Increased fetal adiposity: a very sensitive marker of abnormal in utero development.

OBJECTIVE: Because offspring of women with gestational diabetes mellitus have an increased risk of obesity and diabetes mellitus as young adults, our purpose was to characterize body composition at birth in infants of women with gestational diabetes mellitus and normal glucose tolerance.

STUDY DESIGN: One hundred ninety-five infants of women with gestational diabetes mellitus and 220 infants of women with normal glucose tolerance had anthropometric measurements and total body electrical conductivity body composition evaluations at birth. Parental demographic, anthropometric, medical and family history data, and diagnostic glucose values were used to develop a stepwise regression model that related to fetal growth and body composition.

RESULTS: There was no significant difference in birth weight (gestational diabetes mellitus [3398+/-550 g] vs normal glucose tolerance [3337+/-549 g], P=.26) or fat-free mass (gestational diabetes mellitus [2962+/-405 g] vs normal glucose tolerance [2975+/-408 g], P=.74) between groups. However, infants of women with gestational diabetes mellitus had significantly greater skinfold measures (P=.0001) and fat mass (gestational diabetes mellitus [436+/-206 g] vs normal glucose tolerance [362+/-198 g], P=.0002) compared with infants of women with normal glucose tolerance. In the gestational diabetes mellitus group, although gestational age had the strongest correlation with birth weight and fat-free mass, fasting glucose level had the strongest correlation with neonatal adiposity.

CONCLUSION: Infants of women with gestational diabetes mellitus, even when they are average weight for gestational age, have increased body fat compared with infants of women with normal glucose tolerance. Maternal fasting glucose level was the strongest predictor of fat mass in infants of women with gestational diabetes mellitus. This increase in body fat may be a significant risk factor for obesity in early childhood and possibly in later life.