Long-Term Blood Pressure Changes Measured From Before to After Pregnancy Relative to Nonparous Women

Abstract

Objective To prospectively examine whether blood pressure changes persist after pregnancy among women of reproductive age. Methods Prospective, population-based, observational cohort of 2,304 (1,167 black, 1,137 white) women (aged 18–30) who were free of hypertension at baseline (1985–86) and reexamined up to six times at 2, 5, 7, 10, or 20 years later (2005–2006). We obtained standardized blood pressure measurements before and after pregnancies, and categorized women into time-dependent groups by the cumulative number of births since baseline within each time interval [0 births (referent); 1 interim birth and 2 or more interim births; non-hypertensive pregnancies]. The study assessed differences in systolic and diastolic blood pressures among interim birth groups using multivarible, repeated measures linear regression models stratified by baseline parity (nulliparous and parous) adjusted for time, age, race, baseline covariates (blood pressure, BMI, education, oral contraceptive use), and follow-up covariates (smoking, anti-hypertensive medications, oral contraceptive use, weight gain). Results Among nulliparas at baseline, mean (95%CI) fully adjusted systolic and diastolic blood pressures (mm Hg), respectively, were lower by −2.06 (−2.72 to −1.41) and −1.50 (−2.08 to −0.92) after one interim birth, and lower by −1.89 (−2.63 to −1.15) and −1.29 (−1.96 to −0.63) after 2 or more interim births compared with no births (all p-value <0.001). Among women already parous at baseline, adjusted mean blood pressure changes did not differ by number of subsequent births. Conclusion A first birth is accompanied by persistent lowering of blood pressure from preconception to years after delivery. Although the biologic mechanism is unclear, pregnancy may create enduring alterations in vascular endothelial function.

Cumulative Incidence of Hypertension by 55 Years of Age in Blacks and Whites: The CARDIA Study

“…During the Year 20, 25, and 30 study visits, BP was recorded using a standard automated BP measurement monitor (Omron model HEM907XL; Omron Healthcare, Inc, Lake Forest, IL). To ensure comparability between the 2 methods, BP measurements at the Year 20 and 25 study visits were calibrated to random‐0 sphygmomanometer values based on simultaneous readings from both devices using a Y connector on a subset (n=906) of CARDIA participants 13. At all study visits, each participant's arm circumference was measured at the midpoint between the acromion and olecranon of the right arm to determine the appropriate cuff size.…”

Long-Term Alteration in Maternal Blood Pressure and Renal Function After Pregnancy in Normal and Growth-Restricted Rats

“…A recent study in humans found that long-term maternal blood pressure was Ϸ2 mm Hg lower in parous women. 27 It was suggested that, rather than an effect of pregnancy, per se, human pregnancy may reflect a subset of women with better cardiovascular function. Evidence suggests that women who experienced complicated pregnancies were more likely to develop chronic hypertension in later life.…”

Parity as predictor of early hypertension during menopausal transition

“…It may result in permanent and not just temporary detrimental effects on the body and promote weight gain, insulin resistance and dyslipidemia in later life [8,9]. Hemodynamic adaptations during pregnancy include increases in cardiac output and blood volume and decreases in perfusion pressure and total systemic vascular resistance [4]. Several studies have considered the association between parity and the prevalence of hypertension in later life and results were conflicting [3,4,10,11].…”

“…Blood pressure is affected by a number of traditional cardiovascular risk factors such as age, family history and BMI, but also those parameters related to reproductive history may play a role in hypertension development [3]. Pregnancy produces marked alterations in vascular physiology [4][5][6] and may be considered as a temporary dip into the metabolic syndrome [7]. It may result in permanent and not just temporary detrimental effects on the body and promote weight gain, insulin resistance and dyslipidemia in later life [8,9].…”