title: Effect of a programmed short-term stimulation protocol on the replacement of cryopreserved embryos.
abstract: OBJECTIVE
  Through problems in the management of embryo thawings and transfers, we investigated in a comparative study the use of the natural cycle and of a programmed short-term stimulation protocol as preparation method for the replacement of cryopreserved embryos. To date, 117 embryos have been thawed, and 60 (51%) survived with > or = 50% intact blastomeres.
  
  
  METHODS
  In 31 cases, replacement of the frozen-thawed embryos was planned in the natural cycle (group A) and in nine cases in the stimulated cycle (group B). In group A, 16 replacements could be performed (cancellation rate 48%). Six transfers took place on weekends (37%). Two clinical pregnancies could be established (13% per replacement). In group B, there were no canceled cycles (p < 0.025). All thawings and transfers could be conducted between Monday and Friday. In one case, the single one frozen embryo was degenerated after thawing.
  
  
  RESULTS
  Thus, eight replacements could be performed which resulted in three clinical pregnancies (38% per replacement, n.s.) and one biochemical pregnancy.
  
  
  CONCLUSIONS
  Based on our results, we conclude that a programmed short-term protocol not only provides viable embryos with a good cryopreservation potential, but it is also a reliable preparation method for the replacement of frozen-thawed embryos.
authors.affiliation: Department of Gynecology and Obstetrics, University Hospital, Zurich, Switzerland.
authors.forename: B
authors.initials: B
authors.lastname: Imthurn
authors.forename: E
authors.initials: E
authors.lastname: Macas
authors.forename: M
authors.initials: M
authors.lastname: Rosselli
authors.forename: P J
authors.initials: PJ
authors.lastname: Keller
mesh_terms: D000328:Adult; D002985:Clinical Protocols; D015925:Cryopreservation; D004624:Embryo Transfer / Q000379:methods*; D004622:Embryo, Mammalian; D005260:Female; D005307:Fertilization in Vitro; D015181:Gamete Intrafallopian Transfer; D006801:Humans; D008597:Menstrual Cycle / Q000502:physiology*; D009640:Norethindrone / Q000031:analogs & derivatives*; D000077563:Norethindrone Acetate; D010062:Ovulation Induction / Q000379:methods*
chemical_list: D000077563:Norethindrone Acetate; D009640:Norethindrone