title: Intracytoplasmic sperm injection overcomes previous fertilization failure with conventional in vitro fertilization.
abstract: OBJECTIVE
  To evaluate the outcome of intracytoplasmic sperm injection (ICSI) in patients with previous idiopathic fertilization failure (< or =20% fertilization rate) after conventional IVF.
  
  
  METHODS
  Retrospective analysis.
  
  
  METHODS
  IVF program at a university medical center.
  
  
  METHODS
  Twenty-five patients who underwent 38 ICSI cycles after experiencing unexplained fertilization failure with conventional IVF (group A) and 87 patients who underwent 118 ICSI cycles for male factor indications during the same period (group B).
  
  
  METHODS
  Intracytoplasmic sperm injection was performed in a subsequent cycle after fertilization failure with conventional IVF.
  
  
  METHODS
  Outcomes of IVF were compared between groups A and B.
  
  
  RESULTS
  Fertilization was achieved with ICSI in all patients with previous fertilization failure. The mean (+/- SD) fertilization rate (68%+/-21% vs. 64%+/-22%), implantation rate per embryo (22.6% vs. 20%), and delivery rate per cycle (47.3% vs. 49.1%) did not differ significantly between groups A and B. Overall, 72% of patients with previous unexplained fertilization failure had a successful pregnancy after ICSI.
  
  
  CONCLUSIONS
  Intracytoplasmic sperm injection can overcome unexplained fertilization failure caused by a potentially occult gamete abnormality, with the same fertilization, implantation, and pregnancy rates as are seen in patients with abnormal sperm parameters.
authors.affiliation: The Center for Advanced Reproductive Services, Department of Obstetrics and Gynecology, University of Connecticut School of Medicine, Farmington 06030-6224, USA. benadiva@up.uchc.edu
authors.forename: C A
authors.initials: CA
authors.lastname: Benadiva
authors.forename: J
authors.initials: J
authors.lastname: Nulsen
authors.forename: L
authors.initials: L
authors.lastname: Siano
authors.forename: J
authors.initials: J
authors.lastname: Jennings
authors.forename: H B
authors.initials: HB
authors.lastname: Givargis
authors.forename: D
authors.initials: D
authors.lastname: Maier
mesh_terms: D000328:Adult; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008297:Male; D010062:Ovulation Induction / Q000379:methods; D011247:Pregnancy; D018873:Pregnancy Rate; D019233:Retreatment; D012189:Retrospective Studies; D020554:Sperm Injections, Intracytoplasmic; D013268:Stimulation, Chemical; D017211:Treatment Failure