Children born to mothers who had COVID-19 during pregnancy may be more likely to develop obesity, according to a new study published in the Journal of Clinical Endocrinology & Metabolism.

More than 100 million COVID-19 cases have been reported in the US since 2019, and there is limited information on the long-term health effects of the infection. Pregnant women make up 9% of reproductive-aged women with COVID-19, and millions of babies will be exposed to maternal infection during fetal development over the next five years, according to a press release by the Endocrine Society.

“Our findings suggest that children exposed in utero to maternal COVID-19 have an altered growth pattern in early life that may increase their risk of obesity, diabetes, and cardiovascular disease over time,” says Lindsay T. Fourman, MD, of Massachusetts General Hospital, in a press release. “There is still a lot of research needed to understand the effects of COVID-19 on pregnant women and their children.”

The researchers studied approximately 150 infants born to mothers who had COVID-19 during pregnancy and found they had lower birth weight followed by greater weight gain in the first year of life as compared to approximately 130 babies whose mothers did not have prenatal infection. These changes have been associated with an increased risk for obesity, diabetes, and cardiovascular disease in childhood and beyond.

“Our findings emphasize the importance of long-term follow-up of children exposed in utero to maternal COVID-19 infection, as well as widespread implementation of COVID-19 prevention strategies among pregnant individuals,” says Andrea G. Edlow, MD, of Massachusetts General Hospital, in a press release. “Larger studies with longer follow-up duration are needed to confirm these associations.”

The study received funding from the National Heart, Lung, and Blood Institute, the National Institute of Diabetes and Digestive and Kidney Diseases, the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the Nutrition Obesity Research Center at Harvard, the Boston Area Diabetes Endocrinology Research Center, the National Institute of Allergy and Infectious Diseases, the American Heart Association, and the Simons Foundation.