THE RAPID INTRAVENOUS GLUCOSE TOLERANCE TEST IN PREGNANCY*

Abstract

Glucose tolerance in uncomplicated pregnancy was studied by the intravenous glucose tolerance test under standardized conditions, using 25 g of glucose and venous blood samples analyzed by the Nelson-Somogyi method. The rate of fall, k, obtained from a logarithmic plot of the experimental sugar levels between 10 and 60 minutes after the glucose injection, served as the index of tolerance. One hundred sixteen healthy women were tested, including 30 nonpregnant, 25 postpartum, and 61 pregnant subjects. Average group values of k, expressing blood glucose disappearance in per cent per minute, were: nonpregnant, 1.67; first trimester, 2.42; second trimester, 1.92; third trimester, 1.91; and postpartum, 1.58. Glucose tolerance was significantly elevated during pregnancy, particularly in the first trimester, with a prompt return to nonpregnant levels in the postpartum period. The glucose space was slightly increased in the third trimester. It is proposed that the k elevations result from both mild hyper insulinism and increased distribution volumes in pregnancy.