Division of Epidemiology of Chronic Diseases and Vulnerable Populations, Department of Quantitative Health Sciences
Cardiovascular Diseases | Cardiovascular System | Female Urogenital Diseases and Pregnancy Complications | Reproductive and Urinary Physiology | Women's Health
OBJECTIVES: Pregnancy, menses and menopause are related to fluctuations in endogenous sex hormones in women, which cumulatively may alter cardiac electrical conduction. Therefore, we sought to study the association between number of pregnancies and reproductive period duration (RD, time from menarche to menopause) with ECG intervals in the Women's Health Initiative Clinical Trials.
DESIGN: Secondary analysis of multicentre clinical trial.
PRIMARY OUTCOME MEASURES: ECGintervals: PR interval, P-wave duration, P-wave dispersion, QTc interval.
PARTICIPANTS: n=40 687 women (mean age=62 years) participating in the Women's Health Initiative Clinical Trials. 82.5% were white, 9.3% black, 4% Hispanic and 2.7% Asian.
METHODS: In primary analysis, we employed multivariable linear regression models relating number of pregnancies and RD with millisecond changes in intervals from enrolment ECG. We studied effect modification by hormone therapy use.
RESULTS: Among participants, 5+ live births versus 0 prior pregnancies was associated with a 1.32 ms increase in PR interval (95% CI 0.25 to 2.38), with a graded association with longer QTc interval (ms) (none (prior pregnancy, no live births)=0.66 (-0.56 to 1.88), 1=0.15 (-0.71 to 1.02), 2-4=0.25 (-0.43 to 0.94) and 5+ live births=1.15 (0.33 to 1.98), p=0.008). RD was associated with longer PR interval and maximum P-wave duration (but not P-wave dispersion) among never users of hormone therapy: (PR (ms) per additional RD year: 0.10 (0.04 to 0.16); higher P-wave duration (ms): 0.09 (0.06 to 0.12)). For every year increase in reproductive period, QTc decreased by 0.04 ms (-0.07 to -0.01).
CONCLUSIONS: An increasing number of live births is related to increased and RD to decreased ventricular repolarisation time. Both grand multiparity and longer RD are related to increased atrial conduction time. Reproductive factors that alter midlife cardiac electrical conduction system remodelling in women may modestly influence cardiovascular disease risk in later life.
TRIAL REGISTRATION NUMBER: NCT00000611.
ECG, adult cardiology, menopause, pregnancy, women
Rights and Permissions
© Author(s) (or their employer(s)) 2018. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ. This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.
DOI of Published Version
BMJ Open. 2018 Aug 17;8(8):e019129. doi: 10.1136/bmjopen-2017-019129. Link to article on publisher's site
Parikh NI, Kapphahn K, Hedlin H, Olgin JE, Allison MA, Magnani JW, Ryckman KR, Waring ME, Perez MV, Howard BV. (2018). Effects of reproductive period duration and number of pregnancies on midlife ECG indices: a secondary analysis from the Women's Health Initiative Clinical Trial. Open Access Articles. https://doi.org/10.1136/bmjopen-2017-019129. Retrieved from https://escholarship.umassmed.edu/oapubs/3585
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License