title: Extended letrozole regimen versus clomiphene citrate for superovulation in patients with unexplained infertility undergoing intrauterine insemination: a randomized controlled trial.
abstract: BACKGROUND
  The aim of this randomized controlled trial was to compare the efficacy of extended letrozole regimen with clomiphene citrate in women with unexplained infertility undergoing superovulation and intrauterine insemination (IUI).
  
  
  METHODS
  Two hundred and fourteen patients with unexplained infertility were randomized into two equal groups using computer generated list and were treated by either letrozole 2.5 mg/day from cycle day 1 to 9 (extended letrozole group, 211 cycles) or clomiphene citrate 100 mg/day from cycle day 3 to 7 (clomiphene citrate group,210 cycles). Intrauterine insemination was performed 36 to 40 hours after HCG administration.
  
  
  RESULTS
  Both groups were comparable with regard to number of mature follicles (2.24 +/- 0.80 Vs 2.13 +/- 0.76) and the day of HCG administration. Serum estradiol was significantly greater in clomiphene citrate group (356 +/- 151 Vs 822 +/- 302 pg/ml, P = < 0.001) and the endometrial thickness was significantly greater in extended letrozole group (9.10 +/- 1.84 Vs 8.18 +/- 1.93 mm, P = < 0.001).The pregnancy rate per cycle and cumulative pregnancy rate were significantly greater in extended letrozole group (18.96% Vs 11.43% and 37.73% Vs 22.86%, respectively).
  
  
  CONCLUSIONS
  The extended letrozole regimen had a superior efficacy as compared with clomiphene citrate in patients of unexplained infertility undergoing superovulation and IUI.
  
  
  BACKGROUND
  ClinicalTrials.gov, NCT01232075.
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medicine, Cairo University, Cairo, Egypt. umfrfouda@yahoo.com
authors.forename: Usama M
authors.initials: UM
authors.lastname: Fouda
authors.forename: Ahmed M
authors.initials: AM
authors.lastname: Sayed
mesh_terms: D000328:Adult; D047072:Aromatase Inhibitors / Q000008:administration & dosage; D002996:Clomiphene / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007247:Infertility, Female / Q000628:therapy*; D007314:Insemination; D000077289:Letrozole; D009570:Nitriles / Q000008:administration & dosage*; D010062:Ovulation Induction / Q000379:methods*; D011247:Pregnancy; D018873:Pregnancy Rate; D011960:Receptors, Estrogen / Q000187:drug effects; D013480:Superovulation / Q000187:drug effects*; D014230:Triazoles / Q000008:administration & dosage*
chemical_list: D047072:Aromatase Inhibitors; D009570:Nitriles; D011960:Receptors, Estrogen; D014230:Triazoles; D002996:Clomiphene; D000077289:Letrozole