Insulin levels in the amniotic fluid and in maternal and fetal blood

The effects of excessive maternal weight gain during pregnancy (five cases) and of glucose infusion in the mother (five cases) on insulin levels are compared with the insulin levels in a control group (19 normal pregnancies) by radioimmunologic determination of insulin levels in the amniotic fluid and in maternal and fetal blood. The mean values for insulin in the control group were as follows: mother, 23.9 +/- 2.23 muU per ml; fetus, 9.86 +/- 2.11 muU per ml; and amniotic fluid, 5.08 +/- 2.27 muU per ml. In patients with excessive weight gain during pregnancy, maternal insulin mean values were 38.45 +/- 4.16 muU per ml; fetal, 19.99 +/- 9.8 muU per ml; and amniotic fluid, 11.25 +/- 2.58 muU per ml. After an infusion of 25 mg of glucose in the mother, the mean maternal insulin values were 53.6 +/- 13.74 muU per ml; fetal, 24.7 +/- 6.67 muU per ml; and amniotic fluid, 14.3 +/- 5.52 muU per ml. Insulin concentrations in maternal blood (p less than 0.001), fetal blood (p less than 0.001) and amniotic fluid (p less than 0.001) were higher in pregnancies with excessive weight gain as compared to those in the control group, whereas the glucose infusion in the mother increased the concentration of insulin in the three components studied.