Maternal carbohydrate metabolism and its relationship to fetal growth and body composition.

OBJECTIVE

Our purpose was to correlate maternal carbohydrate metabolism and parental morphometric measurements with neonatal birth weight, body composition, and placental weight.

STUDY DESIGN

Sixteen singleton (six control and 10 abnormal glucose tolerance) infants had placental weight, birth weight, and estimates of body composition performed within 24 hours of birth. Independent variables considered were (1) maternal and paternal demographic and morphometric measures, (2) neonatal sex and gestational age, and (3) estimates of maternal carbohydrate metabolism, including basal hepatic glucose production, insulin response, and insulin sensitivity. All metabolic measurements were performed before conception and in early (12 to 14 weeks) and late (34 to 36 weeks) gestation. Best-fit stepwise regression analysis was used to relate the independent variables with placental weight, neonatal birth weight, fat-free mass, and fat mass.

RESULTS

Insulin sensitivity in late gestation had the strongest correlation with placental weight (R2 = 0.28), neonatal birth weight (R2 = 0.28), and fat-free mass (R2 = 0.33). In contrast, insulin sensitivity before conception had the best correlation with neonatal fat mass (R2 = 0.15). Including all significant independent variables in the model improved the correlations for placental weight (R2 = 0.58), birth weight (R2 = 0.48), fat-free mass (R2 = 0.53), and fat mass (R2 = 0.46).

CONCLUSION

Maternal insulin sensitivity had stronger correlations with fetoplacental growth in comparison with maternal demographic or morphometric factors.