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.

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 and in-patient stays for Massachusetts residents during 2002-2011. We excluded deliveries to women with preexisting chronic conditions for a final sample of 685,228 deliveries. Multivariable log binomial regression with generalized estimating equations modeled the relative risk 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 inpatient encounter and 1.0% at least one observational stay encounter. The adjusted relative risk of any inpatient encounter for deliveries with SMM was 2.48 (95% CI: 2.20-2.80) within 6 weeks postpartum and 2.04 (95% CI: 1.87-2.23) within 1 year. For observational stay encounters, adjusted relative risks 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.