Estimated weight centile as a predictor of perinatal outcome in small-for-gestational-age pregnancies with normal fetal and maternal Doppler indices.

Objective: To evaluate the risk of adverse perinatal outcome according to estimated fetal weight (EFW) in a cohort of term small-for-gestational-age (SGA) pregnancies with normal umbilical, fetal middle cerebral and maternal uterine artery Doppler indices.

Methods: A cohort of 132 term SGA fetuses with normal umbilical artery pulsatility index (PI), mean uterine artery PI and cerebroplacental ratio was compared to a control group of 132 appropriate-for-gestational-age babies, matched by gestational age at delivery. The capacity of the EFW percentile to predict Cesarean delivery, Cesarean delivery for non-reassuring fetal status (NRFS), neonatal acidosis and days of neonatal hospitalization was analyzed.

Results: As a whole, SGA fetuses with normal Doppler findings did not show a statistically significant difference for intrapartum Cesarean delivery (22.0 vs. 15.9%; P = 0.21) and neonatal acidosis (3.3 vs. 1.5%; P = 0.30), but had significantly higher risk for Cesarean delivery for NRFS (15.9 vs. 5.3%; P < 0.01) and longer neonatal hospitalization (1.39 vs. 0.87 days; P < 0.05) than did controls. SGA fetuses with EFW < 3(rd) centile had a significantly higher incidence of intrapartum Cesarean delivery (30.0 vs. 15.3%; P = 0.04), Cesarean delivery for NRFS (25.0 vs. 8.3%; P < 0.01) and longer neonatal hospitalization (2.0 vs. 0.9 days; P < 0.01) than those with EFW ≥ 3(rd) centile. SGA cases with EFW ≥ 3(rd) centile had perinatal outcomes similar to those of controls with normal EFW.

Conclusion: Among SGA fetuses with normal placental and cerebral Doppler ultrasound findings, EFW < 3(rd) centile discriminates between those with a higher risk for adverse perinatal outcome and those with outcomes similar to those of normally grown fetuses.