title: [Clinical analysis of intracytoplasmic sperm injection in patients with previous fertilization failure after conventional IVF].
abstract: OBJECTIVE
  To analyze the clinical outcome of intracytoplasmic sperm injection (ICSI) in patients with previous fertilization failure after conventional IVF.
  
  
  METHODS
  Data from 20 ICSI cases (22 ICSI cycles) with previous complete failure of fertilization or with fertilization rate < or = 20% between January 2002 and December 2004 were retrospectively analyzed. The control group consisted of 100 consecutive ICSI cycles for male factor infertility in the same period.
  
  
  RESULTS
  The fertilization rate dramatically increased from 5.4% after conventional IVF to 76.9% after ICSI treatment (chi-squared = 264.66, P < 0.001). However, the fertilization rate in the subgroup with previous low fertilization was significantly lower than those in the control and in the subgroup without previous fertilization (67.9% vs 77.5%, 67.9% vs 84.2%). Compared with the control group, the subgroup without previous fertilization had a higher pregnancy rate and implantation rate, but only the difference in the implantation rate was statistically significant (40.5% vs 18.9%).
  
  
  CONCLUSIONS
  ICSI can overcome previous fertilization failure with conventional in vitro fertilization and thus improve the clinical outcome.
authors.affiliation: Reproductive Medical Center, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, 510080, China. xuyanwen@pub.guangzhou.gd.cn
authors.forename: Yan-wen
authors.initials: YW
authors.lastname: Xu
authors.forename: Can-quan
authors.initials: CQ
authors.lastname: Zhou
authors.forename: Cong
authors.initials: C
authors.lastname: Fang
authors.forename: Min-fang
authors.initials: MF
authors.lastname: Zhang
authors.forename: Ming-fen
authors.initials: MF
authors.lastname: Deng
authors.forename: Xiu-bing
authors.initials: XB
authors.lastname: Zhang
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007246:Infertility / Q000628:therapy*; D008297:Male; D011247:Pregnancy; D011256:Pregnancy Outcome; D012189:Retrospective Studies; D020554:Sperm Injections, Intracytoplasmic; D017211:Treatment Failure