Ovulatory and anovulatory cycle phase influences on QT interval dynamics during the menstrual cycle

Borna Naderi; Lauren Yee; Sonia Shirin; Jerilynn C Prior; Christopher Cheung; Brianna Davies; Andrew D Krahn

doi:10.1371/journal.pone.0320846

Menstrual Cycle · Cycle Physiology

Ovulatory and anovulatory cycle phase influences on QT interval dynamics during the menstrual cycle

Naderi B, Yee L, Shirin S, Prior JC, Cheung C, Davies B, Krahn AD

Published May 16, 2025 PloS one, 20(5), e0320846

DOI 10.1371/journal.pone.0320846 PMID 40378165 PMC PMC12083801

RRM Academy Synopsis

QT interval changes minimally between cycle phases in healthy women

The heart's QTc interval changed minimally between cycle phases in 62 healthy women. This cohort study tracked each woman's heart rhythm in the follicular phase, then again later in her cycle. Cycles with ovulation showed no meaningful change. Cycles without ovulation showed a small, nonsignificant lengthening before her period.

Study at a glance, prospective cohort of 62 healthy women: QTc changed minimally between cycle phases. Source: Naderi B et al., 2025, PMID 40378165.

Key Findings

In 26 ovulatory cycles, mean QTc was 383.0 msec in the mid-follicular phase and 382.6 msec in the luteal phase (P = .859).
In 36 anovulatory cycles, mean QTc was 381.7 msec in the mid-follicular phase and 385.0 msec in the premenstrual phase (P = .166).
A meta-analysis of four studies with 65 participants found a random-effects weighted mean QTc 1.67 msec shorter in the luteal phase (95% CI: −3.52; 6.86, P = .53).
Heart rate rose by more than 5 beats per minute from the follicular phase to the luteal or premenstrual phase in both groups (P < .05).
Of 82 women enrolled, 62 had complete paired data: 26 ovulatory cycles (17 with luteal phases of 10 days or longer, nine shorter) and 36 anovulatory cycles.

Interpretation

This cohort study followed 62 healthy women aged 19 to 35. Each woman had heart tracings in the follicular phase, then again later in the cycle. Quantitative Basal Temperature charting showed whether each cycle was ovulatory. None had used hormonal birth control in the prior three months. The authors link the small lengthening in cycles without ovulation to longer estrogen exposure without progesterone's balancing effect. They note they did not directly measure estrogen or progesterone levels. The results ruled out large QTc changes that would signal arrhythmia risk. The findings support larger studies of how ovulation affects the heart's electrical cycle.

RRM Context

Cycles about a month apart did not mean ovulation had occurred. Of the 62 women, 36 had cycles without ovulation. The authors link this to stressors tied to the pandemic. First-morning temperature charting is what revealed which cycles were ovulatory. Restorative reproductive medicine is built on cycle charting and root-cause care. It treats ovulatory status as a measurable fact.

Our editorial summary of this paper, not the article's abstract.

Abstract

Background

Ovarian hormones affect cardiovascular health yet few sufficient-sized studies with reliable ovulatory documentation have assessed the QTc-hormonal relationship. This study investigated QTc changes across ovulatory and anovulatory menstrual cycle phases.

Methods

This prospective cohort investigation, a cardiac sub-study of the Menstruation and Ovulation Study 2 (MOS2), involved 62 healthy, regularly menstruating community-dwelling women during spontaneous menstrual cycles. Electrocardiographic recordings were obtained within-woman during different cycle phases: mid-follicular for all, and luteal (ovulatory) or premenstrual (anovulatory), documented by the validated Quantitative Basal Temperature© method. Fridericia's formula rate-corrected the QT interval (QTc). A subsequent meta-analysis was conducted, pooling data from three additional studies to evaluate ovulatory follicular-luteal phase QTc changes.

Results

In the 26 ovulatory cycles, QTc minimally decreased from the mid-follicular to the luteal phases (383.0 ± 12.8 vs 382.6 ± 12.8 msec, P = .859). QTc in the 36 anovulatory cycles tended to increase from mid-follicular to premenstrual phases (381.7 ± 13.1 vs 385.0 ± 16.1 msec, P = .166). The meta-analysis in ovulatory cycles yielded a random-effects weighted mean QTc shortening of 1.67 msec (P = .53) in the luteal vs the follicular phase, aligning with our cohort data.

Conclusion

In confirmed ovulatory cycles, QTc changes were minimal, showing no meaningful luteal phase QTc shortening. QTc changes in anovulatory cycles were also insignificant, with a small QTc prolongation likely due to longer estradiol exposure not counterbalanced by progesterone. Under normal physiological conditions, QTc changes during the menstrual cycle are trivial, and menstrual status does not need to be considered when interpreting the QT interval.

Topics

Menstrual Cycle › Cycle Physiology › Hormonal Regulation · Reproductive Endocrinology › Ovarian Hormones › Progesterone

Borna Naderi, Lauren Yee, Sonia Shirin, Jerilynn C Prior, Christopher Cheung, Brianna Davies, Andrew D Krahn

B Naderi, L Yee, S Shirin, J Prior, Chris Cheung, C Cheung, B Davies, Andy Krahn, Drew Krahn, A Krahn

PMID 40378165 40378165 DOI 10.1371/journal.pone.0320846 10.1371/journal.pone.0320846 Naderi et al. 2025, Naderi 2025

Ovulatory and anovulatory cycle phase influences on QT interval dynamics during the menstrual cycle

QT interval changes minimally between cycle phases in healthy women

Key Findings

Interpretation

RRM Context

Abstract

Topics

By this author

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