title: Is the presence of a non-cleaved embryo on day 3 associated with poorer quality of the remaining embryos in the cohort?
abstract: OBJECTIVE
  Morphological evaluation is currently considered the single most important predictive measure for assessing embryo quality. The aim of this study was to investigate whether cycles with at least one non-cleaved embryo (i.e., a 1-cell embryo on day 3) have different outcomes compared with cycles in which all embryos had cleaved by day 3.
  
  
  METHODS
  All autologous IVF/ICSI cycles with a fresh day 3 transfer and without using a gestational carrier performed at our center between 1/1/2010 and 12/31/2011 were analyzed retrospectively. Those cycles with at least one non-cleaved embryo on day 3 were compared with all other autologous cycles that had 100% cleaved embryos performed during the study period.
  
  
  RESULTS
  Eight hundred and forty two cycles were included. Of them, 144 cycles comprised the non-cleaved group, and 698 cycles comprised the cleaved group. Cycles in the non-cleaved group had more oocytes retrieved (15.4 ± 7.1 vs. 12.5 ± 7.1, p < 0.001), more zygotes obtained (10.0 ± 5.3 vs. 7.9 ± 5.2, p = <0.001), but the embryos exhibited lower cleavage rates and higher rates of fragmentation and asymmetry compared with controls (p < 0.001). However, spontaneous abortion rates, ectopic pregnancies rates as well as delivery rates were similar between the two groups.
  
  
  CONCLUSIONS
  Our results show that the presence of a non-cleaved embryo on day 3 is associated with a more exuberant response to controlled ovarian stimulation as reflected by more oocytes retrieved. Despite the significant decrease in quality of the whole cohort in the non-cleaved group, implantation, delivery rates and number of embryos frozen were not adversely affected by the presence of a non-cleaved embryo.
authors.affiliation: Department of Obstetrics, Gynecology and Reproductive Biology, Brigham & Women's Hospital, Harvard Medical School, 75 Francis Street, ASB 1+3, Rm 082, Boston, MA, 02115, USA.
authors.forename: Ronit
authors.initials: R
authors.lastname: Machtinger
authors.forename: Charles L
authors.initials: CL
authors.lastname: Bormann
authors.forename: Elizabeth S
authors.initials: ES
authors.lastname: Ginsburg
authors.forename: Catherine
authors.initials: C
authors.lastname: Racowsky
mesh_terms: D000328:Adult; D004624:Embryo Transfer; D004622:Embryo, Mammalian / Q000166:cytology*; D047108:Embryonic Development; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D009865:Oocytes / Q000166:cytology*; D010062:Ovulation Induction; D011247:Pregnancy; D018873:Pregnancy Rate; D011786:Quality Control; D012189:Retrospective Studies; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods*