Selective IUGR in dichorionic twins: what can Doppler assessment and growth discordancy say about neonatal outcomes?

The aim of the present study was to assess, in a population of dichorionic twin pregnancies with selective growth restriction, the effect of inter-twin differences by use of Doppler velocimetry and fetal growth discordancy on perinatal outcomes. This was a retrospective study including dichorionic twin pregnancies from January 2008 to December 2015 at the Department of Obstetrics and Gynecology of Fondazione MBBM. Only dichorionic twin pregnancies affected by selective intrauterine growth restriction (IUGR) delivering at ≥24 weeks were included in the study. We found that twin pregnancies with inter-twin estimated fetal weight (EFW) discordance ≥15% were significantly associated with a higher risk of preterm delivery before 32 (P=0.004) and 34 weeks (P=0.04). Similarly, twin pregnancies with inter-twin abdominal circumference (AC) discordance ≥30° centiles were associated with a higher rate of neonatal intensive care unit (NICU) admission (P=0.02), neonatal resuscitation (P=0.02) and adverse neonatal composite outcome (P=0.04). Of interest, when comparing twin pregnancies according to Doppler study, growth restricted twins had a higher rate of composite neonatal outcome and in multivariate analysis, an abnormal Doppler was an independent risk factor for this outcome. Our study associated growth discrepancy with specific pregnancy outcomes, according to defined cut-offs. In addition, we demonstrated that an abnormal umbilical artery Doppler is independently associated with a composite neonatal adverse outcome in growth restricted fetuses