Pregnancy Loss and the Risk of Myocardial Infarction, Stroke, and All-Cause Mortality: A Nationwide Partner Comparison Cohort Study.

Abstract

Background Pregnancy loss has been associated with myocardial infarction, stroke, and all-cause mortality in women through unknown mechanisms. The aim of this study was to examine these associations in women and their male partners. Methods and Results In this register-based cohort study, all people born between 1957 and 1997, residing in Denmark between 1977 and 2017, and with a registered partner of the opposite sex were eligible for inclusion. Male partners through cohabitation, marriage, or paternity constituted the male cohort. Exposure to pregnancy loss was categorized as follows: 0, 1, 2, or ≥3 pregnancy losses. The outcomes of interest were myocardial infarction, stroke, and all-cause mortality. The Cox proportional hazards model estimated hazard ratios (HRs), adjusted for age, calendar year, parity, and parental history of myocardial infarction or stroke. During follow-up, 1 112 507 women experienced 4463 events of myocardial infarction compared with 13 838 events among 1 120 029 male partners. With the no pregnancy loss group as reference, the adjusted HRs of myocardial infarction in the female cohort after 1, 2, and ≥3 pregnancy losses were as follows: 1.1 (95% CI, 1.0-1.2), 1.3 (95% CI, 1.1-1.5), and 1.4 (95% CI, 1.1-1.8), respectively. In the male partner cohort, the corresponding estimates were 1.0 (95% CI, 1.0-1.1), 1.1 (95% CI, 1.0-1.2), and 1.0 (95% CI, 0.8-1.2), respectively. The outcome of stroke showed similar results. Pregnancy loss was not significantly associated with increased mortality in either sex. Conclusions Pregnancy loss or stillbirth was significantly associated with myocardial infarction and stroke in women but not their male partners. Pregnancy loss or stillbirth was not significantly associated with all-cause mortality in women or male partners.