Menstrual bleeding, cycle length, and follicular and luteal phase lengths in women without known subfertility: A pooled analysis of three cohorts

Najmabadi S; Simonsen SE; Porucznik CA; Egger MJ; Stanford JB; Schliep KC

doi:10.1111/ppe.12644

Menstrual Cycle Cycle Physiology

Menstrual bleeding, cycle length, and follicular and luteal phase lengths in women without known subfertility: A pooled analysis of three cohorts

Najmabadi S, Simonsen SE, Porucznik CA, Egger MJ, Stanford JB, Schliep KC

Published May 2020 Paediatric and Perinatal Epidemiology, 34(3), 318-327

DOI 10.1111/ppe.12644 PMID 32104920 PMC PMC8495765

RRM Academy Synopsis

Cycle and ovulation timing varied widely in 581 women charting cycles

Cycle and phase timing varied widely in a pooled analysis of three charting cohorts. The 581 women had no known trouble getting pregnant. Ovulation was estimated on day 14 in about 9 out of 100 cycles, and the luteal phase lasted 14 days in about 10 out of 100. Cycles averaged 30.3 days.

Key Findings

The 581 women contributed 3,324 cycles. Mean cycle length was 30.3 days (SD 6.7, median 29), follicular phase 18.5 days (median 17), luteal phase 11.7 days (median 12).
Estimated ovulation fell on day 14 in 8.7% of cycles, and a 14-day luteal phase occurred in 9.7%. Overall, 96.5% of cycles had a mucus peak day and counted as ovulatory.
Women aged 30 or older with no prior births had shorter cycles than those under 30 (29.2 days, 95% CI 27.8, 30.7 vs 31.5 days, 95% CI 30.8, 32.2).
Within one woman, longest and shortest cycles differed by over 7 days in 43.0%; follicular phases by over 7 days in 41.7%; luteal phases by over 3 days in 58.8%.
A short luteal phase (under 10 days) appeared in 18.1% of cycles (95% CI 16.7, 19.5).

Interpretation

The authors pooled data from three earlier cohorts of women taught the Creighton Model FertilityCare System. Ovulation was inferred from each woman's own peak day of cervical mucus, and women with known fertility problems were excluded from the cohorts. The authors note that the clinical meaning of some individual findings is not yet fully established. The findings support larger studies of cycle and ovulation timing across more diverse populations.

RRM Context

The paper calls menstrual cycles measurable vital signs of reproductive health. Fertility awareness charting records each woman's own peak day of cervical mucus, so ovulation timing comes from her chart. A fixed calendar day such as day 14 matched fewer than 1 in 10 cycles here.

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

Abstract

Background

There is variability between women for days of menstrual bleeding, cycle lengths, follicular phase lengths, and luteal phase lengths, related to age and parity.

Objective

To describe total cycle length; anovulatory cycles; follicular and luteal phase lengths; and days and intensity of menstrual and non-menstrual bleeding in women without known subfertility over the course of 1 year.

Methods

581 women (3,324 cycles) with no known subfertility (18-40 years of age) were followed for up to 1 year. Women recorded vaginal bleeding and mucus discharge daily. We used the peak day of cervical mucus as the estimated day of ovulation and the last day of the follicular phase. We used generalised linear mixed models stratified by age and parity to describe menstrual cycle parameters.

Results

The majority of women were <30 years of age (74.5%), non-Hispanic White (88.6%), and nulliparous (70.4%). The mean menses length was 6.2 (1.5) days, median 6; cycle length 30.3 (6.7) days, median 29; follicular phase length 18.5 (6.5) days, median 17; and luteal phase length 11.7 (2.8) days, median 12. Nulliparous women aged ≥30 years vs nulliparous women aged <30 had shorter cycles (29.2 days, 95% confidence interval (CI) 27.8, 30.7 vs 31.5 days, 95% CI 30.8, 32.2) and shorter follicular phases (17.6 days, 95% CI 16.2, 18.9 vs 19.6 days, 95% CI 18.9, 20.2). Among all women, within-woman differences between the longest and shortest menses length >3 days, total cycle length >7 days, follicular phase >7 days, and luteal phase >3 days were found in 11.6%, 43.0%, 41.7%, and 58.8% of women, respectively.

Conclusions

Our findings confirm variability between women of menstrual cycle parameters related to age and parity, and also highlight within-woman variability in the follicular and luteal phases.

Topics

Menstrual Cycle › Cycle Physiology › Cycle Variability · Reproductive Endocrinology › Ovulation Physiology › Anovulation · Longevity and Reproductive Aging › Reproductive Aging › Cycle Changes With Age

Shahpar Najmabadi, Christina A Porucznik, Karen C Schliep, Joseph B Stanford

S Najmabadi, C Porucznik, K Schliep, Joe Stanford, Joey Stanford, J Stanford

PMID 32104920 32104920 DOI 10.1111/ppe.12644 10.1111/ppe.12644 Najmabadi et al. 2020, Najmabadi 2020

Keywords

Adult, Age Factors, Cohort Studies, Female, Follicular Phase/physiology, Humans, Luteal Phase/physiology, Menstrual Cycle/physiology, Menstruation/physiology, Ovulation/physiology, Parity/physiology, Reproductive Physiological Phenomena, United States, Women's Health, Follicular Phase, Luteal Phase, Menstrual Cycle, Menstruation, Ovulation, Peak Day

Menstrual bleeding, cycle length, and follicular and luteal phase lengths in women without known subfertility: A pooled analysis of three cohorts

Cycle and ovulation timing varied widely in 581 women charting cycles

Key Findings

Interpretation

RRM Context

Abstract

Topics

By this author

Related research

Keywords