Systematic review and meta-analysis regarding the association of endometriosis and preeclampsia in women conceiving spontaneously or through assisted reproductive technology

Objective: To investigate the association between endometriosis and preeclampsia and/or its severe forms (eclampsia and/or the hemolysis, elevated liver enzymes and low platelet count [HELLP] syndrome) in pregnancies conceived either spontaneously or by assisted reproductive technology (ART). Design and Methods: Systematic review and meta-analysis of observational studies. Search in PubMed-Medline, Scopus, Web of Science, Cochrane Library, Clinicaltrials.gov, the UK Clinical Trials Gateway, and the Australian New Zealand Clinical Trials Registry was conducted from inception through 21 June 2017, without language restrictions. Primary outcome was preeclampsia and/or its severe forms (eclampsia and/or HELLP syndrome) in pregnant women. Random-effects models were used for meta-analyses. Endometriosis effect was estimated as odds ratio (OR) with 95% confidence interval (CI). Results: A total of 9 cohort and 4 case-control studies were eligible for data analysis, including 39,816 pregnancies with endometriosis and 2,831,065 without. Women with endometriosis diagnosed through biopsy did not have a higher preeclampsia, eclampsia and HELLP syndrome risk as compared to those without (OR 1.01, 95% CI 0.56–1.82); this was found the same even if endometriosis was diagnosed using other procedures (OR 1.15, 95% CI 0.94–1.40). Preeclampsia, eclampsia and HELLP syndrome risk was also not increased in women with endometriosis conceiving spontaneously (OR 1.21; 95% CI 0.94–1.56) or through ART (OR 0.74; 95% CI 0.41–1.35). Conclusion: This meta-analysis evidences that endometriosis was not associated to a higher risk of preeclampsia and/or its severe forms in pregnancies either conceived spontaneously or through ART.