Irvine, Calif., June 8, 2026 — Access to healthcare and insurance coverage strongly influence whether women take recommended amounts of folic acid to help prevent serious birth defects, according to University of California, Irvine researchers using the National Institutes of Health's All of Us Research Program data.
The study, published in the Journal of Sexual and Reproductive Healthcare , analyzed health data from more than 85,000 women ages 18 to 49 across the U.S. Researchers examined how race, ethnicity, insurance coverage, income and other social factors affect folic acid consumption.
The project brought together researchers across multiple UC Irvine disciplines, including the School of Pharmacy & Pharmaceutical Sciences, the Department of Chicano/Latino Studies and the Department of Psychology, highlighting the value of cross-divisional collaboration in addressing public health disparities.
Folic acid, a form of vitamin B, helps prevent neural tube defects such as spina bifida and anencephaly, which develop early in pregnancy, often before a woman knows she is pregnant. National guidelines recommend daily folic acid for women who could become pregnant, but researchers found overall use remains low.
Women without health insurance were significantly less likely to report taking folic acid supplements, according to the study. Older pregnant women, in particular, were more likely to use supplements, which researchers said may reflect greater access to healthcare providers and prenatal care.
The study also examined racial and ethnic differences in supplement use. Non-Hispanic Black women were more likely than non-Hispanic White women to report taking folic acid supplements. Among Hispanic participants, researchers found no significant difference between U.S.-born and foreign-born women. Instead, age, being pregnant, educational attainment and health insurance coverage were associated with supplementation within this group.
The findings suggest that structural barriers, particularly healthcare access, may play a larger role in folic acid use than birthplace alone.
"Preventing neural tube defects begins long before pregnancy, which is why access to healthcare and preventive education is so important for all women of reproductive age," said corresponding author Yael Marks, health sciences assistant clinical professor in the School of Pharmacy & Pharmaceutical Sciences. "Our findings show that structural barriers like insurance coverage can strongly influence whether women receive this simple but lifesaving intervention."
Co-author Isabel Almeida with the Department of Chicano/Latino Studies and Department of Psychology said the research's interdisciplinary emphasis provided a broader understanding of how social and cultural factors influence preventive healthcare access.
"This collaboration allowed us to examine folic acid supplementation not only as a medical issue, but also through the lens of social inequities and healthcare access," Almeida said. "Bringing together researchers from different disciplines helps us better understand the barriers communities face and identify more effective public health solutions."
Researchers said the findings can help inform public health efforts to reduce preventable birth defects through improved healthcare access, education and culturally responsive outreach.
The findings come as a growing number of states consider policies to increase folic acid fortification in corn masa flour. In January 2026, California became the first state to require folic acid fortification of corn masa flour products, including tortillas, to help reduce neural tube defects among populations that consume masa-based foods as dietary staples.
The study also supports efforts elsewhere to expand folic acid fortification in corn masa flour and tortillas, foods commonly consumed in many Hispanic households.
The All of Us Research Program, funded by the National Institutes of Health, is one of the nation's largest health research initiatives and aims to enroll at least 1 million participants from diverse backgrounds to advance personalized medicine and public health research.
UC Irvine is a host site for the All of Us Research Program and includes collaborations across the School of Medicine, the Genetic Epidemiology Research Institute and other campus partners.
Additional authors include Brian Vu and Tara Mostafazadeh of the Department of Clinical Pharmacy Practice at UC Irvine.
About the University of California, Irvine: Founded in 1965, UC Irvine is a member of the prestigious Association of American Universities and is ranked among the nation's top 10 public universities by U.S. News & World Report. The campus has produced five Nobel laureates and is known for its academic achievement, premier research, innovation and anteater mascot. Led by Chancellor Howard Gillman, UC Irvine has more than 36,000 students and offers 224 degree programs. It's located in one of the world's safest and most economically vibrant communities and is Orange County's second-largest employer, contributing $7 billion annually to the local economy and $8 billion statewide. For more on UC Irvine, visit www.uci.edu .
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