Is fetal sex associated with adverse maternal outcomes in twin pregnancy?

Aim: to estimate the relationship between fetal sex pairing on the risk of adverse maternal outcomes in twin gestation.
Methods: This study aimed at a retrospective analysis of all twin deliveries at British Columbia during a period of 10 years. This population-based study included 6,321 multiple-fetal gestations. The incidence of adverse maternal outcomes was described between three groups of fetal sex pairing: Male-male (2101 pairs, n=4,202), female-female (2053 pairs, n=4,106) and male-female (2,167 pairs, n=4,334) pairs. Regression analysis was used to predict the role of fetal gender on 16 adverse maternal outcomes.
Results: Association analysis suggest that length of stay in hospital, proteinuria, pregnancy induced hypertension, preeclampsia, antepartum haemorrhage, preterm birth, premature rupture of membrane and cesarean section were associated with sex pairing. Adjusting for confounding variables, multiple regression analysis substantiated these associations for postpartum length of stay longer than 3 days, proteinuria, pregnancy induced hypertension, preeclampsia and cesarean section.
Conclusions: Sex determination by ultrasound screening contributes to prediction of adverse maternal outcome and can improve clinical management of adverse maternal outcomes.