title: Live births resulting from 0PN-derived embryos in conventional IVF cycles.
abstract: OBJECTIVE
  The aim of this study was to (1) investigate the incidence of embryos derived from "unfertilized oocytes" i.e., oocytes not displaying pronuclei (0PN) at the time of the fertilization check and (2) determine the clinical pregnancy rates when transferring 0PN-derived embryos.
  
  
  METHODS
  In this retrospective study, 4424 IVF-ET cycles were reviewed.
  
  
  RESULTS
  In total, 11.3% (4966/43,949) 0PN-derived embryos were observed. It was found that female age, number of oocytes, and the top-quality embryo rate were significantly correlated with 0PN-derived embryo occurrence. The source of embryos transferred did not impact significantly on clinical pregnancy and live-birth rates. Of the 183 cycles included in this study where 275 0PN-derived embryos were transferred in total, only 0PN-derived embryos were available in 70 of those cycles. It was noteworthy that 13 healthy infants resulted from 0PN-derived embryos with an implantation rate of 17.0%.
  
  
  CONCLUSIONS
  These results indicate that the traditional method of excluding embryos because of those oocytes originally lacking any sign of a pronucleus at the fertilization check should be re-considered as transferring 0PN-derived embryos with subsequent expected developmental performance may be considered as an option for those patients where no other embryos are available.
authors.affiliation: Reproductive Medicine Center, The third affiliated hospital of Zhengzhou University, Zheng Zhou, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.affiliation: Reproductive Medicine Center, The third affiliated hospital of Zhengzhou University, Zheng Zhou, China.
authors.forename: Xing Ling
authors.initials: XL
authors.lastname: Wang
authors.affiliation: Cork Fertility Centre, Fernhurst House, College Road, Cork, Ireland.
authors.forename: Xiao
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Reproductive Medicine Center, The third affiliated hospital of Zhengzhou University, Zheng Zhou, China.
authors.forename: Chun Yan
authors.initials: CY
authors.lastname: Shen
authors.affiliation: Reproductive Medicine Center, The third affiliated hospital of Zhengzhou University, Zheng Zhou, China. zhangzhanivf@hotmail.com.
authors.forename: Zhan
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D000328:Adult; D002467:Cell Nucleus / Q000502:physiology; D004624:Embryo Transfer / Q000379:methods; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D050498:Live Birth / Q000453:epidemiology; D008297:Male; D008423:Maternal Age; D009865:Oocytes / Q000473:pathology / Q000502:physiology*; D011247:Pregnancy; D018873:Pregnancy Rate; D012189:Retrospective Studies
keywords: 0PN; Abnormal fertilization; Implantation; Pregnancy; Pronucleus