Perinatal Outcomes in Appropriately Grown Monochorionic Diamniotic Twins With Intermittent Absent and Reversed End-Diastolic Umbilical Artery Flow Compared to Selective Fetal Growth Restriction Type III.

Objectives: Umbilical artery Doppler intermittent absent and reversed end-diastolic flow (iAREDF) is associated with increased perinatal morbidity and mortality in monochorionic twins with selective fetal growth restriction. The clinical significance of umbilical artery iAREDF in appropriately grown monochorionic twins is not well described.

Methods: This is a single-institution retrospective cohort study describing characteristics and outcomes of monochorionic diamniotic twins with appropriate for gestational age growth and umbilical artery iAREDF in comparison to monochorionic diamniotic twins with selective fetal growth restriction and iAREDF, or sFGR type III. The cohorts were compared for antenatal resolution of iAREDF, estimated gestational age at delivery, fetal and maternal complications, delivery characteristics, and survival outcomes.

Results: Ten appropriately grown monochorionic diamniotic twin pairs with umbilical artery iAREDF and 23 with sFGR Type III delivered at a mean gestational age of 30.4 (± 5) weeks and 30.7 (± 4) weeks, respectively (p = 0.93). No significant differences were observed in the Doppler course (deterioration or improvement) prior to delivery, fetal or maternal complications, delivery characteristics (with the exception of the persistence of the growth differences), or survival outcomes between groups.

Conclusions: Monochorionic diamniotic twins with intermittent absent and reversed end-diastolic umbilical artery velocity may be at increased risk for adverse perinatal outcomes even if criteria for selective fetal growth restriction are not met.