title: In vitro fertilization in unstimulated cycles: the University of Southern California experience.
abstract: OBJECTIVE
  To describe the clinical experience of our center with in vitro fertilization (IVF) in unstimulated cycles and to provide a comparison to stimulated cycles.
  
  
  METHODS
  Spontaneous ovulatory cycles were triggered with human chorionic gonadotropin in the midcycle, and 78 aspirations for IVF were performed, with the remainder of the IVF cycle proceeding in a standard manner.
  
  
  METHODS
  The IVF program of the University of Southern California and the California Medical Center, Los Angeles, California.
  
  
  METHODS
  Spontaneously ovulatory women (n = 46) with predominantly pelvic factor as their principal cause of infertility, under the age of 40, and no male factor.
  
  
  METHODS
  Human chorionic gonadotropin administration in midcycle, follicle aspiration, IVF, and embryo transfer.
  
  
  METHODS
  Embryo implantation and pregnancy.
  
  
  RESULTS
  Seventy-eight follicle aspirations resulted in 11 clinical (14%) and 9 ongoing (12%) pregnancies. The per embryo implantation rate was 13% clinical and 11% ongoing. There was no decrease in per cycle pregnancy rates (PRs) for up to three unstimulated cycles.
  
  
  CONCLUSIONS
  Unstimulated IVF is a viable alternative to stimulated cycles with PRs approximately one half those of stimulated cycles. It is reasonable to offer patients up to three cycles of unstimulated IVF without expecting a decrease in PRs.
authors.affiliation: University of Southern California School of Medicine, Los Angeles.
authors.forename: R J
authors.initials: RJ
authors.lastname: Paulson
authors.forename: M V
authors.initials: MV
authors.lastname: Sauer
authors.forename: M M
authors.initials: MM
authors.lastname: Francis
authors.forename: T M
authors.initials: TM
authors.lastname: Macaso
authors.forename: R A
authors.initials: RA
authors.lastname: Lobo
mesh_terms: D006063:Chorionic Gonadotropin / Q000494:pharmacology; D010064:Embryo Implantation; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D015993:Life Tables; D008597:Menstrual Cycle; D011247:Pregnancy; D013268:Stimulation, Chemical
chemical_list: D006063:Chorionic Gonadotropin