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Weight-loss surgery may lower the risk of birth defects

A yawning newborn baby with a hospital ID bracelet.

Nov. 8, 2019 —Women who have weight-loss surgery prior to pregnancy have a lower risk of having babies with birth defects, according to a new study. That may help alleviate some long-standing concerns about whether weight-loss surgery could increase the risk for major birth defects.

Why the worry?

Because weight-loss surgery limits the amount a food a person can take in, it can raise the risk for nutritional deficiencies. That includes nutrients like iron and folate, which are vital to a baby's development.

The researchers looked at data from more than 33,000 births in Sweden between 2007 and 2014 and compared two groups of women. The first group had already had weight-loss surgery and lost an average of about 88 pounds before their first prenatal checkup. The second group hadn't had surgery and were similar to the pre-surgery weights of the first group.

The study found that the risk of major birth defects was about 30% lower in children of the surgery group. In fact, their risk of birth defects was almost identical to children of moms who start pregnancy at a healthy weight.

Behind the science

Women in the weight-loss surgery group had also reduced their need for diabetes medicine before pregnancy. Researchers suggested that could be part of the reason for the lower risk of major birth defects. Uncontrolled diabetes increases the risk of birth defects.

Still, they said it was vital to closely monitor these women during pregnancy. That includes additional ultrasounds to keep an eye on fetal growth, as well as nutritional counseling. And they recommended checking for nutritional deficiencies, including:

  • Iron.
  • Folic acid.
  • Calcium.
  • Vitamin B12.

The study was published in JAMA.

To learn more about giving your baby a healthy start, visit our Pregnancy health topic center.

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