218: Risk of severe maternal morbidity associated with twin pregnancy: A population-based study in France

Abstract

Although twin pregnancy is associated with an increased incidence of obstetric complications, the maternal outcomes in this context, in terms of severe health alteration and organ dysfunction, are not well documented, which contrasts with the affluence of the literature on associated neonatal morbidity and mortality. Our objective was to investigate the association between twin pregnancy and severe acute maternal morbidity (SAMM) and to explore the contribution of cesarean delivery as an intermediate factor in this association. Population-based cohort-nested case-control study. Data source was the EPIMOMS prospective study, specifically designed to study SAMM, conducted in 6 French regions in 2012-2013 (N=182 309 deliveries). Cases were all women with a SAMM event between 22 wg and 42 days post-partum according to a definition obtained through a national formal consensus process (N=2500). Controls were 3650 randomly selected women who delivered without SAMM. Causal assumptions between twin pregnancy, SAMM and covariates were represented using a directed acyclic graph (Figure 1). The association between twin pregnancy and SAMM was analyzed with multivariate multilevel logistic regression. Contribution of cesarean delivery as an intermediate factor was assessed by path analysis. The incidence of SAMM was 1.3% [95%CI:1.2-1.3] in women with singleton pregnancy, and 6.1% [95%CI:5.3-7.0] in women with twin pregnancy (p<0.01). The proportion of twin pregnancies was 7.9% in cases and 1.6% in controls (p<0.01). After controlling for confounders, the risk of SAMM was significantly higher in twin than in singleton pregnancies (adjusted OR=4.2 [95%CI:3.1-5.8]). The association was also found for the most severe near-misses cases (adjusted OR=5.1 [95%CI:3.5-7.4]). In path analysis, 35.4% of the total risk of SAMM associated with twin pregnancy was mediated by cesarean (Table 1). After controlling for confounders, the risk of SAMM was multiplied by 4 in twin pregnancies. About one-third of the association between twin pregnancy and SAMM was mediated by cesarean delivery. Future analyses of other possible intermediate factors will further increase the understanding of the severe maternal risks associated with twin pregnancy.View Large Image Figure ViewerDownload Hi-res image Download (PPT)