Fetal Biometry and Doppler Study for the Assessment of Perinatal Outcome in Stage I Late-Onset Fetal Growth Restriction.

OBJECTIVE: To compare perinatal outcomes on fetuses classified as stage I late-onset fetal growth restriction (FGR) depending on the estimated fetal weight (EFW) centile category and the fetal and maternal Doppler study.

MATERIAL AND METHODS: Retrospective cohort study on 131 cases of stage I late-onset FGR (diagnosis ≥32+0 weeks), defined as: EFW < 3rd centile and normal Doppler (G1) or EFW < 10th centile and mean uterine artery pulsatility index (PI) > 95th centile (G2) or EFW < 10th centile and mild fetal Doppler alteration: umbilical artery PI > 95th centile, middle cerebral artery PI < 5th centile, or cerebroplacental ratio < 5th centile (G3). All groups were compared to their perinatal results.

RESULTS: There were 37, 30, and 64 cases in G1, G2, and G3, respectively. G1 and G2 showed lower percentages of cesarean section when compared with G3 (18.4, 22.5, and 45.3% (p < 0.01), respectively), being attributable to an excess of cesarean sections for non-reassuring fetal status. These differences remained when definitive birth weight centile was above that considered to define FGR, being 5.9, 12.5, and 41.8% (p < 0.01), respectively.

DISCUSSION: In stage I late-onset FGR fetuses, abnormal fetal Doppler is associated with a poorer tolerance to vaginal delivery, even when the birth weight is > 10th centile.