The relationship between gestational weight gain, maternal upper-body subcutaneous fat changes and infant birth size: A pilot observational study amongst women with obesity.

Abstract

BACKGROUND\nIt is widely acknowledged that maternal obesity and excessive gestational weight gain (GWG) are associated with increased risk of fetal macrosomia and recent studies have suggested a role for the timing and composition of GWG.\n\n\nAIMS\nTo examine the effect of the rate of change in GWG and maternal upper-body subcutaneous fat on neonatal anthropometric outcomes in a pilot observational study amongst women with obesity.\n\n\nSTUDY DESIGN\nExpectant women with a body mass index (BMI) > 30\xa0kg/m2 at first antenatal appointment were recruited at 12\xa0weeks gestation. Maternal height, weight and skinfold thickness (SFT) measurements were collected at baseline and repeated at 28 and 36\xa0weeks gestation. Following delivery, World Health Organisation (WHO)-UK infant birthweight z-scores were calculated, and infant anthropometric measurements were obtained.\n\n\nRESULTS\nThe sum of upper body SFT measurements increased in mid-pregnancy (0.08 ± 0.71\xa0mm/week) and decreased in late pregnancy (-0.04 ± 1.17\xa0mm/week). After adjustment for maternal age, BMI and parity, mid- but not late- pregnancy GWG was positively associated with infant birthweight z-score (p<0.05), while mid- but not late-pregnancy changes in the sum of SFT were inversely associated with infant birthweight z-score (p<0.01).\n\n\nCONCLUSIONS\nThe present study suggests that mid- rather than late-pregnancy changes in weight and upper-body subcutaneous fat are associated with infant birthweight. Further research is required in larger, more diverse populations to explore whether pregnancy interventions aiming to improve maternal and offspring health can be personalised beyond BMI and GWG.