Predictors of poor outcomes in monochorionic diamniotic twin pregnancies complicated by selective fetal growth restriction.

INTRODUCTION: To identify predictors of poor outcomes in monochorionic diamniotic twin (MCDA) pregnancies with selective fetal growth restriction (sFGR) irrespective of the umbilical artery (UA) Doppler abnormalities.

METHODS: Single center retrospective analysis of MCDA twins diagnosed with sFGR that opted for expectant management between 2010-2021. The presence of any of the following variables in the growth restricted fetus: low amniotic fluid volume (DVP≤2cm), lack of a cycling bladder, absent or reversed flow in the ductus venosus (DV) with atrial contraction and elevated middle cerebral artery peak systolic velocity (MCA-PSV) defined as ≥1.50 multiples of the median was categorized as complicated. sFGR cases were classified as simple in the absence of the above-mentioned variables.

RESULTS: 63.3% cases qualified as simple and 36.7% were complicated. Intertwin EFW discordance was higher in the complicated category (26% vs 33%, p=0.0002). The median gestational age at delivery was earlier (33 weeks vs 30.5 weeks, p=0.002) and the likelihood of survival was lower in the complicated category (p<0.0001). The likelihood of two survivors to discharge was lower in type I complicated cases (70% in complicated type I versus 97.1% in simple type I, p=0.0003). On logistic regression analysis, an increase in the "complicated" score negatively correlated with two survivors to discharge (p<0.0001). An ROC curve was created, and the AUC was 0.79. Increasing intertwin EFW discordance also decreased the probability of two survivors to discharge.

CONCLUSION: The presence of oligohydramnios, lack of a cycling bladder, abnormal DV Doppler, and elevated MCA-PSV in the growth restricted fetus is associated with poor perinatal outcomes and a lower likelihood of having two survivors to discharge. The addition of intertwin EFW discordance to these variables helped improve the survival predictability.