title: Outcome of frozen embryo replacement cycles following elective cryopreservation of all embryos in women at risk of developing ovarian hyperstimulation syndrome.
abstract: OBJECTIVE
  Our aim was to compare the outcome in subsequent frozen embryo replacement cycles in four groups of patients who had elective cryopreservation of all their embryos because they were considered to be at increased risk of developing severe ovarian hyperstimulation syndrome.
  
  
  METHODS
  Sixty-two (91%) of 68 IVF cycles (68 patients) in which elective cryopreservation of all embryos was performed were analyzed. All patients continued on the GnRH agonist, buserelin, after oocyte recovery until the onset of vaginal bleeding. Frozen embryo replacement occurred in a hormone replacement cycle that started either on day 3 of the withdrawal bleed (group I; N = 15) or after serum estradiol levels had fallen to < 100 pmol/L (group II; N = 16). The other patients commenced a frozen embryo replacement cycle several months later in either a hormone replacement (group III; N = 15) or a natural (group IV; N = 16) cycle.
  
  
  RESULTS
  Two patients developed severe ovarian hyperstimulation syndrome. There were no significant differences among the four groups regarding demographic variables, the dose of hMG used, and the clinical outcome. There was a higher but not significantly different clinical pregnancy rate in group I (26.7%), compared to group II (12.5%), group III (13.3%), and group IV (18.8%).
  
  
  CONCLUSIONS
  Several options exist for the timing and protocol used for frozen embryo replacement in patients who had elective cryopreservation for the prevention of ovarian hyperstimulation syndrome, none of which was found to be clearly superior in this observational report.
authors.affiliation: London Women's Clinic, UK.
authors.forename: A O
authors.initials: AO
authors.lastname: Awonuga
authors.forename: N
authors.initials: N
authors.lastname: Dean
authors.forename: J
authors.initials: J
authors.lastname: Zaidi
authors.forename: R U
authors.initials: RU
authors.lastname: Pittrof
authors.forename: J S
authors.initials: JS
authors.lastname: Bekir
authors.forename: S L
authors.initials: SL
authors.lastname: Tan
mesh_terms: D000328:Adult; D015925:Cryopreservation; D004624:Embryo Transfer; D004958:Estradiol / Q000097:blood; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D016471:Ovarian Hyperstimulation Syndrome; D011247:Pregnancy; D016896:Treatment Outcome
chemical_list: D004958:Estradiol