LAUSR

It was previously observed that maternal iron supplementation in pregnancy was associated with increased offspring size and adiposity at birth, possibly mediated through increased risk of gestational diabetes. In this study we explored associations of maternal iron supplementation in pregnancy with postnatal offspring growth in infancy and indices of cardiometabolic disease risk factors such as glucose tolerance, insulin sensitivity and blood pressure in mid-childhood (at ~9.5 years of age) in the Cambridge Baby Growth Study. In infancy adiposity-promoting associations with maternal iron supplementation in pregnancy were evident at 3 months of age (e.g. mean difference in skinfold thickness: {beta}=+0.15 mm, p=0.02, in n=341 whose mothers supplemented versus 222 that did not; waist circumference: {beta}=+0.7 cm, p=0.04, in n=159 and 78, respectively) but differences lessened after this time (e.g. 3-12 month change in mean difference in skinfold thickness: {beta}=-0.2 mm, p=0.03, in n=272 and 178, respectively). At ~9.5 years of age associations with maternal iron supplementation in pregnancy were not evident for markers of growth, glucose tolerance, insulin sensitivity or secretion. However, children whose mothers supplemented with iron in pregnancy had lower mean arterial blood pressures ({beta}=-1.0 mmHg, p=0.03, in n=119 and 78, respectively). These results suggest that most of the associations of maternal iron supplementation in pregnancy on growth and adiposity evident at birth disappear during infancy, but there may be some evidence of long-term nutritional programming evident later in childhood.