title: Supraphysiological estradiol levels do not affect oocyte and embryo quality in oocyte donation cycles.
abstract: BACKGROUND
  The study aim was to determine whether supraphysiological estradiol (E(2)) levels reduce oocyte/embryo quality in oocyte donation cycles.
  
  
  METHODS
  A retrospective analysis of 330 consecutive fresh oocyte donation cycles was performed in an assisted reproductive treatment programme between January 1996 and December 2000. Throughout the study period, oocyte donors and recipients followed a standard synchronization regimen that did not vary. A serum E(2) level (peak E(2)) was obtained from all oocyte donors on the morning of HCG administration. Peak E(2) values were grouped by 33rd percentile (group I, <1500 pg/ml; group II, 1500-3000 pg/ml; and group III, >3000 pg/ml). All embryo transfers were performed on day 3 after oocyte recovery.
  
  
  RESULTS
  Comparisons between groups revealed no significant differences in the quality of oocytes retrieved, and in fertilization rates. Higher peak E(2) levels were directly correlated with a greater number of oocytes retrieved, embryos available for transfer and cryopreservation, and higher average embryo quality scores (P < 0.005). Compared with group I, group III had significantly higher embryo implantation rates (P < 0.05).
  
  
  CONCLUSIONS
  Sustained supraphysiological E(2) levels do not adversely affect the quality of developing oocytes and embryos. On the contrary, elevated E(2) levels are associated with a larger number of oocytes and embryos and high-grade embryos for transfer/cryopreservation and, consequently, improved implantation rates.
authors.affiliation: Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology, College of Physicians & Surgeons, Columbia University, New York, New York 10032, USA.
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Peña
authors.forename: Peter L
authors.initials: PL
authors.lastname: Chang
authors.forename: Lai-King
authors.initials: LK
authors.lastname: Chan
authors.forename: Khaled
authors.initials: K
authors.lastname: Zeitoun
authors.forename: Melvin H
authors.initials: MH
authors.lastname: Thornton
authors.forename: Mark V
authors.initials: MV
authors.lastname: Sauer
mesh_terms: D000328:Adult; D006063:Chorionic Gonadotropin / Q000008:administration & dosage; D015925:Cryopreservation; D010064:Embryo Implantation; D004624:Embryo Transfer; D004622:Embryo, Mammalian / Q000502:physiology*; D004958:Estradiol / Q000097:blood*; D005260:Female; D005307:Fertilization in Vitro; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D016015:Logistic Models; D008297:Male; D018587:Oocyte Donation; D009865:Oocytes / Q000502:physiology*; D012189:Retrospective Studies; D020554:Sperm Injections, Intracytoplasmic
chemical_list: D006063:Chorionic Gonadotropin; D004958:Estradiol; D005640:Follicle Stimulating Hormone