Excess maternal weight in 1st trimester linked to foetal fat accumulation: Study

The study, led by researchers at the National Institutes of Health (NIH), showed that foetuses in the womb may have more fat in their upper arm and the abdomen.

The findings, appearing in the American Journal of Clinical Nutrition, may be key to developing early intervention strategies to prevent adult obesity associated with heavier birth weight.

Excessive weight gain early in life is a known risk factor for adult obesity and related conditions, such as heart disease, high blood pressure, and diabetes. For the study, the researchers analysed data from an earlier study of more than 2,600 singleton pregnancies.

This included information on maternal weight before and during pregnancy and three-dimensional (3D) ultrasound scans (up to five) throughout pregnancy.

The results showed that pregnant people with excessive weight gain -- defined as more than 2 kilograms (about 4.4 pounds) in the first trimester -- had foetuses with larger abdominal circumferences.

Compared to women with adequate weight gain in their pregnancy, these babies in the womb also had more abdominal area and larger foetal arm fat thickness.

Further, the team reported that foetuses from the excessive weight gain group continued to have greater arm thickness and abdominal measurements through the end of pregnancy, even when weight gain was not considered excessive during the second and third trimesters.

In contrast, most previous studies have not examined foetal 3D measures during pregnancy and have only linked total weight gain across pregnancy, not just in the first trimester, with birth weight.

"The findings suggest that the timing of weight gain, instead of total weight gain, could be important for developing efforts to prevent excess foetal size and reduce the risk of heart disease and other conditions later in life," the researchers said.