Preeclampsia in twin pregnancies: association with selective intrauterine growth restriction

Objective: To identify the association between preeclampsia (PE) and selective intrauterine growth restriction (sIUGR) in twin pregnancies.Methods: This was a retrospective cohort study of 1004 twin pregnancies from 2008 to 2014. We specifically compared the incidence, clinical characteristics and outcomes of PE between sIUGR and normal-growth twin pregnancies.Results: PE occurred more frequently in sIUGR pregnancies [29.0% (51/176)] than in normal-growth twin pregnancies [13.1% (99/756), p<0.001, adjusted odds ratio 3.29]. Among sIUGR, the incidence of PE was significantly higher in dichorionic (DC) pregnancies (37.5%, 30/80) than in monochorionic (MC) pregnancies (21.9%, 21/96). The rates of onset at <32 weeks (p=0.045) and of severe PE (p=0.025) were higher in sIUGR pregnancies with PE. The systolic blood pressure was also higher in sIUGR pregnancies with PE (152.611.8mmHg) than in normal-growth pregnancies with PE (148.0 +/- 8.2mmHg) (p=0.042). Additionally, more sIUGR pregnancies were delivered at 32-36 weeks (p=0.001), and fewer were delivered at 36 weeks (p<0.001). Moreover, the prevalence of severe neonatal asphyxia was higher in sIUGR pregnancies with PE than in normal-growth pregnancies with PE (8.8% versus 2.5%, p=0.020).Conclusions: sIUGR is associated with increased odds of developing severe PE in twin pregnancies, leading to poorer perinatal outcomes.