Severe Maternal Morbidity at Delivery and Risk of Hospital Encounters Within 6 Weeks and 1 Year Postpartum.

Background: Little is known about the impact of severe maternal morbidity (SMM) after delivery. We examined the risk of rehospitalization in the first year postpartum among deliveries to women with and without SMM. Materials and Methods: We used the Pregnancy to Early Life Longitudinal data system, in which vital birth/fetal death records were linked with hospital delivery discharge data and subsequent nondelivery hospitalization data, including observational stays (OSs) and in-patient stays (hospital discharge [HD]) for Massachusetts residents during 2002-2011. We excluded deliveries to women with preexisting chronic conditions: hypertension, diabetes, asthma, and autoimmune conditions for a final sample of 685,228 deliveries. Multivariable log binomial regression with generalized estimating equations modeled the relative risk (RR) of hospital encounters 6 weeks and 1 year postpartum. Results: The rate of SMM was 99 per 10,000 deliveries. In the first year postpartum, 2.8% of deliveries to women without chronic medical conditions experienced at least one HD encounter and 1.0% at least one OS encounter. The adjusted relative risk (aRR) of any HD encounter for deliveries with SMM was 2.48 (95% confidence interval [CI]: 2.20-2.80) within 6 weeks postpartum and 2.04 (95% CI: 1.87-2.23) within 1 year. For OS encounters, aRRs among deliveries with SMM at delivery were 2.47 (95% CI: 1.94-3.14) in the first 6 weeks and 1.69 (95% CI: 1.43-2.01) in 1 year. Conclusions: In Massachusetts, SMM increased the risk of rehospitalization in the first year postpartum among deliveries to women without chronic medical conditions.