Infants of overweight or obese mothers grow more slowly

• Impact of maternal weight seen in infants at 3 months

• Inflammatory response to maternal fat may affect fetal development

A mother’s weight during pregnancy may affect her infant’s growth after birth, a new study finds. A small prospective cohort study reported online by the Journal of Pediatrics finds that maternal overweight or obesity decreases infants’ size and adipose tissue mass at age 3 months.

The study followed 97 nondiabetic mothers, of whom 59 were normal weight, 18 were overweight, and 20 were obese. Maternal prepregnancy weight was self-reported. Infants’ weight, length, and body composition were measured at ages 2 weeks and 3 months.

Infants’ growth did not differ at 2 weeks. By 3 months, infants of overweight or obese mothers had gained 11 oz less (P=.02), were nearly 0.5 in shorter (P=.01), and had 0.3 oz less fat mass (P=.01). Adjustment for breastfeeding status had no effect; adjustment for maternal smoking and glucose challenge results in a subset of 80% of participants also had no effect.

Fat is essential for infants’ brain development, so early deceleration in growth suggests the damaging consequences of obesity may begin even before birth. Although children of overweight or obese mothers generally catch up to children of normal-weight mothers, they are at higher risk of future overweight/obesity and accompanying health problems.

Researchers hypothesize that inflammatory responses involving a mother’s fat cells may have an impact on her developing fetus, affecting appetite and satiety responses and growth. The increased growth hormones delivered through fatty acids in utero may slow development of an infant’s pituitary gland and diminish its capacity to promote growth shortly after birth.

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