Design: Systematic review and meta-analysis

Setting: Translational, preclinical mouse model

Patients or Participants: Articles using an immunocompetent mouse model that included abdominal endometriosis and reported at least one quantifiable lesion measurement with associated standard deviations or standard errors.

Interventions: Each article was evaluated for inclusion, data were extracted, and risk of bias and quality of articles were determined by 2 or more independent reviewers.

Measurements and Main Results: The search strategy identified 124 articles (total number of mice, n=3056) for inclusion. There were approximately 26 total (SD=21; median=20) mice on average per article in the suture sub-group and approximately 25 total (SD=26; median=17) mice per article on average in the injection sub-group. The average mice per experiment per article had approximately 11 mice (SD=6) in the injection sub-group and approximately 9 mice (SD=5) in the suture sub-group (p=.022981). Meta-regression showed recipient exogenous supplemental hormones (p= 0.01856) and BALB/c strain (p=0.036) affected lesion weight, autologous grafts (p=0.004) affected lesion volume, syngeneic grafts (p=0.008) affected lesion area, myometrium with endometrium (p=<0.001) affected lesion diameter, and the BALB/c strain (p=0.032) and recipient exogenous supplemental hormones (p=0.004) affected the number of lesions.

Conclusion: The degree of heterogeneity, risk of bias, and low or very low quality of evidence emphasizes the need for a call to action. Model standardization, agreed upon by the research community, would improve reproducibility and allow for evidenced-based translational outcomes, especially in the setting of pre-clinical endometriosis studies.