Prior Hospitalization, Severe Maternal Morbidity, and Pregnancy-Associated Deaths in Massachusetts From 2002 to 2019

To examine demographic and clinical precursors to pregnancy-associated deaths overall and when pregnancy-related deaths are excluded.

We conducted a retrospective cohort study based on a Massachusetts population-based data system linking data from live birth and fetal death certificates to corresponding delivery hospital discharge records and a birthing individual's nonbirth hospital contacts and associated death records. Exposures included maternal demographics, severe maternal morbidity (without transfusion), hospitalizations in the 3 years before pregnancy, comorbidities during pregnancy, and opioid use. In cases of postpartum deaths, hospitalization between delivery and death was examined. The primary outcome measure was pregnancy-associated death , defined as death during pregnancy or up to 1 year postpartum.

There were 1,291,626 deliveries between 2002 and 2019, of which 384 were linked to pregnancy-associated deaths. Pregnancy-associated but not pregnancy-related deaths (per 100,000 deliveries) were highest for birthing people with opioid use before pregnancy (498.3), severe maternal morbidity (387.3), a comorbidity (106.3), or a prior hospitalization (88.9). In multivariable analysis, the adjusted risk ratios associated with severe maternal morbidity (9.37, 95% CI, 6.14-14.31) and opioid use (6.49, 95%, CI, 3.71-11.35) were highest. Individuals with pregnancy-associated deaths were also more likely to have been hospitalized before or during pregnancy (2.30, 95% CI, 1.62-3.26). Among postpartum deaths, more than two-thirds (69.9%) of birthing people had a hospital contact after delivery and before their death.

Severe maternal morbidity and opioid use disorder were precursors to pregnancy-associated deaths. Individuals with pregnancy-associated but not pregnancy-related deaths experienced a history of hospital contacts during and after pregnancy before death.