Leveraging a Longitudinally Linked Dataset to Assess Recurrence of Severe Maternal Morbidity

Among those with a severe maternal morbidity (SMM) event and a subsequent birth, we examined how the risk of a second SMM event varied by patient characteristics and intrapartum hospital utilization.

We used a Massachusetts population-based dataset that longitudinally linked in-state births, hospital discharge records, prior and subsequent births, and non-birth-related hospital utilizations for birthing individuals and their children from January 1, 1999, to December 31, 2018, representing 1,460,514 births by 907,530 birthing people. We restricted our study sample to 2,814 people who had their first SMM event associated with a singleton birth and gave birth a second time within the study period. Our outcome measure was recurrence of SMM in the second birth. We calculated the prevalence of SMM at second birth, compared SMM conditions between births, and estimated the adjusted risk ratios and 95% confidence intervals for having an SMM event at second birth among those who had an SMM at the first birth. We also examined overall hospital utilization including inpatient admissions, emergency room visits, and observational stays, and hospital utilization by interpregnancy intervals (IPIs) between the first and second birth.

There were 2,814 birthing people with at least one birth after the first SMM singleton birth. Among those, 198 (7.0%) had a subsequent SMM. The percentage of people with a second SMM event varied by age, race/ethnicity, insurance, IPI, and history of hypertension at first case of SMM (all p < .05). Between births, people with a second SMM event had significantly higher proportions of inpatient admissions (60.1% vs. 33.2.0%; p < .001), emergency room visits (71.7% vs. 57.7%; p < .001), and observational stays (35.4% vs. 19.5%; p < .001) compared with those who did not experience a second SMM event.

Hospital utilization after a birth with SMM might indicate an elevated risk of a second SMM event. Providers should counsel their patients about prevention and warning signs.