News Release

Medicaid expansion improved insurance stability for low-income pregnant women

Peer-Reviewed Publication

Columbia University's Mailman School of Public Health

Medicaid expansion improved the stability of insurance coverage for low-income women in the months leading up to and right after their baby's birth, according to a study at Columbia University Mailman School of Public Health. The findings showed that with the expansion of Medicaid, there was a 10- percentage-point decrease in women going uninsured or changing insurance plans in the time around their pregnancy. This is the first study to examine Medicaid's impact on the stability of insurance from before to after childbirth. The findings are published online and in the September print edition of the journal Health Affairs.

"Insurance loss and change is common during the perinatal period because changes in employment, income, marital status, and Medicaid eligibility, often go hand-in-hand with pregnancy and childbirth," said Jamie Daw, PhD, assistant professor of Health Policy and Management at Columbia Mailman School, and first author. "We find that Medicaid expansion stabilizes insurance for low-income women, which can improve access to the care women need to support their health and avoid adverse events during pregnancy and postpartum."

Using survey data from the 2012-17 Pregnancy Risk Assessment Monitoring System (PRAMS) the researchers estimated the impact of Affordable Care Act-related state Medicaid expansions on continuity of insurance coverage for low- income women across three time points: preconception, delivery, and postpartum. Low-income women whose household incomes were less than 138 percent of the federal poverty level, the income eligibility threshold for low-income adults under the ACA Medicaid expansion, were included. The sample included 47,617 women, of which 16,363 women resided in 14 nonexpansion states and 31,254 resided in 6 expansion states.

Women in expansion and nonexpansion states had similar levels of insurance stability from preconception to postpartum before Medicaid expansion implementation in 2014 -- 44 percent in expansion states and 41.4 percent in nonexpansion states. However, after 2014, the percent of women moving between being insured and uninsured was reduced by more than a quarter in states that expanded Medicaid, compared to those that did not.

"Insurance disruptions, like maternal morbidity and mortality, particularly affect women who are low-income, are racial and ethnic minorities, and have chronic health conditions," said Lindsay Admon, MD, assistant professor of Obstetrics & Gynecology at the University of Michigan, and senior author. "Perinatal insurance eligibility expansions, such as those examined in this study, may be a powerful strategy for reducing the high rates of maternal morbidity and mortality in the United States."

Daw and colleagues suggest that national rates of perinatal insurance churn would be significantly reduced if all states adopted the ACA-related Medicaid expansion. "With maternal mortality and morbidity rising in the U.S., improvements in the stability of perinatal insurance for low-income women could have important implications for the quality and continuity of perinatal care and, ultimately, maternal and infant health outcomes," said Daw.


Co-authors: Tyler Winkelman, Hennepin Research Institute, Minneapolis, MN; Vanessa Dalton and Katy Kozhimannil, University of Michigan

Columbia University Mailman School of Public Health

Founded in 1922, the Columbia University Mailman School of Public Health pursues an agenda of research, education, and service to address the critical and complex public health issues affecting New Yorkers, the nation and the world. The Columbia Mailman School is the seventh largest recipient of NIH grants among schools of public health. Its nearly 300 multi-disciplinary faculty members work in more than 100 countries around the world, addressing such issues as preventing infectious and chronic diseases, environmental health, maternal and child health, health policy, climate change and health, and public health preparedness. It is a leader in public health education with more than 1,300 graduate students from 55 nations pursuing a variety of master's and doctoral degree programs. The Columbia Mailman School is also home to numerous world-renowned research centers, including ICAP and the Center for Infection and Immunity. For more information, please visit

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