Obstetric and metabolic implications of excessive gestational weight gain in pregnancy

OBJECTIVE: To compare maternal characteristics, obstetric outcomes and insulin resistance in a cohort of women subdivided into those who did and those who did not exceed the Institute of Medicine (IOM) gestational weight gain guidelines. METHODS: This is a prospective study of 621 women without diabetes. Concentrations of glucose, insulin and leptin were measured in early pregnancy and at 28 weeks. Ultrasound at 34 weeks assessed fetal anthropometry including abdominal wall width (AAW). At delivery birthweight was recorded and fetal glucose, C-peptide and leptin measured in cord blood. Insulin resistance was calculated using the HOMA equation. Outcomes in those who did and did not exceed IOM guidelines were compared. RESULTS: Overall, 267 women (43%) exceeded IOM guidelines and 354 (57%) did not. On 34-week ultrasound women with excessive weight gain had higher fetal weights (2681 ± 356 g vs. 2574 ± 331, P = 0.001) and fetal adiposity (AAW) (5.29 ± 1.3 vs. 4.8 ± 1.2, P = 0.001). Infant birthweight and birthweight centiles were also higher in those who exceeded the guidelines. There was no difference between the two groups in maternal insulin resistance in early pregnancy, but by 28 weeks those with excessive weight gain had higher maternal HOMA indices and higher maternal leptin concentrations. CONCLUSION: Excessive maternal gestational weight gain has significant implications for infant growth and adiposity, with potential implications for later adult health.