Gravidity, blood pressure, and hypertension among white women in the Second National Health and Nutrition Examination Survey.
Gravidity and parity have been hypothesized as possible protective factors for hypertension in women, but results of previous studies have been conflicting; none of three U.S. studies has clearly demonstrated this relation. We studied the association of number of pregnancies to blood pressure and hypertension in a cross-sectional study of 4,626 white women, ages 20-74 years, examined in the Second National Health and Nutrition Examination Survey. In univariate analyses, neither mean systolic blood pressure, mean diastolic blood pressure, nor prevalence of hypertension varied systematically with the number of pregnancies. In multivariate analyses that included age, body size, smoking, oral contraceptive use, education, poverty status, and alcohol use, systolic blood pressure declined modestly with greater gravidity. The association of gravidity with systolic blood pressure was stronger for younger premenopausal women. The odds of hypertension also declined with each additional pregnancy as compared with no pregnancies: there was an odds ratio of 0.90 (95% confidence interval = 0.81-0.99) for premenopausal women and an odds ratio of 0.95 (95% confidence interval = 0.92-0.98) for postmenopausal women. These findings indicate a slight negative relation of number of pregnancies to both blood pressure and hypertension.
Ness
R B
RB
Clinical Epidemiology Unit, University of Pennsylvania, Philadelphia 15261.
Kramer
R A
RA
Flegal
K M
KM
D000328:Adult; D000368:Aged; D001794:Blood Pressure; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology* / Q000208:ethnology; D008593:Menopause; D008875:Middle Aged; D016017:Odds Ratio; D010298:Parity; D011247:Pregnancy / Q000706:statistics & numerical data*; D015995:Prevalence; D012044:Regression Analysis; D014481:United States / Q000453:epidemiology; D044465:White People