in a new analysis.
This “exaggerated growth pattern observed among infants with COVID-19 exposure may in some cases be a catch-up response to a prenatal growth deficit,” Mollie W. Ockene and colleagues wrote in a report published recently in the Journal of Clinical Endocrinology & Metabolism.
But given that lower birth weight and accelerated postnatal weight gain are risk factors for cardiometabolic disease, the findings “raise concern” about whether children born to mothers with prenatal COVID-19 go on to develop obesity, diabetes, or cardiovascular disease, senior coauthors Andrea G. Edlow, MD, and Lindsay T. Fourman, MD, of Massachusetts General Hospital, Boston, told this news organization.
Further studies in larger numbers of patients with longer follow-up and detailed assessments are needed, the researchers said, but this points to “a potentially increased cardiometabolic disease risk for the large global population of children with in utero COVID-19 exposure.”
It will be “important for clinicians caring for children with in utero exposure to maternal COVID-19 to be aware of this history,” Dr. Edlow and Dr. Fourman added, “and to view the child’s growth trajectory and metabolic risk factors in a holistic context that includes this prenatal infection exposure.”
COVID-19 vaccination important during and prior to pregnancy
The study also underscores the importance of primary prevention of COVID-19 among women who are contemplating pregnancy or who are already pregnant, the researchers noted, “including the need for widespread implementation of protective measures such as indoor masking and COVID-19 vaccination and boosting during or prior to pregnancy.”
Dr. Edlow and Dr. Fourman added, “Given the disproportionate impact that COVID-19 has had on historically marginalized populations, adverse health outcomes following in utero exposure to maternal COVID-19 may threaten to widen existing disparities in child health.”
On the other hand, although “COVID-19 vaccination rates lagged behind in minority populations following the initial vaccine rollout,” they noted, “these differences have fortunately narrowed over time, particularly for Hispanic individuals, though they do still persist in the Black population,” according to a recent report.
BMI trajectories during first year of life
In utero exposure to COVID-19 has been linked to fetal/neonatal morbidity and mortality, including stillbirth, preterm birth, preeclampsia, and gestational hypertension, but less is known about infant outcomes during the first year of life.
The researchers aimed to compare weight, length, and BMI trajectories over the first year of life in infants with, versus without, in utero exposure to COVID-19.
They identified 149 infants with in utero exposure to COVID-19 and 127 unexposed infants; all were born between March 30, 2020, and May 30, 2021, to mothers who participated in the Mass General Brigham COVID-19 Perinatal Biorepository.
The study excluded infants whose mothers received the vaccine (n = 5) or who had unclear vaccination status during pregnancy (n = 4) to reduce sample heterogeneity.
At the time of the study, few women had received the COVID-19 vaccine because vaccines were approved by the Food and Drug Administration for emergency use in December 2020 and the CDC recommended them for all pregnant women much later, in August 2021.
The researchers examined the weight, length, and BMI of the infants at birth, and at 2, 6, and 12 months, standardized using World Health Organization (WHO) growth charts.
Compared with mothers who did not have COVID-19 during pregnancy, those who had COVID-19 were younger (mean age, 32 vs. 34 years) and had a higher earliest BMI during pregnancy (29 vs. 26 kg/m2) and greater parity (previous births, excluding the index pregnancy, 1.2 vs. 0.9), and they were more likely to be Hispanic or Black and less likely to have private insurance.
Compared with infants exposed to COVID-19 in utero, infants who were not exposed were more likely to be male (47% vs. 55%).
Both infant groups were equally likely to be breastfed (90%).
Compared with the unexposed infants, infants born to mothers with prenatal COVID-19 had lower BMI z-scores at birth (effect size, −0.35; P = .03) and greater gain in BMI z-scores from birth to 12 months (effect size, 0.53; P = .03), but they had similar length at birth and over 12 months, after adjustment for maternal age at delivery, ethnicity, parity, insurance status, and earliest BMI during pregnancy, as well as infant sex, date of birth, and if applicable, history of breastfeeding.
The study received funding from the National Institutes of Health, Harvard Nutrition Obesity Research Center, Boston Area Diabetes Endocrinology Research Centers, American Heart Association, and Simons Foundation. Ms. Ockene has reported no relevant financial relationships. Dr. Edlow has reported being a consultant for Mirvie and receiving research funding from Merck outside the study. Dr. Fourman has reported serving as a consultant and receiving grant funding to her institution from Amryt outside the study. Disclosures for the other authors are listed with the article.