The consequences of COVID-19 during pregnancy are still unfolding, but a new study delivers sobering news: Prenatal exposure to the virus may be linked to childhood obesity.
Looking at nearly 280 infants, researchers found those whose mothers had COVID while pregnant had lower birth weight compared to babies whose moms did not have a COVID infection. That was followed by greater weight gain in the first year of life.
Together these changes could increase risk for obesity, diabetes and cardiovascular disease in childhood and later, the study authors said.
Pregnant women have made up 9% of reproductive-aged women with COVID so far. Millions of babies will be exposed to COVID in utero in the next five years, according to researchers Dr. Lindsay Fourman and Dr. Andrea Edlow, both from Massachusetts General Hospital in Boston.
“In the current study, we look for the first time at longitudinal growth patterns among infants born to mothers with versus without COVID-19 during pregnancy,” Fourman said. “Such growth patterns may have key prognostic relevance for cardiometabolic disease risk later in life.”
The study results were published online March 29 in the Journal of Clinical Endocrinology & Metabolism.
These findings emphasize the importance of long-term follow-up of these children and the need for strategies to prevent COVID among pregnant women, Edlow said in a journal news release.
This isn't the first time researchers have found that a virus experienced by the mother affects children in utero.
“A growing body of work, including our own, has demonstrated that children born to mothers with HIV during pregnancy who are themselves HIV-negative are at increased risk of obesity, elevated blood pressure, dyslipidemia, and heart disease as compared to their unexposed peers,” Fourman said.
Other studies have found excess weight and heart disease later in life among those exposed to flu in the womb. “It is increasingly recognized that the maternal environment during pregnancy shapes the development of a growing fetus, which in turn may influence that individual's health trajectory over their life course,” Fourman said.
For 12 months, the researchers tracked 149 babies exposed to COVID in the womb and 127 infants who weren't exposed. The COVID group experienced a "steep, progressive rise" in BMI (body mass index), regardless of breastfeeding, that was not seen in the other babies.
The findings don't prove a cause and effect relationship, but they raise concerns.
Dr. Priya Rajan is an associate professor in the division of maternal-fetal medicine at Feinberg School of Medicine at Northwestern University in Chicago.
She said COVID seems to have a longer-lasting effect than other viruses that develop during pregnancy.
“One of the things that seems to be unique about COVID -- and this is in relation to what we are learning about long COVID in adults -- is that whatever inflammation it causes seems to last longer, and that might be why it's more pronounced, even what we're seeing in the placenta,” said Rajan, who was not part of the study.
It would be interesting to follow these infants for a long time, she said, and to continue to study this in newer populations.
"The two big questions I would have would be how did different variants affect things differently? And then the other huge thing I would want to know is how much does vaccination mitigate these risks?” said Rajan.
She said she's a strong advocate for protecting women and their babies with vaccination.
Also, if families realize their children could be predisposed to metabolic disorders like diabetes, perhaps they could build healthier habits to mitigate some of the risks, Rajan said.
Although the earlier Delta variant brought more severe fetal complications in the short-term, "COVID infection isn't innocuous," Rajan stressed.
Moreover, "it can have effects even if you're not that symptomatic. Even if you're not that sick from it during pregnancy, it can be having an effect on your pregnancy that we can't see," she noted.
"Because of that, taking whatever measures we can to mitigate that risk, including vaccination, is important," Rajan added.
While this study may suggest an increased risk of cardiometabolic disease later in life among the global population, Fourman said it's important to remember this study only looked at growth trajectories up to age 1 year.
“This work cannot yet address whether these children will go on to develop obesity, diabetes or cardiovascular disease in the long-term. Nonetheless, the pattern of infant growth among exposed individuals raises initial concern,” Fourman said.
Pediatricians should view the child's growth and metabolic risk factors with this in mind, the authors said, noting larger, longer studies are needed
The U.S. Centers for Disease Control and Prevention has more on lingering impacts from COVID-19.
SOURCES: Lindsay Fourman, MD, endocrinologist, metabolism unit, Massachusetts General Hospital, Boston; Priya Rajan, MD, director, diagnostic ultrasound and associate professor, maternal-fetal medicine, obstetrics and gynecology, Feinberg School of Medicine, Northwestern University, Chicago; Journal of Clinical Endocrinology & Metabolism, study and news release, March 29, 2023