Carbohydrate metabolism in gestational diabetes: Effect of chronic hypertension

Objective: To evaluate whether the coexistence of chronic hypertension and gestational diabetes mellitus (GDM) is characterized by a greater impairment of carbohydrate metabolism than GDM alone. Methods: Carbohydrate metabolism ol: eight women with chronic hypertensive GDM and 15 normotensive women with GDM was evaluated in the third trimester using the oral glucose tolerance test (GTT) and hyperinsulinemiceuglycemic clamp technique. Controls were ten normotensive, glucose-tolerant, pregnant women in the third trimester. Results: Insulin sensitivity of women with chronic hypertension and GDM was approximately twofold lower than those with GDM only (1.54 +/- 0.35 versus 4.15 +/- 0.31, P <.001) and approximately fivefold lower than controls (1.54 +/- 0.35 versus 7.65 +/- 0.66, P <.001). Women with chronic hypertension and concomitant GDM had higher insulin levels in response to GTT than controls (P <.001 repeated measures analysis of variance). In all subjects, mean arterial pressure (MAP) had a strong negative correlation with maternal insulin sensitivity (r = -0.62, P <.001), Significant correlation was also found between percent of body fat and insulin sensitivity (r =-0.53, P <.002). Those regressions were still significant when adjusted for percent of body fat and MAP. Conclusion: Gravidas with chronic hypertension and GDM are more insulin resistant than those with GDM alone. Blood pressure, in a population of pregnant women with normal and abnormal carbohydrate metabolism, is a stronger predictor of insulin resistance than adiposity. (Obstet Gynecol 1999;94:556-61. (C) 1999 by The American College of Obstetricians and Gynecologists.).