Children born to mothers who have high levels of lead in their blood have a higher likelihood of being overweight and obese, compared to children whose mothers have low levels of lead in their blood. However, the study’s authors believe that adequate folate may help reduce that risk in children whose mothers have high lead levels.

That’s according to a recent study conducted by Xiaobin Wang, M.D., of the Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland.

Researchers began by looking at data from the Boston Birth Cohort, a large observational study that aims to determine the causes of preterm birth. They analyzed blood samples from 1,442 mothers for lead exposure 24 to 72 hours after they gave birth. They then periodically measured the weight of a child from each mother throughout childhood.

At an average age of 1.8 years old, children born to mothers with high lead levels were more than four times as likely to be overweight or obese than children born to mothers with low lead levels.

Early in the study, participating women answered a questionnaire where they indicated whether they had taken a supplement containing folic acid in the second and third trimesters of pregnancy. Researchers found that the child’s risk of being overweight or obese decreased in the women with high lead levels, if the mother had adequate levels of folate 24 to 72 hours after giving birth.

Study authors note that if their results are confirmed, offering folic acid to women who test positive for high levels of lead exposure could potentially reduce their children’s risk of being overweight or obese.

The U.S. Preventive Services Task Force recommends that anyone who is planning to or could become pregnant take a daily supplement with 400 to 800 micrograms of folic acid (the synthetic form of folate), starting at least one month before pregnancy and continuing through the first two to three months, to help prevent neural tube defects.

The study was funded by the National Institutes of Health and Health Resources and Services Administration and appears in JAMA Network Open.

Keep this in perspective

This was an observational study, which means it found a link but cannot prove that folate caused the lower risk. The researchers noted their results would need to be confirmed.

Protecting your family from lead

Lead exposure during pregnancy and breastfeeding can cause lasting health effects, and CDC guidelines do not identify any safe level of lead exposure for a mother or her baby. If you’re pregnant, talk with your health care provider about possible sources of lead in your home, work, or hobbies, and whether a blood lead test makes sense for you.

Updated October 2026. This article is for general information and is not a substitute for advice from your health care provider.

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