Reduced Postpartum Hospitalizations After Medicaid Expansion

According to a study published in Health Affairs, Medicaid expansions under the Affordable Care Act (ACA) were associated with a decrease in postpartum hospitalizations, suggesting that expanding Medicaid coverage improved postpartum health for low-income birthing people. 

Experts suggest that improving access to health care before pregnancy and in the postpartum period is essential for the well-being of US childbearing parents and their infants, said researchers. Despite Medicaid providing coverage for more than 40% of births in the US and offering 60 days of postpartum coverage, uninsured rates remain high for women during the 2 to 6 months post-pregnancy. However, states that implemented the ACA Medicaid expansions saw an increase in eligibility for low-income adults, resulting in improved Medicaid enrollment and insurance coverage for parents before and after pregnancy. 

Previous research found increased outpatient care utilization under the ACA Medicaid expansions and improved care during pregnancy. This study sought to examine if those improvements in access to care affected inpatient hospitalization rates. 

The analysis utilized data from 2010 to 2017, which was obtained from the Agency for Healthcare Research and Quality's Healthcare Cost and Utilization Project State Inpatient Databases. These databases encompassed all the inpatient hospital records within each state. The study included states with patient identifiers available during both the pre-pregnancy and post-pregnancy periods, enabling the tracking of patients across hospital encounters. 

Data was specifically pulled from the expansion states Iowa, Maryland, New Mexico, and Washington and nonexpansion states of Florida, Georgia, Mississippi, and Utah. States with non-ACA Medicaid expansions for low-income adults and states with changes in Medicaid-funded deliveries unrelated to the expansions were excluded. 
The post expansion period began on the start date of Medicaid expansion implementation in each state, which was January 1, 2014. Medicaid expansion applied to adults without children and parents, although the change in eligibility varied depending on parental status. In most states, adults without children were generally not eligible for Medicaid, regardless of their income level, so the change in preconception eligibility after Medicaid expansion relied on whether the birthing person had other children before becoming pregnant. In expansion states, income eligibility for childless adults increased from 0% to 138% of the federal poverty level. Additionally, parental eligibility increased from 80% to 138% in Iowa, 122% to 138% in Maryland, 85% to 138% in New Mexico, and 71% to 138% in Washington. There was no data on whether postpartum individuals had other children before delivery.

The study sample consisted of individuals 19 years or older who were residents of the respective states and had a hospital delivery where Medicaid is the primary payer. In addition to analyzing the effects for all patients meeting the defined criteria, the sample was stratified based on race and ethnicity.

Time periods were categorized to differentiate between the period already covered by pregnancy-related Medicaid and the newly covered period in expansion states. The sample was restricted to patients whose outcomes could be observed within a calendar year. The first group had deliveries during the first 3 quarters of each calendar year for the 60 postpartum outcomes, while the second group had deliveries during the first 2 quarters for the 61 days to 6 months postpartum outcome. The International Statistical Classification of Diseases and Related Health Problems categorized the primary diagnoses for postpartum hospitalizations. 

The average rates of postpartum hospitalization before and after expansion in the expansion and nonexpansion states were tested for statistically significant changes in hospitalization rates using a mean comparison test and evaluated significance at different levels. Various models were used, including an event study model, a difference-in-differences model that was adjusted for covariates, and linear regression models with clustered standard errors by state.

Previous research indicates that hospitalizations are significantly more common among postpartum women in the first 21 days after childbirth than nonpostpartum women. Still, the difference between the 2 groups became smaller later in the postpartum period. The study found that only 8% of hospital admissions after 60 days for postpartum people with Medicaid-financed deliveries were related to childbirth, and there were nearly twice as many overall hospitalizations during the first 60 days compared to the period between 61 days and 6 months postpartum. 

A 17% decrease in 60-day postpartum hospitalizations among people with Medicaid-financed deliveries in states with ACA Medicaid expansions was noted compared to non-expansion states. The findings also show declines in childbirth-related and non-childbirth-related hospitalizations, suggesting that Medicaid expansions affected all hospitalizations. Higher rates of postpartum hospitalizations were observed among non-Hispanic and Black individuals. 

“This study provides the first evidence of a decrease in postpartum hospitalizations associated with expanded Medicaid,” said researchers. “Our findings suggest that ongoing efforts to expand Medicaid may contribute to better postpartum health for US birthing people.” 

Reference: 
Steenland S, Wherry L. Medicaid expansion led to reductions in postpartum hospitalizations. Health Affairs. Published online January 9, 2023. doi:10.1377/hlthaff.2022.00819