Abstract
Background
Severe maternal morbidity is associated with substantially increased risks of adverse neonatal outcomes. However, few studies have assessed the association between severe maternal morbidity and adverse pregnancy, delivery, and perinatal outcomes in the subsequent delivery.
Objective
We aimed to investigate the association between severe maternal morbidity and its specific types in the first delivery and the risk of adverse pregnancy, delivery, and neonatal outcomes in the second delivery.
Study design
We examined 2 population-based cohorts in Sweden and British Columbia, Canada, of mothers with both their first and second delivery recorded. The primary exposure was severe maternal morbidity in the first delivery (recorded during pregnancy, delivery or within 42 days postpartum). The outcomes were pregnancy and delivery complications, and offspring composite severe neonatal morbidity, and perinatal mortality (ie, stillbirths or neonatal deaths) within the first 28 days after birth, in the second delivery. We used multivariable generalized linear models to obtain adjusted risk ratios and 95% confidence intervals, adjusted for confounders.
Results
In both Sweden and British Columbia, women who experienced severe maternal morbidity in their first delivery had an increased risk of composite perinatal death/severe neonatal morbidity in the second delivery (Sweden: adjusted risk ratio, 1.88; 95% confidence interval, 1.75–2.02, British Columbia: adjusted risk ratio, 1.49; 95% confidence interval, 1.24–1.79), compared with mothers without severe maternal morbidity in the first delivery. In Sweden, second deliveries to women who had severe maternal morbidity in their first delivery were associated with a 1.59-times higher risk of stillbirth, a 1.65-times higher risk of neonatal mortality, a 1.95-times higher risk of composite severe neonatal morbidity, and 1.69-fold higher risk of infant mortality. In Sweden, compared with unaffected first delivery, severe maternal morbidity in the first delivery was associated with a 4.77-fold higher risk of severe maternal morbidity, 6.20-fold higher risk of preeclampsia, and an approximately 2-fold increased risk of placental abruption, maternal infection, antepartum hemorrhage, and postpartum hemorrhage in the second delivery. While in British Columbia, the adjusted estimates were in the same direction as in Sweden, statistical significance was reached for several outcomes, specifically, infant mortality, severe maternal morbidity, preeclampsia, gestational diabetes, placental abruption, antepartum hemorrhage, postpartum hemorrhage, and both elective and cesarean delivery in the second delivery.
Conclusion
In both Sweden and British Columbia, Canada, severe maternal morbidity in the first delivery was associated with an increased risk of adverse pregnancy, delivery, and offspring outcomes in the subsequent delivery. Our findings can guide clinical and reproductive counseling for women with a history of severe maternal morbidity.