title: Impact of endometriosis and its staging on assisted reproduction outcome: systematic review and meta-analysis.
abstract: OBJECTIVE
  To evaluate whether the presence or severity of endometriosis affects the outcome of assisted reproductive techniques (ART).
  
  
  METHODS
  In this systematic review, all studies comparing the outcome of ART in women with and those without endometriosis, or at different stages of the disease, were considered eligible. We used either risk ratio (RR) or mean difference (MD) and their 95%CIs for comparisons. The primary outcome was live birth; the secondary outcome was clinical pregnancy. Miscarriage and the number of oocytes retrieved were examined as additional outcomes.
  
  
  RESULTS
  We included 92 studies in the review and 78 in the meta-analysis: 20,167 women with endometriosis were compared with 121,931 women without endometriosis, and 1703 women with Stage-III/IV endometriosis were compared with 2227 women with Stage-I/II endometriosis. The following results were observed for the comparison of women with endometriosis vs women without endometriosis: live birth, RR = 0.99 (95%CI, 0.92-1.06); clinical pregnancy, RR = 0.95 (95%CI, 0.89-1.02); miscarriage, RR = 1.31 (95%CI, 1.07-1.59); number of oocytes retrieved, MD = -1.56 (95%CI, -2.05 to -1.08). The following results were observed for the comparison of women with Stage-III/IV vs Stage-I/II endometriosis: live birth, RR = 0.94 (95%CI, 0.80-1.11); clinical pregnancy, RR = 0.90 (95%CI, 0.82-1.00); miscarriage, RR = 0.99 (95%CI, 0.73-1.36); number of oocytes retrieved, MD = -1.03 (95%CI, -1.67 to -0.39).
  
  
  CONCLUSIONS
  Women with endometriosis undergoing ART have practically the same chance of achieving clinical pregnancy and live birth as do women with other causes of infertility. No relevant difference was observed in the chance of achieving clinical pregnancy and live birth following ART when comparing Stage-III/IV with Stage-I/II endometriosis. The quality of the evidence for the additional examined outcomes was very low, not allowing meaningful conclusions to be drawn.
authors.affiliation: Department of Obstetrics and Gynecology, Medical School of Ribeirao Preto, University of Sao Paulo (FMRP-USP), Ribeirao Preto, Brazil.
authors.forename: M A P
authors.initials: MA
authors.lastname: Barbosa
authors.forename: D M
authors.initials: DM
authors.lastname: Teixeira
authors.forename: P A A S
authors.initials: PA
authors.lastname: Navarro
authors.forename: R A
authors.initials: RA
authors.lastname: Ferriani
authors.forename: C O
authors.initials: CO
authors.lastname: Nastri
authors.forename: W P
authors.initials: WP
authors.lastname: Martins
mesh_terms: D000022:Abortion, Spontaneous / Q000453:epidemiology / Q000209:etiology*; D000328:Adult; D004715:Endometriosis / Q000150:complications* / Q000453:epidemiology; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D050498:Live Birth; D054315:Oocyte Retrieval; D011247:Pregnancy; D011256:Pregnancy Outcome; D018873:Pregnancy Rate; D027724:Reproductive Techniques, Assisted / Q000706:statistics & numerical data; D012720:Severity of Illness Index
keywords: assisted reproductive techniques; embryo transfer; endometriosis; meta-analysis; review