The effects of surgery for endometriosis on pregnancy outcomes following in vitro fertilization and embryo transfer: a systematic review and meta-analysis.

PURPOSE: To review the literature about the effect of endometriosis on in vitro-fertilization and embryo-transfer (IVF-ET).

METHODS: A search in EMBASE, MEDLINE, ClinicalTrial.gov, reference lists from 2000 to 2013 was conducted. Inclusion criteria were: endometriosis confirmed with histologic examination, women undergoing IVF-ET, endometriosis treated or diagnosed by surgery. Women undergoing IVF-ET after surgical removal of endometriosic implants, or a surgical diagnosis of endometriosis without its removal, were compared to women without endometriosis. Main outcomes were clinical pregnancy and delivery rates.

RESULTS: Thirteen studies were selected, including 980 women with endometriosis and 5934 controls. Clinical pregnancy rate was lower in women with endometriosis than in controls (OR 0.65; 95 % CI 0.44-0.96), but delivery rate was similar (OR 1.17; 95 % CI 0.69-1.98). When surgery was operative, clinical pregnancy rate after IVF-ET was lower in endometriosis than controls (OR 0.54; 95 % CI 0.34-0.85), but delivery rate was similar (OR 1.12; 95 % CI 0.60-2.07). When surgery was diagnostic, clinical pregnancy (OR 1.15; 95 % CI 0.46-2.84) and delivery rates (OR 1.65; 95 % CI 0.36-7.45) did not differ between the groups. Site of endometriosis was not related to IVF-ET outcomes. Clinical pregnancy rates were similar between stage I-II and controls (OR 0.99; 95 % CI 0.63-1.56) but lower in stage III-IV than controls (OR 0.45; 95 % CI 0.29-0.70), whereas delivery rate was not associated with stage.

CONCLUSIONS: In the presence of endometriosis, the clinical pregnancy rate after IVF-ET is lower than in controls. The prognosis is better for mild endometriosis compared with more advanced stages. Even after surgical removal of endometriosis, IVF-ET results remain worse than in controls.