Insulin changes in preeclamptic women during pregnancy

The etiology of preeclampsia remains obscure. To study the role of insulin resistance in preeclampsia, we compared fasting insulin and glucose changes during the second and third trimesters in preeclamptic women with a normal control group.

In a nested case-control study, subjects were selected from a population-based cohort of 674 pregnant women from whom serum was collected for this study between the 20th and 24th week of gestation. For 16 women who developed preeclampsia (cases), 16 women who remained normotensive were selected as controls. Controls were matched with each case for pregestational body mass index, age, gestational age, and parity. Fasting glucose and insulin levels of the second trimester (20th to 24th weeks) of pregnancy were compared based on serological data. The comparisons were also carried out in the third trimester when preeclampsia occurred.

Fasting insulin levels increased from 15.3+/-1.3 microlU/mL to 25.3+/-1.4 microlU/mL between the second and third trimesters in the preeclamptic group (P<0.01) and from 10.4+/-0.9 microlU/mL to 16.2+/-1.3 microlU/mL in the control group (P<0.01). There was no significant change in glucose levels during pregnancy in either group.

Women who develop preeclampsia have higher insulin levels before clinical evidence of disease than women who remain normotensive during pregnancy. The increase in insulin levels in the third trimester was greater in preeclamptic than in non-preeclamptic women.