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New research shows how reversible risks, especially preconception, can be identified and addressed to support healthy pregnancies, and improve birth outcomes and public health programs.
The analysis is based on data from the National Health and Nutrition Examination Survey (NHANES) suggests two thirds of reproductive-aged women in the US have at least 1 modifiable risk factor that can increase the chance of serious birth defects.
“The most significant finding—that two thirds of women of reproductive age had at least one modifiable risk factor—highlights how common these changeable risk factors are,” says the study’s leading investigator, Dr Arick Wang from the National Centre on Birth Defects and Developmental Disabilities.
“The good news is that they can be lowered.”
The survey was completed by 5,374 women between the ages of 12 and 49 in the United States. The researchers focused on risk factors like food insecurity, vitamin B12 deficiency, Body Mass Index (BMI), pregestational diabetes and exposure to cigarette smoke.
The study was limited to selected birth defects such as congenital heart defects, which are structural heart problems present at birth, and orofacial clefts where a baby’s lip or palate does not form completely.
“The pathogenesis of these common birth defects is multifactorial and includes both nonmodifiable and modifiable risk factors,” says Wang.
“These risk factors may contribute to birth defects through the one-carbon cycle metabolism, a series of pathways essential for cell growth and replication.”
The study also investigated neural tube defects (NTD). While low blood folate can increase the risk of NTD, previous studies have found that these risks can be lowered by taking folic acid before and during early pregnancy.
Since 1992, the US Public Health Service has recommended taking 400µg a day of folic acid during pregnancy to prevent NTD. The results demonstrate the importance of public health measures like this and how they can help promote healthy pregnancy and babies
“I was pleased to see a meaningful decrease of women with low blood folate status over the course of this study period,” says Wang.
“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.”
In 2007, the study found that 23.4% of women had low blood folate status. By 2020, the researchers revealed this figure had dropped to 17.9%.
The data used from the NHANES is a cross-sectional representative sample of US citizens. To complete the survey, participants had household interviews, 2 dietary intake recall interviews and an in-person health examination.
The researchers found that 4.8% of women of reproductive age had diabetes and 1 in 3 women had obesity.
The study shows nearly 1 in 5 women had elevated serum cotinine levels which can indicate tobacco exposure from smoking, vaping or second-hand exposure.
All these risk factors can potentially have adverse effects on both mothers and their babies. Babies whose mothers smoked while pregnant, for example, are at a higher risk of developing weaker lungs and low birth weights, which may increase the risk of sudden unexpected death in infancy (SUDI).
However, the promising news is that with help and support from public health campaigns, health care providers and families, these risk factors can often be mitigated and lowered.
“Every growing family hopes for a healthy pregnancy and healthy baby,” says Wang. “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.”
The research has been published in the American Journal of Preventive Medicine.