36 Risk factors and outcomes of preeclampsia in twin pregnancies

Abstract

Introduction Pre-eclampsia (PE) is associated with significant maternal and perinatal mortality and morbidity. Twin pregnancy is at greater risk than singleton for developing PE. It is, however, unclear which risk factors are most strongly associated with the development of PE in a twin gestation. Objectives To establish the risk factors for PE in twin pregnancies and investigate the perinatal outcomes in these complicated pregnancies. Methods This was a cohort study of twin pregnancies cared for at St George’s University Hospital (SGH), London. Maternal, foetal and neonatal data were obtained from the hospital’s computerised database and maternity records. The diagnosis of PE was made following the ISSHP diagnostic criteria. Maternal risk factors were assessed at booking. Pregnancies complicated by aneuploidy, major structural abnormalities, miscarriage and those ending in termination were excluded from the analysis. The statistical analysis was performed using Mann–Whitney U and Chi-square tests for the comparison between the pregnancies that developed PE and those that did not. Logistic regression analyses were performed to identify and adjust for potential confounders. Results A total of 1250 twin pregnancies (2500 fetuses) were included in the analysis [284 (22.72%) were monochorionic and 966 (77.28%) dichorionic]. Of these, 120 (9.6%) were complicated by PE. While univariable analysis found that nulliparity (OR = 0.1.69, 95%CI = 1.13–2.52, p = 0.010), maternal age ⩾40 years (OR = 0.47, 95%CI = 0.27–0.81, p = 0.006), body mass index (BMI) (OR = 1.05, 95%CI = 1.02–1.09, p = 0.004) and chronic hypertension (OR = 3.02, 95%CI = 1.45–6.30, p = 0.003) were significant risk factors for the development of PE, multivariable logistic regression analysis found that only BMI (aOR = 1.06, 95%CI = 1.02–1.10, p = 0.002), chronic hypertension (aOR = 3.13, 95%CI = 1.44–6.79, p = 0.004), and nulliparity (aOR = 1.85, 95%CI = 1.19–2.89, p = 0.007) were independent risk factors for PE in a twin gestation. Chorionicity was not associated with the risk of developing PE (p = 0.772) compared to normotensive twin pregnancies. Those complicated by PE were more likely to have a number of adverse pregnancy outcomes, including induction of labour (66% vs 47.9%, p = 0.017), emergency Caesarean delivery (38.3% vs 19.4%, p Conclusions Nulliparity, increased maternal BMI and chronic hypertension were risk factors for PE in twin pregnancies, while monochorionicity, ethnicity and assisted reproductive techniques were not. In common with singleton pregnancies, twin pregnancies complicated by PE are at greater risk of an adverse pregnancy outcome. Prediction models for PE in twin pregnancies are likely to include risk factors that differ from those used in singleton pregnancy models.