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19: Maternal insulin resistance and preeclampsia

      Objective

      Insulin resistance (IR) is a hallmark of obesity and obesity is a consistent risk factor for preeclampsia. Our objective was to determine whether midtrimester maternal IR is associated with subsequent preeclampsia.

      Study Design

      This is a secondary analysis of a randomized controlled trial in 10,154 low-risk nulliparous women administered vitamin C and E or placebo daily from 9-16 weeks' gestation until delivery. Of these, 1,187 women had fasting plasma glucose and insulin tested between 22 and 26 weeks' gestation. IR was calculated by the homeostasis model assessment (HOMA-IR) derived from fasting plasma insulin (I) and glucose (G) values ((IxG/22.5)). Univariate and multivariate analyses controlling for maternal body mass index, race, treatment group, enrollment blood pressure and gestational age at sampling are presented.

      Results

      Eighty-five women developed preeclampsia and 592 remained normotensive without proteinuria. Fasting maternal G, I and HOMA-IR were significantly higher among those who subsequently developed preeclampsia compared with women who remained normotensive (p ≤ 0.01). Women with a mid-gestation fasting G, I, or HOMA-IR ≥ the 75th percentile were 1.5 to 1.9 fold more likely to develop preeclampsia (Table). Multivariate analyses confirmed midtrimester fasting I and HOMA-IR at ≥ the 75th percentile to be associated with preeclampsia. A HOMA-IR at ≥ the 75th percentile had a sensitivity of 40% for subsequent preeclampsia with a 25% false positive rate in normotensive women without proteinuria.
      TableMeasures ≥ 75th %ile
      MeasurePreE (%) N=85Normal (%) N=592ORAdjusted OR
      G37.626.51.7 [1.0-2.7]1.5 [0.9-2.5]
      I40.525.32.0 [1.3-3.2]1.8 [1.0-3.1]
      HOMA-IR40.524.82.1 [1.3-3.3]1.9 [1.1-3.2]
      PreE = preeclampsia

      Conclusions

      Maternal IR is associated with a significantly increased risk of subsequent preeclampsia.