THE RELATIONSHIP BETWEEN ABNORMAL GLUCOSE-TOLERANCE AND HYPERTENSIVE DISORDERS OF PREGNANCY IN HEALTHY NULLIPAROUS WOMEN

OBJECTIVE: The study's aim was to determine whether healthy nulliparou s women with abnormal glucose tolerance during pregnancy are at increa sed risk for development of pregnancy-associated hypertension or preec lampsia. STUDY DESIGN: A series of 4589 healthy nulliparous women from 5 university centers were evaluated prospectively to determine whethe r calcium supplementation would prevent preeclampsia. Pregnancy-associ ated hypertension was a diastolic blood pressure greater than or equal to 90 mm Hg on 2 occasions 4 hours to 1 week apart. Pregnancy-associa ted proteinuria was proteinuria greater than or equal to 1+ by dipstic k testing on 2 occasions 4 hours to 1 week apart, proteinuria;greater than or equal to 300 mg/24 h, a protein to creatinine ratio of greater than or equal to 0.35, or a single dipstick measurement of greater th an or equal to 2+. Preeclampsia was defined as pregnancy-associated hy pertension and pregnancy-associated proteinuria documented within 7 da ys of each other. Normal glucose tolerance was a plasma glucose level <140 mg/dL 1 hour after a 50-g oral glucose challenge. Abnormal glucos e tolerance was a plasma glucose level greater than or equal to 140 mg /dL 1 hour after a 50-g oral glucose challenge followed by a 9-hour 10 0-g oral glucose tolerance test yielding <2 abnormal values. Gestation al diabetes mellitus was a plasma glucose level greater than or equal to 200 mg/dL 1 hour after a 50-g oral glucose challenge in the absence of an oral glucose tolerance test or greater than or equal to 2 abnor mal plasma glucose values in a 3-hour 100-g oral glucose tolerance tes t (greater than or equal to 105 mg/dL fasting, greater than or equal t o 190 mg/dL at 1 hour, greater than or equal to 165 mg/dL at 2 hours, or greater than or equal to 145 mg/dL at 3 hours). For purposes of thi s study women with preeclampsia were excluded from the category of pre gnancy-associated hypertension. RESULTS: Calcium supplementation did n ot prevent pregnancy-associated hypertension or preeclampsia. Oi 3689 women with complete glucose testing data, 227 (6%) had abnormal glucos e tolerance and 81 (2%) had gestational diabetes mellitus. Compared wi th women with normal glucose tolerance, women with abnormal glucose to lerance were significantly older, had greater body mass index,and were more likely to be white non-Hispanic, to smoke, and to have private m edical insurance. Among women with gestational diabetes mellitus, afte r adjustment for clinical center the relative risks of preeclampsia an d of all hypertensive disorders were increased (relative risk 1.67, 95 % confidence interval 0.92-3.05, and relative risk 1.54, 95% confidenc e interval 1.28-2.11, respectively). Risk ratios were not substantiall y reduced after further adjustment for race and body mass index (odds ratios 1.41 and 1.48, respectively). Even within the normal range, mul tivariate analysis demonstrated that the level of plasma glucose 1 hou r after a 50-g oral glucose challenge was an important predictor of pr eeclampsia. CONCLUSION: Even within the normal range, the level of pla sma glucose 1 hour after a 50-g oral glucose challenge was positively correlated with the likelihood of preeclampsia. Women with gestational diabetes mellitus were at increased risk for hypertensive disorders d uring pregnancy after adjustment for clinical center, race, and body m ass index, although the increase was not statistically significant. Th ese findings suggest that insulin resistance may play a role in the pa thogenesis of the hypertensive disorders of pregnancy.