title: Embryo cryopreservation rescues cycles with premature luteinization.
abstract: OBJECTIVE
  To determine whether embryo cryopreservation in cycles with elevated preovulatory P followed by thaw, extended culture, and transfer results in greater ongoing pregnancy rates than fresh blastocyst transfer.
  
  
  METHODS
  Retrospective matched cohort study.
  
  
  METHODS
  Private fertility center.
  
  
  METHODS
  The study group consisted of 118 consecutive thaws of bipronucleate (2PN) oocytes derived from autologous cycles with elevated preovulatory P, resulting in 95 blastocyst transfers. The control group was selected by matching on the number of 2PN oocytes and patient age and consisted of 118 fresh cycles with elevated preovulatory P, including 108 fresh autologous blastocyst transfers. All patients were <41 years old at the time of stimulation.
  
  
  METHODS
  None.
  
  
  METHODS
  Implantation and ongoing pregnancy rates.
  
  
  RESULTS
  The study group had significantly fewer blastocysts per 2PN oocyte than the control group (19.7% vs. 36.8%, respectively) and a significantly greater cancellation rate (19.5% vs. 8.5%, respectively). However, the ongoing pregnancy rate per cycle was significantly higher in the study group than in the control group (56.8% vs. 32.2%, respectively), resulting from greater rates of implantation (56.8% vs. 26.9%, respectively) and of ongoing pregnancy per transfer (70.5% vs. 35.2%, respectively).
  
  
  CONCLUSIONS
  In cycles with elevated preovulatory P, the probabilities of implantation and ongoing pregnancy are increased if all 2PN oocytes are cryopreserved and subsequently thawed and cultured to the blastocyst stage before transfer.
authors.affiliation: Fertility Center of Las Vegas, University of Nevada School of Medicine, 8851 West Sahara Avenue, Las Vegas, Nevada 89117, USA. bsshapiro@aol.com
authors.forename: Bruce S
authors.initials: BS
authors.lastname: Shapiro
authors.forename: Said T
authors.initials: ST
authors.lastname: Daneshmand
authors.forename: Forest C
authors.initials: FC
authors.lastname: Garner
authors.forename: Martha
authors.initials: M
authors.lastname: Aguirre
authors.forename: Cynthia
authors.initials: C
authors.lastname: Hudson
authors.forename: Shyni
authors.initials: S
authors.lastname: Thomas
mesh_terms: D000328:Adult; D018929:Cell Culture Techniques; D002467:Cell Nucleus / Q000502:physiology; D015331:Cohort Studies; D015925:Cryopreservation / Q000379:methods*; D010064:Embryo Implantation / Q000502:physiology*; D004622:Embryo, Mammalian / Q000166:cytology* / Q000502:physiology*; D004717:Endometrium / Q000473:pathology; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods; D006801:Humans; D007315:Insemination, Artificial; D034461:Luteinization / Q000502:physiology*; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D054315:Oocyte Retrieval / Q000379:methods; D009865:Oocytes / Q000166:cytology / Q000502:physiology*; D011247:Pregnancy; D011374:Progesterone / Q000097:blood; D012189:Retrospective Studies
chemical_list: D011374:Progesterone; D007986:Luteinizing Hormone