Modifiable Risk Factors for Birth Defects Rising Among Women, Suggests Study
USA: Researchers have found in a new analysis of over a decade of NHANES data that two-thirds of U.S. women of reproductive age have at least one modifiable risk factor for birth defects, such as obesity, low folate levels, or smoking exposure. About 10% had three or more risk factors, with trends showing an overall increase in such risks over time.
The study, published in the American Journal of Preventive Medicine, analyzed data from the National Health and Nutrition Examination Survey (NHANES) collected between 2007 and March 2020. Investigators evaluated modifiable factors linked to common birth defects, including congenital heart defects, neural tube defects, and orofacial clefts, among nonpregnant women aged 12–49 years. The assessment included measures such as body mass index, food security, folic acid supplement use, smoking exposure, diabetes status, and concentrations of red blood cell folate and vitamin B12.
The study revealed the following findings:
- The analysis included 5,374 women, and 66.4% had at least one modifiable risk factor.
- Obesity affected 33.8% of participants.
- Low folate status was observed in 19.5% of women, falling below the recommended threshold for neural tube defect prevention.
- Smoking exposure was reported by 18.8% of women.
- Diabetes was present in 4.8% of women.
- Very low food security affected 6.7% of participants.
- The proportion of women with at least one risk factor increased from 65.3% in 2007–2010 to 69.5% by 2020.
- Diabetes rates nearly doubled during the study period, highlighting the need for early detection and management.
The study highlights critical gaps in preconception health, particularly the low use of folic acid supplements and insufficient intake to meet the recommended 400 µg/day for neural tube defect prevention. While most women achieved folate levels adequate for prevention—likely due to food fortification programs—there remains room for improvement. Experts emphasize that these findings reinforce the need for targeted public health interventions, such as promoting healthy weight management, increasing awareness of folate supplementation, reducing smoking exposure, and enhancing diabetes screening before pregnancy. Such measures could help lower the prevalence of birth defects and improve maternal and infant outcomes.
The analysis benefits from NHANES’ nationally representative sample and use of biomarker data rather than self-reports. However, limitations include reliance on single-time-point measurements for conditions like diabetes, declining participation rates over time, and exclusion of certain episodic or medication-related risk factors.
With approximately two in three women of reproductive age carrying modifiable risk factors for birth defects, the study highlights the urgency of preventive strategies. Regular screening, nutrition education, and lifestyle interventions before conception could significantly reduce adverse birth outcomes and enhance the health of future generations.
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