Increased uterine artery pulsatility index at 34 weeks and outcome of pregnancy

Objectives To evaluate pregnancy outcome in patients with increased uterine artery (UtA) pulsatility at 34 weeks' gestation as an isolated finding. Methods Normotensive women attending at 34 weeks' gestation for fetal growth assessment were enrolled in the study if fetal growth was appropriate for age and mean UtA pulsatility index (PI) was persistently above the 95th centile for gestational age. Patients were excluded with any of the following conditions: multiple pregnancy, sonographic suspicion of fetal anomaly or fetal growth restriction, history of chronic maternal disease, hypertensive disorder or diabetes in the current pregnancy or one or more adverse events in their past obstetric history. The control group consisted of age- and body mass index-matched low-risk women attending at 34 weeks with normal uterine artery Doppler since the midtrimester. Results Sixty-six normotensive patients with normal fetal growth and increased UtA-PI at 34 weeks were included in the study group. Women with abnormal Doppler findings compared with controls showed significantly lower gestational age at delivery (38.2 ± 1.6 vs. 38.9 ± 1.3 weeks, P = 0.006), birth weight (2942 ± 583 vs. 3404 ± 469 g, P < 0.001), birth-weight Z-score (-0.61 ± 1.07 vs. 0.19 ± 1.05, P < 0.001) and increased risk of a small-for-gestational- age (SGA) newborn (13/66 vs. 1/66, P < 0.001). The occurrence of late pre-eclampsia (3/66 vs. 0/66, P = 0.24), admission to the neonatal intensive care unit (6/66 vs. 4/66, P = 0.74), rate of induction of labor (16/66 vs. 14/66, P = 0.83) and rate of Cesarean section due to fetal distress (6/66 vs. 3/66, P = 0.49) were comparable between the two groups. Conclusion Increased UtA-PI as an isolated finding at 34 weeks' gestation is associated with an increased risk of delivering an SGA neonate.