title: Minimal stimulation IVF with late follicular phase administration of the GnRH antagonist cetrorelix and concomitant substitution with recombinant FSH: a pilot study.
abstract: BACKGROUND
  The use of the natural cycle for IVF offers the advantage of a patient-friendly and low-risk protocol. Its effectiveness is limited, but may be improved by using a GnRH antagonist to prevent untimely LH surges.
  
  
  METHODS
  In this pilot study, minimal stimulation IVF with late follicular phase administration of the GnRH antagonist cetrorelix and simultaneous substitution with recombinant FSH was applied for a maximum of three cycles per patient. Main outcome measures were pregnancy rates per started cycle and cumulative pregnancy rates after three cycles.
  
  
  RESULTS
  A total of 50 patients completed 119 cycles (2.4 per patient). Fifty-two embryo transfers resulted in 17 ongoing pregnancies [14.3% per started cycle; 32.7% per embryo transfer; 95% confidence interval (CI) 7.9-20.7% and 19.7-45.7%, respectively]. One dizygotic twin pregnancy occurred after transfer of two embryos, the other pregnancies were singletons. The cumulative ongoing pregnancy rate after three cycles was 34% (95% CI 20.6-47.4%). Live birth rate was 32% per patient (95% CI 18.8-45.2%).
  
  
  CONCLUSIONS
  Pregnancy rates after IVF with minimal, late follicular phase stimulation are encouraging. Considering the low-risk and patient-friendly nature of this protocol, it may be a feasible alternative to IVF with ovarian hyperstimulation.
authors.affiliation: Section of Reproductive Medicine, Department of Obstetrics and Gynaecology, University Hospital Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands.
authors.forename: M J
authors.initials: MJ
authors.lastname: Pelinck
authors.forename: N E A
authors.initials: NE
authors.lastname: Vogel
authors.forename: A
authors.initials: A
authors.lastname: Hoek
authors.forename: E G J M
authors.initials: EG
authors.lastname: Arts
authors.forename: A H M
authors.initials: AH
authors.lastname: Simons
authors.forename: M J
authors.initials: MJ
authors.lastname: Heineman
mesh_terms: D000328:Adult; D004334:Drug Administration Schedule; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D005640:Follicle Stimulating Hormone / Q000627:therapeutic use*; D005498:Follicular Phase; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage* / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000627:therapeutic use; D006727:Hormone Antagonists / Q000008:administration & dosage* / Q000627:therapeutic use; D006801:Humans; D010062:Ovulation Induction / Q000379:methods*; D010865:Pilot Projects; D011247:Pregnancy; D018873:Pregnancy Rate; D011272:Pregnancy, Multiple; D011994:Recombinant Proteins / Q000627:therapeutic use; D014429:Twins, Dizygotic
chemical_list: D006727:Hormone Antagonists; D011994:Recombinant Proteins; D007987:Gonadotropin-Releasing Hormone; D005640:Follicle Stimulating Hormone; C062876:cetrorelix