Glucose intolerance as a predictor of hypertension in pregnancy

Insulin resistance is associated with and may be causal in essential hypertension, but the relation between insulin resistance and hypertension arising de novo in pregnancy is unclear. Transient hypertension of pregnancy (new-onset nonproteinuric hypertension of late pregnancy) is associated with a high risk of later essential hypertension and thus may have similar pathophysiology. To assess the association between glucose intolerance and subsequent development of proteinuric and nonproteinuric hypertension in pregnancy in women without underlying essential hypertension or overt glucose intolerance, we performed a retrospective 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) had significantly higher glucose levels on 50-g oral glucose loading test (P < .01) and a significantly higher frequency of abnormal glucose loading tests (> or = 7.8 mmol/L) (P < .01) than women who remained normotensive (n = 77). Relative glucose intolerance was particularly common in women who developed nonproteinuric hypertension. Women who developed hypertension also had greater prepregnancy body mass index (P < or = .0001) and baseline systolic and diastolic blood pressures (P < or = .0001 for both), although all subjects were normotensive at baseline by study design. However, after adjustment for these and other potential confounders, an abnormal glucose loading test remained a significant predictor of development of 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 higher insulin levels in women developing hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)