title: Prediction of multiple pregnancies by the number of  early cleaving embryos.
abstract: OBJECTIVE
  The aim of the present study was to investigate the number of early cleaving embryos as an effective predictor for multiple pregnancies in human in vitro fertilization (IVF).
  
  
  METHODS
  The study analyzed early cleavage (EC) in 190 cycles of IVF. The EC of embryos to the two-cell stage was assessed at two time points, namely 25 and 27 h after insemination. Embryos that had cleaved at each time point were designated EC-1 and EC-2, respectively, whereas other embryos were designated as non-EC (NEC). The number of cycles with EC-1 embryos was not included in the results for the EC-2 group.
  
  
  RESULTS
  Clinical pregnancy rates were significantly higher in the EC-1 group compared with the EC-2 and NEC groups (58.2%, 31.8% and 22.9%, respectively; P < 0.05). The pregnancy outcome was positively related to the number of EC-1 embryos. Multiple pregnancy rates were significantly increased up to 41.4% when the number of EC-1 embryos was two or more.
  
  
  CONCLUSIONS
  The results confirm that 25 h after insemination is a more effective critical time point for the selection of EC embryos and that the number of EC embryos could be a useful parameter for the prediction of multiple pregnancies.
authors.affiliation: Department of Obstetrics and Gynecology, Pusan National University College of Medicine; Medical Research Institute, Pusan National University, Busan, Korea.
authors.forename: Yong-Jin
authors.initials: YJ
authors.lastname: Na
authors.forename: Jung-Pyo
authors.initials: JP
authors.lastname: Kim
authors.forename: Bo-Sun
authors.initials: BS
authors.lastname: Joo
authors.forename: Dong-Hyung
authors.initials: DH
authors.lastname: Lee
authors.forename: Kyu-Sup
authors.initials: KS
authors.lastname: Lee
mesh_terms: D000328:Adult; D002970:Cleavage Stage, Ovum; D046149:Embryo Culture Techniques; D004624:Embryo Transfer; D047108:Embryonic Development; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D011272:Pregnancy, Multiple