according to findings from the prospective EPIMOMS study.
The population-based incidence of severe acute maternal morbidity occurring between 22 weeks’ of gestation and 42 days post partum in the 2012-2013 French multicenter study was 6.2% among 3,202 twin pregnancies and 1.3% among 179,107 singleton pregnancies, Hugo Madar, MD, MPH, of Bordeaux University Hospital, France, and colleagues reported on behalf of the EPIMOMS (Epidémiologie de la Morbidité Maternelle Sévère) study group.
For the current analysis – a population-based, cohort-nested, case-control analysis of study data – the investigators compared 2,500 case patients (8% had twin pregnancies) and 3,650 controls (2% had twin pregnancies) who did not experience severe acute maternal morbidity during that time period (odds ratio, 4.7). After accounting for confounding factors, the increased risk among women with twin versus singleton pregnancies persisted (OR, 4.2) during both the antepartum (OR, 4.1) and intrapartum/postpartum (OR, 4.2) periods.
The majority of events (77%) occurred during the latter periods, and the two most common underlying causal conditions were severe obstetric hemorrhage (66%) and severe hypertensive complications (20%); however, the increased risk in twin pregnancies was apparent, regardless of the underlying cause.
The cesarean delivery rates for twin versus singleton pregnancies were 72% and 34%, respectively, in the case group, and 58% and 18%, respectively, in the control group. A path analysis taking potential indication bias into account showed that 21% of the total risk of intrapartum or postpartum severe acute maternal morbidity risk associated with twin pregnancy was mediated by cesarean delivery, Dr. Madar and associates noted, explaining that, “in other words, if twin pregnancies had the same probability of cesarean delivery as singleton pregnancies, the association found between twin pregnancy and intrapartum or postpartum severe acute maternal morbidity would be reduced by one-fifth.”
This provides further support for limiting the use of cesarean for twin deliveries to cases with clear medical indications, as increasing the rate of vaginal deliveries may decrease the rate of severe acute maternal morbidity, they concluded.
EPIMOMS was supported by the National Research Agency and the Ile de France Regional Health Agency. Dr. Madar received a training grant from the Aquitaine Regional Health Agency. The authors reported having no other relevant financial disclosures.
SOURCE: Madar H et al. Obstet Gynecol. 2019;133:1141-50.