Most Women Know Folic Acid Prevents Birth Defects, Yet Few Take It Correctly, Study Finds

Almost every woman surveyed in a large new study of reproductive-age women in China knew that folic acid helps prevent neural tube defects, yet fewer than one in three who became pregnant or planned a pregnancy followed the complete supplementation regimen that makes the vitamin truly protective. The findings, published in BMC Public Health by a research team led by investigators at Peking University’s School of Nursing, expose a striking gap between what women know in general terms and what they actually do during the critical weeks when a baby’s neural tube forms. The study suggests that the battle against these devastating birth defects is not being lost in awareness campaigns, but in the fine print of when to start, how much to take, and how long to continue.

Neural tube defects, which include spina bifida and anencephaly, arise when the embryonic structure that becomes the brain and spinal cord fails to close properly during the first four weeks of development, often before a woman even realizes she is pregnant. Decades of evidence have established that adequate folic acid intake around the time of conception can prevent a large proportion of these defects, which remain a major preventable cause of congenital disability worldwide. Because the window for protection closes so early, public health authorities recommend that women begin taking a daily folic acid supplement before conception and continue through at least the first trimester. The new research set out to determine whether women of childbearing age in mainland China are translating that general message into precise, correctly timed behavior.

The investigation took a mixed-methods approach conducted between June and September 2024. In the quantitative phase, the researchers administered a study-specific questionnaire online to 5,741 women aged 18 to 49 years recruited from different regions of mainland China through a convenience sample. The survey assessed folic acid-related knowledge and supplementation behaviors, and the team used univariable and multivariable logistic regression analyses to examine the association between knowledge scores and correct supplementation. In the qualitative phase, the researchers conducted semi-structured interviews with 18 pregnant women, guided by the Health Belief Model, a well-established psychological framework that explains health behavior through perceptions of susceptibility, severity, benefits, obstacles, and cues to action. Qualitative data were analyzed using directed content analysis, and the quantitative and qualitative findings were integrated through a joint display to reveal where numbers and lived experience converged or diverged.

The headline numbers from the survey reveal a knowledge pyramid that narrows sharply as it descends from general awareness to actionable detail. Among the 5,741 survey participants, 5,490 women, or 95.6 percent, knew that folic acid prevents neural tube defects. But only 3,594, or 62.6 percent, knew the correct timing for supplementation, and just 2,949, or 51.4 percent, knew the recommended daily dose. In other words, while nearly all women had absorbed the core public health message, roughly half were missing the operational specifics that determine whether supplementation actually protects an embryo during the window of neural tube closure.

Behavioral data told an even more sobering story. Among the 4,470 women with pregnancy or pregnancy-planning experience, 3,858, or 86.3 percent, had obtained folic acid, and 3,708, or 83.0 percent, had actually taken it. Yet only 1,281 women, or 28.7 percent, adhered to the full regimen. The steep drop-off between obtaining the supplement and completing the recommended course indicates that the challenge is not access or initial motivation but sustained, correctly timed adherence. A bottle of folic acid purchased after a positive pregnancy test, or abandoned partway through the preconception period, offers far less protection than one taken daily from before conception onward.

The statistical analysis confirmed that knowledge is not merely correlated with good practice by chance. After adjusting for other variables, the researchers found that knowledge scores were significantly associated with adherence to correct supplementation, with an adjusted odds ratio of 1.493 and a 95 percent confidence interval of 1.43 to 1.56. Each increment in knowledge corresponded to meaningfully higher odds of taking folic acid correctly. This dose-response-like relationship between understanding and behavior strengthens the case that the knowledge gaps in timing and dosage are not benign oversights but active contributors to suboptimal supplementation practices.

The qualitative interviews added psychological texture to these statistics. Using the Health Belief Model as an analytical lens, the researchers identified barriers spanning all five of the framework’s core constructs. Women’s decisions were shaped by how susceptible they perceived themselves to be to having an affected pregnancy, how severe they believed the consequences would be, how beneficial they judged supplementation to be, what obstacles they encountered in obtaining and taking the supplement, and what cues prompted them to act. These perceived factors help explain why a woman who knows that folic acid prevents birth defects in the abstract might still fail to start early, take the right dose, or persist through the recommended duration.

When the quantitative and qualitative strands were integrated through the joint display, a coherent picture of the knowledge-practice gap emerged. The researchers concluded that limited knowledge of the recommended timing and dosage, health information that was insufficiently individualized, and brief counseling from healthcare providers may all contribute to suboptimal supplementation practices. Generic advice delivered in passing during a busy prenatal visit appears inadequate to convey the operational precision that folic acid prevention demands. Women need to hear not just that the vitamin matters, but exactly when to begin, how much to take each day, and how long to continue, with that guidance tailored to their circumstances.

The study, which received no external funding and was approved by the Institutional Review Board of the Peking University Biomedical Ethics Committee, carries clear implications for preconception health education in China and beyond. The authors call for preconception health education that provides specific, individualized, and theory-informed guidance on when, how much, and how long folic acid should be taken. Grounding educational interventions in behavioral frameworks such as the Health Belief Model could help address the perceived barriers that interviews uncovered, while longer and more structured provider counseling could close the timing and dosage knowledge gaps that the survey documented.

For a preventable cause of congenital disability, the distance between 95.6 percent awareness and 28.7 percent full adherence represents an enormous unrealized opportunity. The neural tube closes within the first four weeks of embryonic development, meaning that every month of delayed initiation or interrupted adherence translates into real risk. This research demonstrates that closing the gap requires moving beyond slogans about folic acid’s importance and toward communication that equips women with the concrete, actionable details of the regimen. As the authors’ findings make plain, knowing that a supplement prevents birth defects is only the first step; knowing precisely how to take it is what turns knowledge into protection.

Subject of Research: Folic acid supplementation knowledge and adherence for neural tube defect prevention among women of childbearing age in China

Article Title: Discrepancy between knowledge and practice in folic acid supplementation for NTD prevention: a mixed-methods study of Chinese women

Article References: Li, J., Peng, X., He, H., Liu, N., Dong, W., Lv, D., Li, S., & Zhu, X. (2026). Discrepancy between knowledge and practice in folic acid supplementation for NTD prevention: a mixed-methods study of Chinese women. BMC Public Health. https://doi.org/10.1186/s12889-026-29848-y

Image Credits: AI Generated

DOI: 10.1186/s12889-026-29848-y

Keywords: folic acid, neural tube defects, women of childbearing age, medication adherence, health belief model, mixed-methods research, preconception health, public health, China, nutritional supplements, health education, pregnancy planning