History of Pregnancy Loss and Risk for Higher Midlife Blood Pressure in Parous Females

Introduction: Pregnancy loss has been associated with later cardiometabolic conditions, potentially due to shared underlying etiology, but associations with midlife blood pressure (BP) remain unclear. Methods: We examined participants enrolled 1999-2002 in prospective Project Viva. At midlife ∼18 years after enrollment, we collected lifetime pregnancy history and measured BP. Exposures included any pregnancy loss or number of pregnancy losses. Outcomes were systolic and diastolic BP (SBP, DBP), and American Heart Association (AHA) BP categories. We performed multivariable regression adjusted for race and ethnicity, education, income, perceived body size at age 10 years, and age at outcome. Results: Of 623 participants, 33.7% reported pregnancy loss, 9.6% had elevated BP, and 34.8% had hypertension. Mean(±standard deviation) age was 50.7 ± 5.0 years, SBP 118.1 ± 15.6 mmHg, and DBP 74.8 ± 11.5 mmHg. In adjusted models, any pregnancy loss was associated with higher SBP (β = 2.25 mmHg, 95% confidence interval [CI]: -0.23, 4.78). Strongest associations with SBP were among those with first pregnancy loss ≥35 years (β = 5.58 mmHg, 95% CI: 1.76, 9.40 versus 0 pregnancy losses and first pregnancy <35 years). All associations with DBP were nonsignificant but similar in direction. For AHA outcomes, pregnancy loss was associated with higher risk for elevated BP (relative-risk ratio [RRR] = 2.93, 95% CI: 1.58, 5.43) but not with hypertension (RRR = 1.45, 95% CI: 0.95, 2.22) versus normotension. In models examining race and ethnicity, SBP was higher among non-Hispanic White and Hispanic individuals with pregnancy loss; non-Hispanic Black individuals had higher BP regardless of pregnancy loss status. Conclusions: History of pregnancy loss was associated with higher SBP and elevated BP category at midlife. These findings highlight reproductive history as an important consideration for cardiopreventive strategies and interventions.