Risk of Adverse Neonatal Events in Pregnancies Complicated by Severe Maternal Morbidity.

Objective: To investigate the risk of adverse neonatal events after a pregnancy complicated by severe maternal morbidity.

Study Design: We analyzed a population-based cohort of deliveries in Quebec, Canada, between 2006 and 2021. The main exposure measure was severe maternal morbidity, comprising life-threatening conditions such as severe hemorrhage, cardiac complications, and eclampsia. The outcome included adverse neonatal events such as very preterm birth (gestational age <32 weeks), bronchopulmonary dysplasia, hypoxic ischemic encephalopathy, and neonatal death. Using log-binomial regression models, we estimated adjusted relative risks (RRs) and 95% confidence intervals (CIs) for the association between severe maternal morbidity and adverse neonatal events.

Results: Among 1 199 112 deliveries, 29 992 (2.5%) were complicated by severe maternal morbidity and 83 367 (7.0%) had adverse neonatal events. Severe maternal morbidity was associated with 2.96 times the risk of adverse neonatal events compared with no morbidity (95% CI 2.90-3.03). Associations were greatest for mothers who required assisted ventilation (RR 5.86, 95% CI 5.34-6.44), experienced uterine rupture (RR 4.54, 95% CI 3.73-5.51), or had cardiac complications (RR 4.39, 95% CI 3.98-4.84). Severe maternal morbidity was associated with ≥3 times the risk of neonatal death and hypoxic-ischemic encephalopathy and ≥10 times the risk of very preterm birth and bronchopulmonary dysplasia.

Conclusions: Severe maternal morbidity is associated with an elevated risk of adverse neonatal events. Better prevention of severe maternal morbidity may help reduce burden of severe neonatal morbidity.