Women without health insurance are far less likely to take folic acid supplement

By Dr. Liji Thomas, MDReviewed by Lauren HardakerJun 10 2026

A study of more than 85,000 U.S. women found that insurance coverage, pregnancy status, and education were more closely linked to folic acid supplement use than birthplace, highlighting healthcare access as a potential target for reducing disparities in neural tube defect prevention.

Study: Advancing Understanding of Racial and Ethnic Disparities in Folic Acid Supplementation via National Institutes of Health All of Us Data. Image credit: Davor Geber/Shutterstock.com

A recent study published in the journal Sexual & Reproductive Healthcare suggests that healthcare access, particularly insurance coverage, was strongly associated with racial, ethnic, and social disparities in folic acid supplementation among women of reproductive age using data from the National Institutes of Health's All of Us Research Program.

Preventable birth defects still affect thousands

Folic acid supplementation before and during early pregnancy helps prevent neural tube defects (NTDs), congenital defects that include spina bifida and anencephaly. Currently, these affect about 3,000 pregnancies in the US each year, putting these among the top birth defects in this country. Worldwide, 0.2% of births are complicated by NTDs.

This is unfortunate as NTDs are among the most preventable of birth defects, via folic acid supplementation. Because neural tube closure occurs very early in embryonic life, often before pregnancy is recognized, public health guidelines recommend that all women who may become pregnant consume folic acid regularly. Despite these recommendations, only 20%-40% of women who recently conceived or planned to become pregnant were taking folic acid. This percentage is still lower among women with unplanned pregnancies.

Population-level nutritional and health surveys and pregnancy risk assessment studies continue to show marked variations in folic acid supplementation levels across ethnic and racial groups. This led to fortification of cereals and grain products to prevent NTDs, but gaps still persist between Hispanic or Black women and White women.

This could, in part, reflect food biases between groups and the fact that foods like corn masa, which are more commonly consumed by Hispanic communities, are less likely to be fortified. The study also notes that voluntary fortification of corn masa flour has not substantially improved red blood cell folate concentrations among Hispanic women, prompting calls for broader mandatory fortification measures.

However, mandatory fortification of staple foods could still leave disparities for multiple reasons, such as inconsistent intake of fortified foods across groups and the observed plateau after an initial drop in NTD prevalence (rather than a continued decline) even with mandatory fortification.

In addition, Hispanic women in the USA are less knowledgeable about the importance of folic acid in early pregnancy, less health-literate, and report language barriers to understanding health messaging. Healthcare access and insurance coverage have previously been reported to improve folic acid intake, as has healthcare education before conception.

The current study investigated the role of race, ethnicity, nativity, and social determinants of health (SDOH), including income, education, insurance status, and pregnancy, on folic acid supplementation among Hispanic, non-Hispanic Black, and non-Hispanic White women of reproductive age.

Researchers analyzed data from 85,874 women aged 18–49 years enrolled in the NIH All of Us Research Program between 2018 and 2022. This study includes communities historically underrepresented in biomedical research. The cohort included both pregnant and non-pregnant women.

Supplement use varied across racial groups

The average age was highest among Hispanic women born outside the US at 43 years, followed by Black women at 42 years and White women at 41 years. US-born Hispanic women were younger on average, with a mean age of 38 years. Foreign-born Hispanic women were also the most likely to be pregnant.

White women had the highest levels of education and income, with one-third holding a college degree. In contrast, Black women were most likely to fall into the lowest income category.

Health insurance coverage also varied substantially across groups. Nearly 96% of White women were insured, compared with 91% of US-born Hispanic women and 85% of Black women. Coverage was lowest among foreign-born Hispanic women, at 74%.

The rates of folic acid supplementation recorded in the electronic health record dataset were very low across all groups, which the authors note may partly reflect incomplete capture of supplement use in medical records.

After adjusting for demographic and socioeconomic factors, each additional year of age was associated with a 4% increase in the odds of folic acid supplementation. Women in middle-income categories were less likely to take supplements, while those with some college education had 18% higher odds of supplementation than women with advanced degrees, the reference group used in the analysis.

One of the study's more unexpected findings was that Black women had more than twice the odds of folic acid supplementation compared with White women. This contrasts with previous research. The authors suggest that higher rates of anemia, including sickle cell disease, may lead to more frequent healthcare interactions and greater exposure to folic acid recommendations, although this explanation was not directly examined in the study.

Pregnancy was another strong predictor of supplementation, more than doubling the odds of folic acid use. In contrast, women without health insurance were 56% less likely to take folic acid supplements. The authors suggest that reduced access to healthcare may limit opportunities for preventive counseling and recommendations about prenatal supplementation.

Hispanic-only analysis

When only Hispanic women were included in the analysis, older age, pregnancy, and having some college education were associated with significantly higher odds of supplementation. As with the overall analysis, the lack of insurance coverage reduced the odds of supplementation by 76%. However, there was no change in risk with the nativity status.

Strengths and limitations

A major strength of the study is its use of a large and diverse dataset, including those often underrepresented in past research. This allowed examination of differences across different Hispanic subgroups. Moreover, they had access to self-reported and medical record data, increasing the data's comprehensiveness. They also explored multiple SDOH simultaneously, helping to understand potential interactions in influencing folic acid supplementation.

However, the study was observational and cannot establish causation. Folic acid use was assessed from medical records rather than direct measurements of serum or red blood cell folate status, and supplement use may have been underreported if it was not captured in medical records.

The All of Us study has been shown to overrepresent older, educated, insured women, and the current sample had a very low rate of Spanish-language surveys, suggesting that Hispanics who primarily speak Spanish might have been underrepresented.

Future studies should focus on the mechanisms underlying these disparities, identify barriers to folic acid use, and link supplement use to actual folate biomarkers and pregnancy outcomes to improve the clinical relevance of the findings.

Healthcare access emerges as the strongest predictor of folic acid use 

The study suggests that the main factors affecting folic acid supplementation across all groups include pregnancy status, education, and insurance coverage. Older age and pregnancy were associated with greater supplement use, while lack of insurance reduced the likelihood of supplementation. Compared to birthplace, healthcare access exerted greater influence on the outcome.

The authors suggest that bridging insurance gaps and increasing access to preventive health services, including counseling, could improve folic acid supplementation rates and help reduce disparities associated with NTD risk.

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