title: Letrozole usage adjuvant to gonadotropins for ovulation induction for patients with clomiphene citrate failure.
abstract: OBJECTIVE
  To compare cycle properties of ovulation induction (OI) with gonadotropin alone or combined with letrozole in the patients with previous clomiphene citrate (CC) failure.
  
  
  METHODS
  In this prospective study, 40 patients with previous at least three times CC cycle failure were evaluated. Half of them received 2.5 mg letrozole on days 3-7 of the menstrual cycle and recombinant follicle stimulating hormone (rFSH) starting on day 5. The other half of the patients received only rFSH starting on day 3. Groups were compared according to the OI duration, gonadotropin dosage, endometrial thickness, estradiol (E2) levels on day of human chorionic gonadotropin (HCG) administration and follicle count.
  
  
  RESULTS
  Total rFSH dose, the E2 levels on the day of HCG and >18 mm follicle count was significantly lower and OI duration was significantly shorter in rFSH + letrozole group. Mean endometrial thickness was not different between groups.
  
  
  CONCLUSIONS
  Adding letrozole to gonadotropin in OI cycles decreases total gonadotropin dose and induction duration without any adverse effects on endometrial thickness. Monoovulation is better achieved by adding letrozole to gonadotropin stimulation without decreasing pregnancy rates.
authors.affiliation: Dr. Zekai Tahir Burak Education and Research Hospital, Ankara, Turkey.
authors.forename: Ulku
authors.initials: U
authors.lastname: Ozdemir
authors.forename: Gulnur
authors.initials: G
authors.lastname: Ozaksit
authors.forename: Ayse Nur
authors.initials: AN
authors.lastname: Cakir Gungor
authors.forename: Munibe
authors.initials: M
authors.lastname: Aydogan
mesh_terms: D000328:Adult; D047072:Aromatase Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D002996:Clomiphene / Q000627:therapeutic use; D004359:Drug Therapy, Combination; D004717:Endometrium / Q000000981:diagnostic imaging / Q000187:drug effects; D004958:Estradiol / Q000097:blood; D005260:Female; D005300:Fertility Agents, Female / Q000627:therapeutic use; D005640:Follicle Stimulating Hormone / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D007247:Infertility, Female / Q000188:drug therapy*; D000077289:Letrozole; D009570:Nitriles / Q000494:pharmacology / Q000627:therapeutic use*; D010062:Ovulation Induction; D011247:Pregnancy; D018873:Pregnancy Rate; D017211:Treatment Failure; D014230:Triazoles / Q000494:pharmacology / Q000627:therapeutic use*; D014463:Ultrasonography; D055815:Young Adult
chemical_list: D047072:Aromatase Inhibitors; D005300:Fertility Agents, Female; D009570:Nitriles; D014230:Triazoles; D002996:Clomiphene; D004958:Estradiol; D000077289:Letrozole; D005640:Follicle Stimulating Hormone