Insulin sensitivity and insulin secretion in lean and obese normal pregnant women.

: An insulin-modified frequently sampled intravenous glucose tolerance test with minimal model analysis was performed in normal pregnant women between 28-32 weeks of gestation, to assess insulin sensitivity and insulin secretion. Insulin sensitivity in the pregnant group (no. 26) was reduced to approximately 50% that of nonpregnant group (no. 27) (p < 0.05). This increased insulin resistance was compensated by an enhancement of the first phase of insulin secretion, which was increased more than twofold in the pregnant women when compared with the nonpregnant women (p < 0.05). There was a trend toward greater insulin resistance and insulin secretion in the obese pregnant women (no. 7) as compared with the lean pregnant women (no. 19) although this difference was not statistically significant. Our findings confirm that late pregnancy is a state of physiologic insulin resistance compensated by an increase of insulin secretion.