Relationship Between Maternal Death and Infant Outcomes in a Longitudinal, Population-Based Dataset

To estimate the association between pregnancy-associated death or severe maternal morbidity and infant outcomes.

We conducted a retrospective cohort study using Massachusetts statewide data from 1999 to 2021. The dataset included hospital records longitudinally linked to births and maternal and infant death records. The primary exposures were pregnancy-associated death (deaths during pregnancy or in the year postpartum), severe maternal morbidity, and pregnancy-associated death after severe maternal morbidity. The main outcomes were infant death in the first year and, for those infants who survived, hospitalization in the first year of life. Bivariate and robust Poisson regression analyses through generalized estimating equations regression were used to estimate the association between the exposures and outcomes.

Of 1,617,054 live births in Massachusetts between 1999 and 2020, there were 474 pregnancy-associated deaths. Pregnancy-associated death ratios were highest among individuals who were aged 40 years or older (49.3/100,000), who were non-Hispanic Black (43.0/100,000), who had public insurance (51.1/100,000), or who had a parity of four or more (80.6/100,000). Among individuals experiencing severe maternal morbidity (745.3/100,000), those who had a hospital encounter associated with opioid use (721.2/100,000) or a documented prepregnancy comorbidity (200.7/100,000) had the highest pregnancy-associated death ratios. In cases of pregnancy-associated death, the infant mortality rate per 1,000 live births was 55.0 (95% CI, 34.9-75.2) compared with 4.0 (95% CI, 3.9-4.1) when the mother survived. When the pregnancy-associated death followed severe maternal morbidity, the infant mortality rate was 87.9 per 1,000 live births (95% CI, 29.7-146.1). After a pregnancy-associated death, when a full-term infant survived to 1 year of age, there was a 35% greater likelihood of rehospitalization in the first year of life (adjusted risk ratio 1.35, 95% CI, 1.01-1.82) than when the mother did not die.

Pregnancy-associated death was associated with infant death and worse health of surviving children in the first year of life, further demonstrating the far-reaching consequences of maternal deaths and the clear link between maternal and infant health.