August 26, 2025
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A new study found that 66% of women of childbearing age had modifiable risk factors for birth defects that could be addressed through lifestyle or policy interventions.
Two of three women of childbearing age in the United States are at heightened risk for birth defects due to at least one environmental or lifestyle factor — but these factors are modifiable, new research shows.
These factors include food insecurity, obesity, smoking exposure, untreated diabetes and low folate levels, and they're associated with pre-eclampsia, stillbirth, premature birth and abnormal brain development, according to the study, published Tuesday.
"We can't underscore enough how important it is to raise awareness about these risk factors and encourage women to speak with their doctors if they have any concerns or questions before becoming pregnant," Arick Wang, the lead author of the study, told NBC News.
About 1 in every 33 babies born in the U.S. has birth defects, which are health conditions that develop in utero, usually within the first three months of pregnancy. Babies born with birth defects, which can impact every part of the body, including the brain and heart, often need medical interventions. Birth defects are also the leading cause of infant mortality, accounting for 1 in 5 infant deaths, according to the Centers for Disease Control and Prevention.
"Understanding modifiable risk factors for birth defects helps families, health care providers, and public health professionals make data-informed decisions that can lead to healthier pregnancies and babies," Wang said in a news release.
The study used data from about 5,400 women who participated in the CDC's National Health and Nutrition Examination Survey between 2007 and 2020. Findings from the survey – which started in 1960 and is ongoing – are used to develop national estimates for chronic diseases and determine how diseases and behaviors increase the risk of adverse health outcomes, including death. The series of surveys also helps guide public health policy.
The new study found:
• About 72% of women do not get the recommended daily amount of folic acid, a vitamin B that is needed to prevent neural tube defects.
• Nearly 5% of women had diabetes, about 4% of which was undiagnosed or unmanaged.
• Nearly 1 in 3 women had obesity.
• Nearly 1 in 5 women had blood results showing they used or were regularly exposed to tobacco smoke.
One positive finding was that the number of women with low blood folate levels dropped during the study period, from 23% to 18%.
Folate, vitamin B9 found in leafy greens, dairy products, nuts and other foods, is necessary for the body to make new red blood cells and DNA, according to the Cleveland Clinic.
