weight, and birthweight were correlated with increasing pulsatility index (PI) and resistance index (RI). An umbilical artery PI > 1.2 and a uterine artery RI > 0.5 were associated with statistically higher rates of infants that were small for gestational age (SGA). Also, high cesarean delivery rates were correlated with an umbilical artery PI > 1.2.
Conclusions: In our low-risk pregnancies population, the elevated umbilical artery indices at term appeared to be associated with the higher rates of infants that were SGA and cesarean deliveries. The Doppler waveforms at term had low prognostic value for predicting neonatal acidosis or decreased Apgar scores.