title: Intracytoplasmic sperm injection (ICSI) in unexplained and stage I endometriosis-associated infertility after fertilization failure with in vitro fertilization (IVF).
abstract: OBJECTIVE
  To investigate possible differences between unexplained and stage I endometriosis-associated infertility in ICSI cycles conducted after low fertilization (<20%) in preceding IVF cycles with normal semen parameters.
  
  
  METHODS
  Retrospective cohort study consisting of patients with unexplained (n=48) and stage I endometriosis-associated infertility (n=43) with a minimum of one IVF cycle with <20% fertilized oocytes and normal semen quality, treated with ICSI from January 1997 to January 2006. Age matched male factor infertility patients (n=91) were used as controls.
  
  
  RESULTS
  Diploid fertilization rate was significantly lower in the stage I endometriosis-associated infertility group compared to the unexplained infertility group. Score of the transferred embryos, implantation rate, pregnancy rate and outcome were similar in the two groups.
  
  
  CONCLUSIONS
  ICSI appears to be an efficient treatment option after fertilization failure with IVF in unexplained and stage I endometriosis-associated infertility.
authors.affiliation: Department of Obstetrics and Gynaecology, Rikshospitalet-Radiumhospitalet Medical Center, Sognsvannsveien 20, 0027, Oslo, Norway. anne.omland@rikshospitalet.no
authors.forename: Anne K
authors.initials: AK
authors.lastname: Omland
authors.forename: Sverre
authors.initials: S
authors.lastname: Bjercke
authors.forename: Gudvor
authors.initials: G
authors.lastname: Ertzeid
authors.forename: Peter
authors.initials: P
authors.lastname: Fedorcsák
authors.forename: Nan B
authors.initials: NB
authors.lastname: Oldereid
authors.forename: Ritsa
authors.initials: R
authors.lastname: Storeng
authors.forename: Thomas
authors.initials: T
authors.lastname: Abyholm
authors.forename: Tom
authors.initials: T
authors.lastname: Tanbo
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D015331:Cohort Studies; D004715:Endometriosis / Q000150:complications*; D005069:Evaluation Studies as Topic; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007246:Infertility / Q000209:etiology* / Q000628:therapy*; D011247:Pregnancy; D018873:Pregnancy Rate; D012189:Retrospective Studies; D020554:Sperm Injections, Intracytoplasmic; D016896:Treatment Outcome