title: In vitro fertilization-intracytoplasmic sperm injection split: an insemination method to prevent fertilization failure.
abstract: OBJECTIVE
  To determine whether the performance of intracytoplasmic sperm injection (ICSI) in cases of unexplained infertility and of borderline semen parameters can prevent fertilization failure.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  Hospital-based assisted reproductive technology program.
  
  
  METHODS
  Sixty couples with unexplained infertility (group 1) and 50 couples with borderline semen (group 2).
  
  
  METHODS
  Conventional IVF and ICSI were performed on sibling oocyte cumulus complexes.
  
  
  METHODS
  Rate of fertilization according to patient diagnosis.
  
  
  RESULTS
  The fertilization rate per oocyte cumulus complex in couples with unexplained infertility (group 1) was significantly higher with ICSI (65.3%) compared with IVF insemination (48.1%). Fertilization rates per OCC in couples with borderline semen (group 2) were not significantly different between ICSI (58.1%) and IVF (56.7%). In group 1, failure of fertilization after IVF insemination occurred in 10 of the 60 couples (16.7%) and in none with ICSI. In group 2, 2 of 50 couples (4.0%) failed fertilization by IVF, and 1 (2.0%) failed with ICSI. No couple in group 2 failed both IVF insemination and ICSI.
  
  
  CONCLUSIONS
  In couples with unexplained infertility, a higher fertilization rate was achieved through ICSI compared with conventional IVF. No such benefit could be demonstrated for couples with borderline semen parameters. The use of ICSI rescued 12 of 110 cycles (10.9%) where IVF failed. Adoption of the ICSI-IVF insemination split in cases of unexplained infertility may help eliminate fertilization failures.
authors.affiliation: Center for Human Reproduction, Ambulatory Surgery, North Shore University Hospital-New York University School of Medicine, 300 Community Drive, Manhasset, NY 11030, USA. ahershlag@nshs.org
authors.forename: Avner
authors.initials: A
authors.lastname: Hershlag
authors.forename: Terry
authors.initials: T
authors.lastname: Paine
authors.forename: Georgina
authors.initials: G
authors.lastname: Kvapil
authors.forename: Huailiang
authors.initials: H
authors.lastname: Feng
authors.forename: Barbara
authors.initials: B
authors.lastname: Napolitano
mesh_terms: D015331:Cohort Studies; D005260:Female; D005306:Fertilization / Q000502:physiology*; D006801:Humans; D007248:Infertility, Male / Q000628:therapy*; D008297:Male; D009865:Oocytes / Q000502:physiology; D011247:Pregnancy; D011446:Prospective Studies; D012661:Semen / Q000502:physiology*; D013076:Sperm Count; D020554:Sperm Injections, Intracytoplasmic; D013081:Sperm Motility / Q000502:physiology