Evidence map›Paper›PMID 30121588›Full record

Trial reportBMJ open2018

Effects of reproductive period duration and number of pregnancies on midlife ECG indices: a secondary analysis from the Women's Health Initiative Clinical Trial.

Nisha I Parikh, Kristopher Kapphahn, Haley Hedlin, Jeffrey E Olgin, Matthew A Allison, Jared W Magnani, Kelli R Ryckman, Molly E Waring, Marco Valentin Perez, Barbara V Howard

Registry-linked trialOpen access · goldAbstract readMulticenter StudyRandomized Controlled Trial
PubMed Full text at PMC Publisher
In one paragraph

Trial report in BMJ open, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT00000611 (Women's Health Initiative), which is not on this map. Cited by 6 papers.

0numbers the graph read from it
0cells of the map it votes in
6citing papers in PubMed
0.7field-weighted citation impact, top 26% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

NCT00000611 phase3completednot on this map

Women's Health Initiative (WHI)

TypeinterventionalSponsorNational Heart, Lung, and Blood Institute (NHLBI)ConditionsBone Diseases, Breast Neoplasms, Cardiovascular Diseases, Colonic NeoplasmsArmshormone replacement therapy, estrogens, progestins, estrogen replacement therapy, diet, fat-restricted
3 · Its place in the literature

Who cites it

6 citing papers in PubMed, 8 citations in OpenAlex.

  1. Commentary on the Predictive Value of P-Wave Dispersion and QTc Dispersion in Preeclampsia.Annals of noninvasive electrocardiology : the official journal of the International Society for Holter and Noninvasive Electrocardiology, Inc · 2026
    Article
  2. Article
  3. Article
  4. Article
  5. Infertility and Risk of Heart Failure in the Women's Health Initiative.Journal of the American College of Cardiology · 2022
    Article
  6. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

10 authors at 7 institutions in 1 country.

Nisha I ParikhDivision of Cardiology, University of California San Francisco, San Francisco, California, USA.
Kristopher KapphahnQuantitative Sciences Unit, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA.
Haley HedlinQuantitative Sciences Unit, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA.
Jeffrey E OlginDivision of Cardiology, University of California San Francisco, San Francisco, California, USA.
Matthew A AllisonDepartment of Family Medicine, University of California, San Diego, San Diego, California, USA.
Jared W MagnaniDivision of Cardiology, Boston University School of Medicine, Boston, Massachusetts, USA.ORCID 0000-0002-5075-3604
Kelli R RyckmanDepartment of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa, USA.
Molly E WaringDivision of Epidemiology of Chronic Diseases and Vulnerable Populations, Department of Quantitative Health Sciences, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
Marco Valentin PerezDepartment of Medicine, Stanford University School of Medicine, Stanford, California, USA.
Barbara V HowardMedStar Health Research Institute, Hyattsville, Maryland, USA.
Stanford University · USUniversity of California, San Francisco · USBoston University · USGeorgetown-Howard Universities Center for Clinical and Translational Science · USUniversity of California San Diego · USUniversity of Iowa · USUniversity of Massachusetts Chan Medical School · US

Funding

TRACE-COREU01HL105268 · NHLBI · UNIV OF MASSACHUSETTS MED SCH WORCESTER · PI KIEFE, CATARINA I. · 2010 to 2013
$5.8M
University of Massachusetts Center for Clinical and Translational ScienceKL2TR000160 · NCATS · UNIV OF MASSACHUSETTS MED SCH WORCESTER · PI LUZURIAGA, KATHERINE F · 2012 to 2014
$1.7M
Pregnancy complications, future cardiovascular disease risk factors and cardiovasR21HL115398 · NHLBI · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · PI PARIKH, NISHA INDRAVADAN · 2013 to 2014
$446k
American Heart Association-American Stroke Association 13CRP17350002NCATS NIH HHS KL2 TR000160NHLBI NIH HHS HHSN268201100046CNHLBI NIH HHS R21 HL115398NHLBI NIH HHS U01 HL105268WHI NIH HHS HHSN268201100001CWHI NIH HHS HHSN268201100002CWHI NIH HHS HHSN268201100003CWHI NIH HHS HHSN268201100004C
6 · The paper itself

Abstract

objectivesPregnancy, 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.

designSecondary analysis of multicentre clinical trial.

settingUSA. PRIMARY OUTCOME MEASURES: ECGintervals: PR interval, P-wave duration, P-wave dispersion, QTc interval.

participantsn=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.

methodsIn 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.

resultsAmong 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).

conclusionsAn 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; Post-results.

Indexed as

ElectrocardiographyAtrial RemodelingFemaleHormone Replacement TherapyHumansMenarcheMenopauseMiddle AgedParityTime Factorsadult cardiologyECGmenopausepregnancywomen

Identifiers

PMID30121588
PMCPMC6104755
OpenAlexW2914136610

What OpenQuestion holds

Textmetadata
LicenceCC BY-NC
Read underepoch 390

Registered trials

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.