Intravenous glucose tolerance tests in women with twin pregnancy.

Carbohydrate metabolism was evaluated in 20 twin gestations and 20 singleton pregnancies. The groups were matched for age, parity, weight, height, and gestational age. Intravenous glucose tolerance tests were performed on all women in the third trimester of pregnancy using a glucose load of 0.5 g/kg body weight. Venous plasma glucose and insulin level were measured and statistically compared. The glucose disappearance rates (K) were not different in the two groups. No significant differences in the mean insulin or glucose responses were found between singleton and twin pregnancies. Thus, twin gestations are not at higher metabolic risk of gestational diabetes than are singleton pregnancies.