News Release

ACA Medicaid expansion significantly improves insurance coverage for pregnant people: Implications for the Build Back Better Act

Peer-Reviewed Publication

Columbia University's Mailman School of Public Health

January 4, 2022-- The Affordable Care Act Medicaid expansion increased preconception and postpartum Medicaid coverage and led to significant declines in uninsurance and insurance churn, according to a study conducted at Columbia University Mailman School of Public Health. There was limited evidence, however, that Medicaid expansion increased perinatal health care use or improved infant birth outcomes overall. The findings are published in the January 2022 issue of the journal Health Affairs.

“In earlier research before the Affordable Care Act (ACA), we found high rates of uninsurance among reproductive-aged women” said Jamie Daw, PhD, Columbia Mailman School assistant professor of health policy and management, and senior author. “In addition, insurance churn—moving between insurance and uninsurance or switching insurers—was common around pregnancy, and high rates of coverage instability may have contributed to lower access to care and poorer maternal and child health outcomes. This disproportionately impacted low-income people and members of racial and ethnic minority groups who qualify for pregnancy Medicaid coverage.”

Drawing on original, peer-reviewed quantitative research studies, Daw and colleagues systematically analyzed data published between January 2014 and April 2021. They examined the effect of the ACA state Medicaid expansions on insurance coverage, health care use, and health outcomes measured between one month prior to conception through one year postpartum, and neonatal outcomes within twenty-seven days of birth. The researchers identified 35 unique studies that met their screening criteria.

Increases in Medicaid coverage were greater during the preconception and postpartum periods than at delivery, since pregnant people already qualified for Medicaid from conception to sixty days after birth before the ACA.

“Despite large coverage increases before and after pregnancy, we found limited evidence that the ACA Medicaid expansion improved overall perinatal health care use or health outcomes in the first few years after implementation,” noted Meghan Bellerose, MPH, current PhD student at Brown University School of Public Health, graduate of Columbia Mailman School, Department of Population and Family Health, and first author. “However, one study found that the ACA Medicaid expansion was associated with reduced racial disparities in birth outcomes such as preterm birth, and another found a reduction in overall maternal mortality. These results are promising and merit further exploration as the U.S. continues to pursue strategies to reduce racial disparities in maternal mortality and morbidity.”

“Our findings indicate that Medicaid expansion to low-income adults is a very effective approach to increase preconception and postpartum health insurance coverage,” said Daw. “Our ability to observe corresponding changes in health care use and outcomes is partly related to a lack of data collection on preconception and postpartum outcomes in the U.S.  Our results are highly relevant to the recent maternal healthcare call to action from the White House  and the postpartum Medicaid provisions within the Build Back Better Act, suggesting that these provisions will result in large coverage gains, but more data will be needed for rigorous evaluation of the impact of Medicaid policy changes on maternal health disparities.”

A co-author is Lauren Collin of Columbia Mailman School.

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 fourth 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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