Comparison of Delivery-Related, Early and Late Postpartum Severe Maternal Morbidity Among Individuals With Commercial Insurance in the US, 2016 to 2017

This cross-sectional study assesses the relative rates and characteristics of early and late postpartum severe maternal morbidity overall and among racial and ethnic groups and individuals with perinatal mood and anxiety disorder.


Introduction
The rate of late postpartum deaths is substantial in the US compared with other countries. 1 Similar to maternal mortality occurring during and shortly after pregnancy, a 2019 report indicated that non-Hispanic Black individuals had the highest risk for late postpartum deaths in the US. 2 Leading causes of late postpartum deaths differ from those occurring earlier in the perinatal period, with a large proportion resulting from underlying perinatal mood and anxiety disorders (PMADs). 3 Severe maternal morbidity (SMM) is considered proximate to maternal mortality because without identification and treatment, these conditions would lead to maternal death in some cases. Studies often assess SMM at birth and early postpartum to develop strategies to prevent maternal mortality.
This study assessed relative rates and characteristics of SMM occurring late postpartum overall, by race and ethnicity, and among those diagnosed with PMADs.

Methods
This cross-sectional study of deidentified data was considered exempt from review by the University of Michigan Institutional Review Board. The study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline.
Data were analyzed from December 14, 2020, to October 7, 2021. Using deidentified claims data from the Optum Clinformatics Data Mart (Optum) for 2016 to 2017, we evaluated rates of SMM with and without blood transfusion during 3 pregnancy periods, including hospitalization for birth, hospital discharge to 42 days postpartum, and 43 to 365 days postpartum, among individuals aged 15 to 44 years. We restricted the sample to individuals with continuous enrollment in a single employer-based health plan for at least 1 year before and 1 year after a live birth. For individuals with more than 1 delivery in the 2-year period, we focused only on the index delivery. We identified SMM using diagnosis and procedure codes described by the US Centers for Disease Control and Prevention. 4 Race and ethnicity were determined based on classifications provided in the Optum database (ie, Asian, Black, Hispanic, White, and unknown/missing), and PMADs were identified in delivery records. 5 We assessed rates of SMM with and without blood transfusion in each period using logistic regression models with predictive margins adjusted for age, insurance plan type, region, obstetric comorbidity, 6 race and ethnicity, and PMADs. Cluster-based standard errors accounted for heteroskedasticity across insurance plans. We performed all analyses (2-sided test, α = .05 threshold) using SAS version 9.4 (SAS Institute Inc) and Stata version 14.1 (StataCorp LLC).

Discussion
The most common SMM indicators early and late postpartum included severe anesthesia complications and sepsis. Black individuals had the highest rates of SMM in each pregnancy period compared to individuals from other racial and ethnic groups. In contrast with trends in the overall population, individuals with PMADs experienced a markedly sustained risk for SMM early and late postpartum, which should inform clinical and policy strategies to address and prevent maternal morbidity and mortality among this population.
Limitations of this study include the following: the focus on live births rather than other pregnancy outcomes; the limited generalizability of a study population with continuous commercial insurance coverage during the postpartum year; the inability to measure death as a competing outcome, given the low sample size; issues inherent with using the race and ethnicity categories provided in the Optum database; and the inability to measure racism. Nonetheless, our findings suggest that racial and ethnic inequities are associated with SMM in the postpartum year and that SMM is particularly elevated among individuals with PMADs. Role of the Funder/Sponsor: The funders had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.