BOSTON – Maternal obesity and increased weight gain during pregnancy are associated with changes to newborns’ cardiometabolic markers, and these associations are largely independent of infant adiposity, according to new research findings.

Maternal obesity and weight gain during pregnancy are established risk factors for childhood obesity, but the reasons for this remain little understood.

In utero programming of infant metabolism may be occurring, providing reasons beyond fetal growth and fat accretion for the differences in lipid and hormonal profiles among infants, judging from the findings reported at the annual scientific sessions of the American Diabetes Association.

Presenting data from a cohort of 753 mother-infant pairs, Dominick J. Lemas, Ph.D., of the University of Colorado, Denver, said that samples of cord blood revealed “striking” associations.

Dr. Lemas and his colleagues found higher levels of cord blood glucose (P = .03), and leptin (P < .001) in newborns among mothers who gained more weight during pregnancy. Infants of women with higher body mass index when they became pregnant saw higher levels of leptin (P < .001) in cord blood and lower levels of HDL cholesterol (P = .05), even after adjusting for infant adiposity.

The leptin finding was particularly surprising, Dr. Lemas said. Leptin, a hormone that regulates food intake, energy output, and other functions, is synthesized by fatty tissues and therefore expected to be found in higher levels among infants with fatter body composition.

In this study, however, “the association actually became stronger when we adjusted for the adiposity of the infant,” he said.

The investigators looked carefully at cord blood lipids, including total and high-density lipoprotein (HDL) cholesterol, triglycerides, and free fatty acids. The finding that prepregnancy BMI was negatively associated with HDL cholesterol “was something very interesting for our group,” Dr. Lemas said at the conference. “In adults, abnormal lipid patterns are a very strong predictor of cardiovascular disease.”

The findings raise two main concerns, Dr. Lemas said. First, “what factors beyond maternal BMI and gestational weight gain contribute to the changes to these cardiometabolic biomarkers at delivery?” And second, he said, it remains to be seen if these markers persist or result in clinically meaningful differences: “It’s possible cord-blood biomarkers don’t predict the metabolic risk of these individuals a few years down the road.”

The investigators used data from Healthy Start, a cohort study funded by the National Institute of Diabetes and Digestive and Kidney Diseases. They disclosed no conflicts of interest, and the full paper on their findings will be published in the International Journal of Obesity.