Affiliations

Advocate Aurora Research Institute

Abstract

Background/Significance:

A woman’s reproductive lifespan (age at menopause-age at menarche) is anchored within two significant physiological shifts. On average, women spend half their life in this phase and are susceptible to gynecological diseases.

Purpose:

The aim of the menopause (M2M) study is to examine the shift in reproductive lifespan.

Methods:

The M2M study included women (10-90 years) with a documented age at menarche and 1> annual encounter between 2014-2024 within a large Midwestern Health System (n=340,220). Demographics, gynecological conditions, and comorbidities were extracted from electronic health records. Descriptive statistics for continuous variables are presented as means and standard deviations and counts and percentages are used to describe categorical and dichotomous variables. Ages were stratified in quartiles by birth year: Q1(1924-1959), Q2 (1960-1972), Q3 (1973-1985), and Q4 (1986-2013). Linear regression (means, 95% confidence intervals [CI]) adjusting for race/ethnicity and earliest available BMI was used to determine association between birth year quartile and age at menarche. Survival analysis (Hazard ratio [HR], 95% CI) adjusting for age at menarche, parity, hysterectomy, body mass index, smoking, alcohol, hormone replacement therapy, hypertension, diabetes, depression, race/ethnicity, and marital status was used to examine association between birth year quartile and time to menopause.

Results:

Women were mostly non-Hispanic White (72%), never smokers (53%), with an average age of 45 years. Average age at menarche was 13 years, 55 years for menopause, while the average reproductive lifespan was 43 years. Model-adjusted age at menarche means were: Q1 (oldest) 12.63 (95% CI:12.63,12.67), Q2 12.72 (95% CI:12.71,12.74), Q3 12.50 (95% CI:12.49,12.52), and Q4 (youngest)12.30 (95% CI:12.29,12.32). Compared to Q1, Q2 had an adjusted difference of 0.08 years (0.06,0.09; p<.0001) while Q3 and Q4 had adjusted differences of -0.14 years (-0.16,-0.12; p<.0001) and -0.35 years (-0.37,-0.33; <.0001), respectively. Compared to Q1, Q2 (HR=1.03, 95% CI: 1.00-1.04), Q3 (HR=2.49, 95% CI: 2.39-2.59), and Q4 (HR=13.77, 95% CI: 10.67-17.78) had a shorter time to menopause.

Conclusion:

Age at menarche and menopause have decreased significantly over time, with women in the younger cohort experiencing menarche and reaching menopause at an earlier age. Further modeling is warranted to understand the impact of this shift on reproductive lifespan on women’s health.

Presentation Notes

Presented at Scientific Day; May 20, 2026; Milwaukee, WI.

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May 20th, 12:00 AM

Menarche to Menopause: The Impact of the Reproductive Lifespan on Gynecological Health

Background/Significance:

A woman’s reproductive lifespan (age at menopause-age at menarche) is anchored within two significant physiological shifts. On average, women spend half their life in this phase and are susceptible to gynecological diseases.

Purpose:

The aim of the menopause (M2M) study is to examine the shift in reproductive lifespan.

Methods:

The M2M study included women (10-90 years) with a documented age at menarche and 1> annual encounter between 2014-2024 within a large Midwestern Health System (n=340,220). Demographics, gynecological conditions, and comorbidities were extracted from electronic health records. Descriptive statistics for continuous variables are presented as means and standard deviations and counts and percentages are used to describe categorical and dichotomous variables. Ages were stratified in quartiles by birth year: Q1(1924-1959), Q2 (1960-1972), Q3 (1973-1985), and Q4 (1986-2013). Linear regression (means, 95% confidence intervals [CI]) adjusting for race/ethnicity and earliest available BMI was used to determine association between birth year quartile and age at menarche. Survival analysis (Hazard ratio [HR], 95% CI) adjusting for age at menarche, parity, hysterectomy, body mass index, smoking, alcohol, hormone replacement therapy, hypertension, diabetes, depression, race/ethnicity, and marital status was used to examine association between birth year quartile and time to menopause.

Results:

Women were mostly non-Hispanic White (72%), never smokers (53%), with an average age of 45 years. Average age at menarche was 13 years, 55 years for menopause, while the average reproductive lifespan was 43 years. Model-adjusted age at menarche means were: Q1 (oldest) 12.63 (95% CI:12.63,12.67), Q2 12.72 (95% CI:12.71,12.74), Q3 12.50 (95% CI:12.49,12.52), and Q4 (youngest)12.30 (95% CI:12.29,12.32). Compared to Q1, Q2 had an adjusted difference of 0.08 years (0.06,0.09; p<.0001) while Q3 and Q4 had adjusted differences of -0.14 years (-0.16,-0.12; p<.0001) and -0.35 years (-0.37,-0.33; <.0001), respectively. Compared to Q1, Q2 (HR=1.03, 95% CI: 1.00-1.04), Q3 (HR=2.49, 95% CI: 2.39-2.59), and Q4 (HR=13.77, 95% CI: 10.67-17.78) had a shorter time to menopause.

Conclusion:

Age at menarche and menopause have decreased significantly over time, with women in the younger cohort experiencing menarche and reaching menopause at an earlier age. Further modeling is warranted to understand the impact of this shift on reproductive lifespan on women’s health.

 

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