Reproductive History and Endometriosis Among Premenopausal Women

Missmer SA, Stacey A. Missmer, Susan E. Hankinson, Hankinson SE, Donna Spiegelman, Spiegelman D, Barbieri RL, Robert L. Barbieri, Malspeis S, Susan Malspeis, Walter C. Willett, Willett WC, Hunter DJ, David J. Hunter
Obstetrics and gynecology · 2004 · vol. 104(5, Part 1) , pp. 965–974 · doi:10.1097/01.aog.0000142714.54857.f8 · PMID:15516386 · W2313825310
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This prospective study found that premenopausal women with earlier menarche and shorter menstrual cycles had higher endometriosis risk, while parity and longer lactation duration were associated with decreased risk.

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This prospective cohort study analyzed ten years of data from the Nurses' Health Study II to examine the temporal relationship between reproductive factors and endometriosis in premenopausal women. The researchers identified that a younger age at menarche and shorter menstrual cycle length during late adolescence were associated with an increased incidence of laparoscopically confirmed endometriosis, particularly among nulliparous individuals. Conversely, higher parity and longer duration of lactation within five years of the last birth were linked to a significantly decreased risk of developing the condition. This paper is centrally about endometriosis, specifically investigating how reproductive history influences disease risk in premenopausal women.

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Abstract

OBJECTIVE: To clarify the temporal complexities of the relation between reproductive factors and endometriosis. METHODS: We analyzed 10 years of prospective data from the Nurses' Health Study II cohort. Information was obtained through questionnaires sent every 2 years to 116,678 women aged 25-42 years when enrolled in 1989. Cox proportional hazards models were used to adjust for age, calendar time, and confounding variables. RESULTS: During 726,205 woman-years of follow-up, 1,721 cases of laparoscopically confirmed endometriosis were reported among women with no past infertility. Greater incidence was observed among women with an earlier age at menarche (rate ratio of 1.3 comparing menarche at age < 10 to age 12 years; 95% confidence interval [CI] 1.0-1.8; P value, test for trend < .001) and shorter cycle length during late adolescence (rate ratio of 1.3 comparing < 26 days to 26-31 days; 95% CI 1.1-1.5). Time to cycle regularity was not associated with risk. Among parous women, a linear decrease in risk was observed with number of liveborn children (rate ratio of 0.5 comparing > 3 with 2 children; 95% CI 0.4-0.7; P value, test for trend 23 months with never; 95% CI 0.1-0.4; P value, test for trend < .001). CONCLUSION: Hormonal and anatomical changes associated with menstruation and pregnancy may affect the rate of laparoscopically confirmed endometriosis. Within this cohort, risk was greatest among nulliparous women with earlier age at menarche and shorter menstrual cycles. Among parous women, parity and lifetime duration of lactation were associated with decreased risk.
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Objective

To clarify the temporal complexities of the relation between reproductive factors and endometriosis.

Methods

We analyzed 10 years of prospective data from the Nurses' Health Study II cohort. Information was obtained through questionnaires sent every 2 years to 116,678 women aged 25–42 years when enrolled in 1989. Cox proportional hazards models were used to adjust for age, calendar time, and confounding variables.

Results

During 726,205 woman-years of follow-up, 1,721 cases of laparoscopically confirmed endometriosis were reported among women with no past infertility. Greater incidence was observed among women with an earlier age at menarche (rate ratio of 1.3 comparing menarche at age < 10 to age 12 years; 95% confidence interval [CI] 1.0–1.8; P value, test for trend < .001) and shorter cycle length during late adolescence (rate ratio of 1.3 comparing < 26 days to 26–31 days; 95% CI 1.1–1.5). Time to cycle regularity was not associated with risk. Among parous women, a linear decrease in risk was observed with number of liveborn children (rate ratio of 0.5 comparing > 3 with 2 children; 95% CI 0.4–0.7; P value, test for trend 23 months with never; 95% CI 0.1–0.4; P value, test for trend < .001).

Conclusion

Hormonal and anatomical changes associated with menstruation and pregnancy may affect the rate of laparoscopically confirmed endometriosis. Within this cohort, risk was greatest among nulliparous women with earlier age at menarche and shorter menstrual cycles. Among parous women, parity and lifetime duration of lactation were associated with decreased risk.

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Condition tags

endometriosisinfertility

MeSH descriptors

Endometriosis Adult Endometriosis Female Humans Lactation Menarche Menstrual Cycle Parity Proportional Hazards Models Prospective Studies Risk Factors

Citation neighborhood

Papers in the corpus that this work cites (lower rings, blue) and that cite this one (upper rings, green). Dot size scales with the paper's in-corpus citation count — bigger dot = more influential within the endo/adeno field. Click a dot to open that paper. [ expand to 2 hops ] — adds papers reached through this work's immediate citers/citees. Heavier; up to 60 extra dots.

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