Birth Defects: Risks Women Can Reduce | CDC Findings

Two-Thirds of US Women of Reproductive Age Face Modifiable Birth Defect Risks

A new study reveals that approximately two-thirds of women of reproductive age in the United States have at least one risk factor that could increase the likelihood of serious birth defects, highlighting a critical public health concern. The research, appearing in the American Journal of Preventive Medicine, underscores the importance of addressing these preventable factors, particularly before conception, to improve maternal and infant health outcomes.

Common Birth Defects and Their Impact

Congenital heart defects, orofacial clefts, and neural tube defects (NTDs) are among the most prevalent structural birth defects in the U.S. These conditions, stemming from abnormalities during embryonic development, vary significantly in severity. Current data indicates that approximately 100 out of every 10,000 live births are affected by congenital heart defects, 16 per 10,000 by orofacial clefts, and 7 per 10,000 by NTDs.

Multifactorial Origins and Modifiable Risks

The causes of these birth defects are complex, involving both genetic predispositions and environmental influences. However, researchers have identified several modifiable risk factors – those that can be changed through intervention – including food insecurity, folate insufficiency, vitamin B12 deficiency, pregestational diabetes mellitus, pregestational obesity, and exposure to cigarette smoke. These factors can disrupt the one-carbon cycle metabolism, a crucial series of pathways for cell growth and replication.

NHANES Data Reveals Concerning Trends

The study utilized data from the National Health and Nutrition Examination Survey (NHANES) spanning 2007 to 2020, analyzing trends among over 5,374 non-pregnant, non-lactating women aged 12-49. Researchers found the most significant finding – that two-thirds of women of reproductive age had at least one modifiable risk factor – demonstrates the widespread nature of these preventable issues. “The good news is that they can be lowered,” noted a lead investigator.

Folate Fortification Shows Promise

Public health initiatives, such as the fortification of enriched cereal grains with folic acid since 1992, have demonstrated significant success. The U.S. Public Health Service recommends a daily intake of 400µg of folic acid to prevent NTDs. Researchers observed a notable decrease in women with low blood folate levels during the study period, falling from 23.4% in 2007 to 17.9% in 2020. This improvement is estimated to have prevented over 1,300 NTD cases annually. “Seeing the result of public health efforts in the improved folate status of women of reproductive age underscores both the effectiveness of population-level interventions and the meaningful progress we’ve made in preventing birth defects,” stated a senior official involved in the research.

Key Findings: A Closer Look at Risk Factors

The analysis revealed specific prevalence rates for key modifiable risk factors:

• Low folate status: Approximately one in five women of reproductive age exhibited low red blood cell folate concentrations, and roughly four in five consumed less than the recommended 400µg/day of folic acid for NTD prevention. Around 72% reported not taking folic acid supplements.
• Diabetes: 4.8% of women investigated had diabetes, with 3.5% having uncontrolled or undiagnosed diabetes, indicating inadequate glycemic control.
• Obesity: Nearly one in three women of reproductive age in the U.S. are classified as obese, consistent with previous estimates.
• Tobacco use and exposure: Almost 1 in 5 women of reproductive age showed elevated serum cotinine levels, indicating exposure to tobacco smoke from any source.
• Food insecurity: Approximately 7.3% of women reported very low household food security, with rates decreasing as household income increased. .

Empowering Families and Improving Outcomes

“Every growing family hopes for a healthy pregnancy and healthy baby,” concluded a lead investigator. “Understanding modifiable risk factors for birth defects helps families, healthcare providers, and public health professionals make data-informed decisions that can lead to healthier pregnancies and babies.”

Source: Wang, A., et al. (2025). Trends and Prevalence of Modifiable Risk Factors for Birth Defects Among U.S. Women of Reproductive Age: National Health and Nutrition Examination Survey 2007 to March 2020. American Journal of Preventive Medicine. doi.org/10.1016/j.amepre.2025.107947