The incidence and prevalence of endometriosis in a United States population-based study .

The incidence and prevalence  of endometriosis in a United States population-based study .

This retrospective cohort study indicates that the incidence of endometriosis is less than the previous reports in the US.

Key Points


  • While the endometriosis incidence declined from 30,2% to 17,4/ 10.000 person-year, chronic pelvic pain complaints doubled and dysmenorrhea remained unchanged between 2006-2015 in the US.


  • The accurate incidence and prevalence of endometriosis in the USA are missing and these should be clarified among an unselected cohort for the assessment of diagnostic trends.

What's done here:

  • A retrospective cohort study to define the accurate incidence and prevalence of endometriosis in the US population was performed by electronic health record database between 2005-2016 in Washington State.
  • Primarily the annual incidence rates and the estimated prevalence of endometriosis were examined in 1,176,329 women aged between 16-60 years who continuously enrolled in the database.
  • The secondary analysis estimated the prevalence of CPP and dysmenorrhea during the study period.

Key Results: 

  • The average incidence of endometriosis is 24,3 per 10.000 person-years during this 10 years study period, with a significant decrease from 30,2 to 17,4 per 10.000 person-year in 2015.
  • This decline is independent of age, ethnicity, and race, diagnosis modality (surgery, imaging, clinical), or provider medical professionals.
  • The annual prevalence rate of chronic pelvic pain increased from 3.0 to 5,6%, but the frequency of dysmenorrhea remained unchanged over the study interval.

Lay Summary

To define the accurate incidence and prevalence estimates of endometriosis among nonselected cohorts in the USA, Christ et al. from the Departments of Obstetrics and Gynecology of the University of Washington, Seattle, planned a retrospective cohort study using the electronic KPWA database between 2006-2015.

All enrollees who were 16 to 60 years of age women comprised the study population, who were continuously enrolled at least 2 years before cohort entry, and had at least 1 encounter with the health utilization. 

During the 10-years study period, the overall incidence rate of endometriosis was 24,3% per 10.000 person-year. Analyzing the incidence rates annually, a decline from 30,2% per 10.000 in 2006 to 17,4% per 10.000 in 2015 was detected. Women in the 36-45 year-age group had the highest incidence rates of all other age groups but their values also tend to decline over a 10 year period. These declines in incidence over time were seen across all ages, races, and ethnicity, diagnostic modalities, and the diagnostic provider medical professional.

Chronic pelvic pain symptoms of patients almost doubled during this ten-year study period,  supporting the hypothesis that reduced endometriosis incidence rates may be the result of a relative increase in the percentage of patients with associated conditions.

"To clarify the reason for declining incidence rates in the US need additional research" concluded the authors, in this recently published paper in the "American Journal of Obstetrics and Gynecology".


Research Source:

incidence prevalence dysmenorrhea chronic pelvic pain diagnosis ethnicity diagnosis modality endometriosis.


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