title: Impact of a cryopreservation program on the multiple pregnancy rate associated with assisted reproductive technologies.
abstract: OBJECTIVE
  To determine the impact of a cryopreservation program on pregnancy rates and multiple-pregnancy rates in ART cycles.
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  University teaching hospital.
  
  
  METHODS
  Women who underwent stimulation for in vitro fertilization at the Jones Institute for Reproductive Medicine between October 1987 and June 1999.
  
  
  METHODS
  Analysis of pregnancy and multiple-pregnancy rates based on the number of embryos transferred.
  
  
  METHODS
  Implantation; pregnancy and multiple-pregnancy rates.
  
  
  RESULTS
  Pregnancy rates per transfer increased from 9% when one embryo was transferred to 20% with two embryos, 35% with three embryos, 40% with four embryos, and 41% with five embryos. The rate of twin pregnancies increased to 21% with two embryos, 23% with three embryos, 21% with four embryos, and 22% with five embryos. The triplet pregnancy rates were 8% with three embryos, 9% with four embryos, and 2% with five embryos. A theoretical model limiting the number of embryos transferred to two with cryopreservation and subsequent transfer yields a cumulative pregnancy rate of 77%, a twin rate of less than 20%, and no triplet or higher-order pregnancies.
  
  
  CONCLUSIONS
  The use of a cryopreservation program can help maximize pregnancy rates while minimizing multiple-pregnancy rates. Cryopreservation should be considered in all assisted reproductive technology cycles.
authors.affiliation: Department of Obstetrics and Gynecology, The Jones Institute for Reproductive Medicine, Eastern Virginia Medical School, Norfolk, Virginia 23507, USA. schnorja@evms.edu
authors.forename: J A
authors.initials: JA
authors.lastname: Schnorr
authors.forename: M J
authors.initials: MJ
authors.lastname: Doviak
authors.forename: S J
authors.initials: SJ
authors.lastname: Muasher
authors.forename: H W
authors.initials: HW
authors.lastname: Jones
mesh_terms: D000328:Adult; D015925:Cryopreservation / Q000706:statistics & numerical data*; D004624:Embryo Transfer; D004958:Estradiol / Q000097:blood; D005260:Female; D005300:Fertility Agents, Female / Q000627:therapeutic use; D005640:Follicle Stimulating Hormone / Q000097:blood / Q000627:therapeutic use; D006801:Humans; D007247:Infertility, Female / Q000188:drug therapy; D007986:Luteinizing Hormone / Q000097:blood / Q000627:therapeutic use; D008596:Menotropins / Q000627:therapeutic use; D008962:Models, Theoretical; D011247:Pregnancy; D018873:Pregnancy Rate; D011272:Pregnancy, Multiple / Q000706:statistics & numerical data*; D011994:Recombinant Proteins / Q000627:therapeutic use; D012099:Reproductive Techniques / Q000706:statistics & numerical data*; D012189:Retrospective Studies
chemical_list: D005300:Fertility Agents, Female; D011994:Recombinant Proteins; D004958:Estradiol; D008596:Menotropins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone