Infant body composition in a randomised trial of a maternal nutritional supplement during preconception and pregnancy

In a multinational randomized controlled trial, we previously showed that maternal supplementation with myo-inositol, probiotics, and micronutrients was associated with reduced incidence of rapid infant weight gain and high body mass index (BMI) at two years among offspring. It was unclear whether these differences in weight gain and body mass were due to reduced adiposity. Therefore, we aimed to determine whether there were any differences in body composition.

Body composition was measured using bioelectrical impedance spectroscopy at six weeks, six months, one year, and two years among offspring born to mothers who received a nutritional intervention (n = 268) or control (n = 264) supplement preconception and during pregnancy.

There were no group-level differences in body composition, except at two years, when fat-free mass was greater among control offspring [adjusted mean difference (aMD) 0.14 kg, 95% confidence interval (CI) 0.03, 0.25, P = 0.012]. However, there were no differences in mean percentage fat mass (%FM) at any time. In both groups, rapid weight gain [Δ weight > 0.67 standard deviation (SD) from birth to one year] was associated with greater %FM (aMD 2.0% at six months, 2.0% at one year, 1.4% at two years) compared with those who did not have rapid weight gain. Likewise, high BMI (≥ 95 percentile) at two years was associated with greater %FM (aMD 2.5%).

A maternal nutritional intervention did not lead to differences in average offspring body composition in the first two years of life. However, fewer offspring from the supplemented group experienced rapid weight gain and high BMI, characterized by greater %FM.