Ann Arbor, August 26, 2025 – A groundbreaking new analysis leveraging data from the renowned National Health and Nutrition Examination Survey (NHANES) has illuminated a critical public health concern affecting millions of women across the United States. The comprehensive study, involving 5,374 women of reproductive age, reveals that an alarming two-thirds possess at least one modifiable risk factor that significantly elevates the likelihood of serious birth defects. These risk factors, modifiable through lifestyle or healthcare interventions, include low folate status, uncontrolled diabetes, obesity, tobacco exposure, and food insecurity. The findings, published in the prestigious American Journal of Preventive Medicine, underscore the urgency with which healthcare systems, policymakers, and public health programs must prioritize early intervention strategies before pregnancy to mitigate the risk of congenital anomalies.
Birth defects such as congenital heart malformations, orofacial clefts, and neural tube defects (NTDs) represent a spectrum of structural abnormalities arising due to disruptions during embryonic development. These defects range widely in severity and prevalence, with congenital heart defects being the most frequent, affecting approximately 100 per 10,000 live births in the U.S. Orofacial clefts and NTDs, while less common, still pose significant clinical challenges and long-term health consequences. A key insight from this study is the elucidation of how environmental and lifestyle factors interface with biological processes to influence embryogenesis, especially through pathways like the one-carbon metabolism cycle, which is essential for DNA synthesis and cellular replication.
Dr. Arick Wang, the primary investigator affiliated with the CDC’s Division of Birth Defects and Infant Disorders, emphasizes the complex interplay of genetic, environmental, and nutritional factors contributing to these birth defects. He highlights that while some risk elements are immutable, a substantial portion involve modifiable behaviors or conditions. These include inadequate intake of key micronutrients such as folate and vitamin B12, pre-existing metabolic disorders like diabetes and obesity, and exposure to tobacco smoke, whether active or passive. Each factor exerts influence through mechanisms disrupting cellular metabolism, epigenetic regulation, and oxidative stress pathways during early fetal development.
This pivotal study exploited NHANES data from 2007 to 2020, meticulously analyzing trends and prevalence patterns of these modifiable risk factors in a nationally representative cohort of U.S. women aged 12 to 49 who were neither pregnant nor lactating. The longitudinal nature of the dataset allowed researchers to observe not only persistence but also changes over time in nutritional status, chronic disease prevalence, and behavioral exposures. The analytical approach incorporated advanced statistical modeling to adjust for sociodemographic variables and isolate the independent effects of each risk factor, providing granular insights into public health dynamics.
Among the most noteworthy findings, the investigators documented a meaningful decline in the proportion of women with low red blood cell folate concentrations, dropping from 23.4% to 17.9% over the study period. This trend correlates with national folic acid fortification policies implemented over past decades, designed to reduce the incidence of neural tube defects. The data suggest that these interventions have prevented over 1,300 cases of NTDs annually, validating the efficacy of public health nutrition strategies at a population level. However, despite this progress, roughly 80% of women still fall short of the recommended daily intake of 400 micrograms of folic acid, underscoring ongoing gaps in supplement adherence and dietary sufficiency.
Diabetes, particularly pregestational diabetes mellitus, was noted in nearly 5% of the studied demographic, with a concerning subset exhibiting poor glycemic control or undiagnosed conditions. Given the teratogenic risks associated with hyperglycemia during early gestation, these findings point to the critical need for improved screening, patient education, and metabolic management prior to conception. Similarly, obesity prevalence mirrored national trends, with approximately one-third of reproductive-age women classified as obese based on body mass index criteria, reflecting an entrenched public health epidemic with known implications for adverse pregnancy outcomes including birth defects.
Tobacco exposure in its various forms—active smoking, vaping, or passive inhalation—remained prevalent in nearly 20% of the surveyed women, as indicated by elevated serum cotinine measurements. This is particularly alarming given the established links between cotinine-related oxidative damage and impaired fetal development. The study also drew attention to socioeconomic disparities, with about 7.3% of participants experiencing very low household food security. Food insecurity, a marker for nutritional inadequacy and chronic stress, was inversely related to household income, revealing systemic inequities that exacerbate risk profiles for vulnerable populations.
These results collectively challenge the paradigm that birth defects are an inevitable consequence of genetics alone. Instead, they establish a strong epidemiological foundation for precision public health initiatives targeting modifiable risk exposures well before pregnancy begins. Dr. Wang and colleagues advocate for integrated interventions encompassing nutritional counseling, chronic disease management, smoking cessation programs, and socioeconomic support frameworks to create resilient maternal health environments. The ability to alter these risk factors represents a significant opportunity to improve pregnancy outcomes and reduce the societal burden of birth defects.
Furthermore, the study’s methodological rigor—employing robust data synthesis and longitudinal tracking—offers a replicable model for future surveillance efforts aiming to capture dynamic health trends within reproductive cohorts. The data also provide a compelling argument for expanding preconception care paradigms beyond traditional obstetric settings to encompass community health, policy reform, and cross-sector collaboration. By embedding modifiable risk factor assessments into routine women’s health protocols, clinicians can identify at-risk individuals, tailor interventions, and foster healthier pregnancies.
While the scope of this analysis was deliberately limited to well-established modifiable risk factors, it opens avenues for broader research exploring emerging determinants such as environmental toxins, psychosocial stressors, and epigenetic modifications. The integration of biomarker analysis with behavioral data marks a significant advancement in understanding the biological underpinnings of birth defects, laying the groundwork for nuanced prevention strategies that consider both biology and social context.
In conclusion, this landmark research spotlights the pervasive nature of modifiable risk factors among U.S. women of reproductive age and highlights both progress made and persistent challenges. The evidence strongly supports intensified public health efforts to promote folate sufficiency, control metabolic conditions, reduce tobacco exposure, and alleviate food insecurity. These measures hold promise not only for mitigating birth defect risk but also for enhancing overall maternal and child health outcomes. As Dr. Wang succinctly states, “Understanding these modifiable factors empowers families, healthcare providers, and public health officials to make informed choices that pave the way for healthier generations.”
Subject of Research: People
Article Title: Trends and prevalences of modifiable risk factors for birth defects among U.S. women of reproductive age: NHANES 2007-March 2020
News Publication Date: 26-Aug-2025
Web References:
https://www.ajpmonline.org/
http://dx.doi.org/10.1016/j.amepre.2025.107947
References:
Wang, A. et al. (2025). Trends and prevalences of modifiable risk factors for birth defects among U.S. women of reproductive age: NHANES 2007-March 2020. American Journal of Preventive Medicine. https://doi.org/10.1016/j.amepre.2025.107947
Keywords: birth defects, modifiable risk factors, folate deficiency, diabetes, obesity, tobacco exposure, food insecurity, neural tube defects, congenital heart defects, orofacial clefts, NHANES, women’s health, preconception care
