Association of Number of Live Births With Electrocardiographic and Cardiac Structural Changes

Abstract

Background Pregnancy is a major life event unique to women and leads to significant hemodynamic, hormonal, and metabolic changes. The purpose of this study was to use the DHS (Dallas Heart Study), a multiethnic population-based cohort study of Dallas county adults, to evaluate the association between number of live births and cardiac magnetic resonance imaging and ECG parameters later in life. Methods and Results Women were included if they had data on self-reported live births and ECG or cardiac magnetic resonance imaging measurements. The 3014 women were stratified by number of live births: 0, 1, 2, 3, 4, and ≥5. Higher number of live births was associated with larger left ventricular (LV) end-diastolic volume (β, 1.31±0.41; P<0.01), LV end-systolic volume (β, 0.83±0.24; P<0.01), and LV mass (β, 1.13±0.49; P=0.02) and lower LV ejection fraction (β, -0.004±0.0014; P<0.01). Increasing parity was associated with longer PR intervals (β, 1.07±0.38; P<0.01). Subgroup analysis by race demonstrated that the association between number of live births and magnetic resonance imaging parameters (LV end-diastolic volume, LV end-systolic volume, and LV ejection fraction) only remained significant in Black women (P value for interaction <0.05). Conclusions Increasing number of live births was associated with electrocardiographic and cardiac structural changes in a multiethnic population. When stratified by race and ethnicity, magnetic resonance imaging structural changes only remained significant in Black participants. Whether these changes are pathologic and increase the risk of heart failure or arrhythmias in multiparous women warrants further investigation.

Keywords: ECG; cardiac magnetic resonance imaging; cardiovascular risk factors; parity; women's health.

Figure Figure.. Least square means for the association of PR interval and cardiac MRI variables with number of live births.

Least square means for ECG and cardiac MRI parameters and their association with increasing levels of parity in fully adjusted models for age, race, income, education level, hypertension, smoking, and either body mass index (ECG parameters) or body surface area (cardiac MRI parameters). A, PR interval with increasing levels of parity. B, Left ventricular (LV) mass with increasing levels of parity. C, LV end‐diastolic volume (LVEDV) with increasing levels of parity. D, LV end‐systolic volume (LVESV) with increasing levels of parity. MRI indicates magnetic resonance imaging.