Increased Insulin Levels Independent of Gestational Overweight in Women with Preeclampsia

BackgroundThe etiology of preeclampsia is unknown. It is controversial whether insulin resistance (IR) is present in preeclamptic patients, and it is unclear if hyperinsulinemia is dependent upon being overweight during pregnancy or on preeclampsia per se.MethodsWe performed a cross-sectional study in 140 pregnant patients and compared serum insulin concentrations. These women, 18–40 years old, were classified into four groups: 1) overweight patients with mild preeclampsia (n = 21), 2) overweight patients without preeclampsia (n = 23), 3) non-overweight patients with mild preeclampsia (n = 48), and 4) non-overweight patients without preeclampsia (n = 48). An oral glucose tolerance test (OGTT) was performed in all patients between 29 and 40 weeks of gestation. Blood samples were taken at 0, 60, 120 and 180 min after 100 g oral glucose to measure serum glucose and insulin levels.ResultsBasal and postload OGTT glucose values and basal insulin levels were similar in all groups. However, insulin levels at 60, 120 and 180 min were significantly higher (p = 0.009, p = 0.009, p = 0.046, respectively) in overweight patients with preeclampsia than in those without. Insulin levels at 60 and 180 min were also higher (p = 0.024, p = 0.023, respectively) in non-overweight patients with preeclampsia than in those without. The area under the curve (AUC) for glucose was not significantly different between both groups of overweight patients or between non-overweight patients with or without preeclampsia. In contrast, the AUC of insulin was significantly higher in preeclamptic patients in both overweight (p = 0.004) and non-overweight (p = 0.024) groups than in overweight and non-overweight groups without preeclampsia, respectively.ConclusionsIncreased insulin levels observed in mild preeclamptic patients were independent of overweight-related hyperinsulinemia.