GLUCOSE-INTOLERANCE AS A PREDICTOR OF HYPERTENSION IN PREGNANCY

Insulin resistance is associated with and may be causal in essential h ypertension, but the relation between insulin resistance and hypertens ion arising de novo in pregnancy is unclear. Transient hypertension of pregnancy (new-onset nonproteinuric hypertension of late pregnancy) i s associated with a high risk of later essential hypertension and thus may have similar pathophysiology. To assess the association between g lucose intolerance and subsequent development of proteinuric and nonpr oteinuric hypertension in pregnancy in women without underlying essent ial hypertension or overt glucose intolerance, we performed a retrospe ctive case-control study comparing glucose levels on routine screening for gestational diabetes mellitus among women subsequently developing hypertension. Women who developed hypertension in pregnancy (n=97) ha d significantly higher glucose levels on 50-g oral glucose loading tes t (P<.01) and a significantly higher frequency of abnormal glucose loa ding tests (greater than or equal to 7.8 mmol/L) (P<.01) than women wh o remained normotensive (n=77). Relative glucose intolerance was parti cularly common in women who developed nonproteinuric hypertension. Wom en who developed hypertension also had greater prepregnancy body mass index (P less than or equal to.0001) and baseline systolic and diastol ic blood pressures (P less than or equal to.0001 for both), although a ll subjects were normotensive at baseline by study design. However, af ter adjustment for these and other potential confounders, an abnormal glucose loading test remained a significant predictor of development o f hypertension (P<.05) and, specifically, nonproteinuric hypertension in pregnancy (P<.01). Among a subgroup of women in whom insulin levels were also measured (n=80), there was a nonsignificant trend toward hi gher insulin levels in women developing hypertension. These results su ggest that relative glucose intolerance is associated with an increase d risk of new-onset hypertension in pregnancy, particularly the nonpro teinuric type, and indirectly support the hypothesis that insulin resi stance may play a role in the pathogenesis of this disorder.