Medicaid expansions under the Affordable Care Act have increased insurance coverage and prenatal care utilization in low-income women. However, it is not clear whether they are associated with any measurable improvement in maternal health outcomes. In this study, we compared the changes in the incidence of severe maternal morbidity (SMM) during delivery hospitalizations between low- and high-income women associated with the 2014 Medicaid expansion in New York State.
Data for this retrospective cohort study came from the 2006–2016 New York State Inpatient Database, a census of discharge records from community hospitals. The outcome was SMM during delivery hospitalizations, as defined by the Centers for Disease Control and Prevention. We used regression coefficients (β) from multivariable logistic models: (1) to compare independently in low-income women and in high-income women the changes in slopes in the incidence of SMM before (2006–2013) and after (2014–2016) the expansion, and (2) to compare low- and high-income women for the changes in slopes in the incidence of SMM before and after the expansion.
A total of 2,286,975 delivery hospitalizations were analyzed. The proportion of Medicaid beneficiaries in parturients increased a relative 12.1% (95% confidence interval [CI], 11.8-12.4), from 42.9% in the preexpansion period to 48.1% in the postexpansion period, whereas the proportion of the uninsured decreased a relative 4.8% (95% CI, 2.8-6.8). Multivariable logistic modeling revealed that implementation of the 2014 Medicaid expansion was associated with a decreased slope during the postexpansion period both in low-income women (β = –0.0161 or 1.6% decrease; 95% CI, –0.0190 to –0.0132) and in high-income women (β = –0.0111 or 1.1% decrease; 95% CI, –0.0130 to –0.0091). The decrease in slope during the postexpansion period was greater in low- than in high-income women (β = –0.0042 or 0.42% difference; 95% CI, –0.0076 to –0.0007).
Implementation of the Medicaid expansion in 2014 in New York State is associated with a small but statistically significant reduction in the incidence of SMM in low-income women compared with high-income women.