title: A randomized trial of letrozole versus clomiphene citrate in women undergoing superovulation.
abstract: OBJECTIVE
  To compare the effects of the aromatase inhibitor letrozole (7.5 mg) and clomiphene citrate (CC; 100 mg) in women undergoing superovulation and IUI.
  
  
  METHODS
  Prospective randomized trial.
  
  
  METHODS
  University teaching hospital.
  
  
  METHODS
  We studied a total of 238 cycles of superovulation and IUI in women with idiopathic infertility.
  
  
  METHODS
  Patients were randomized into treatment with 7.5 mg of letrozole daily (74 patients, 115 cycles) or 100 mg of CC daily (80 patients, 123 cycles).
  
  
  METHODS
  Number of follicles, endometrial thickness, pregnancy rate, and miscarriage rate.
  
  
  RESULTS
  The mean age, parity, and duration of infertility in both groups of patients were similar. There was no significant difference between the total number of developing follicles in the letrozole (5.7 +/- 3.7) and in the CC groups (4.8 +/- 2.5). The number of follicles of > or =14 mm and of >18 mm were 2.1 +/- 1.2 and 1.4 +/- 0.7 in the letrozole group, and 1.7 +/- 0.9 and 1.1 +/- 0.5 in the CC group, respectively. No difference was found in the endometrial thickness between the two groups (7.1 +/- 0.2 mm in the letrozole group, 8.2 +/- 5.9 mm in the CC group). The pregnancy rate per cycle was 11.5% in the letrozole group and 8.9% in the CC group. Four of the 11 pregnancies in the CC group resulted in a miscarriage (36.6%).
  
  
  CONCLUSIONS
  Superovulation and IUI with letrozole and CC are associated with similar pregnancy rates, but the miscarriage rate is higher with CC. The ideal dose of letrozole remains unknown and further study is needed.
authors.affiliation: Department of Obstetrics and Gynecology, McGill University, Montreal, Québec, Canada.
authors.forename: Haya
authors.initials: H
authors.lastname: Al-Fozan
authors.forename: Maha
authors.initials: M
authors.lastname: Al-Khadouri
authors.forename: Seang Lin
authors.initials: SL
authors.lastname: Tan
authors.forename: Togas
authors.initials: T
authors.lastname: Tulandi
mesh_terms: D000022:Abortion, Spontaneous / Q000139:chemically induced / Q000453:epidemiology; D000328:Adult; D047072:Aromatase Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D002996:Clomiphene / Q000009:adverse effects / Q000627:therapeutic use*; D004717:Endometrium / Q000000981:diagnostic imaging; D005260:Female; D005300:Fertility Agents, Female / Q000009:adverse effects / Q000627:therapeutic use*; D006801:Humans; D015994:Incidence; D007247:Infertility, Female / Q000188:drug therapy / Q000628:therapy; D007315:Insemination, Artificial; D000077289:Letrozole; D009570:Nitriles / Q000009:adverse effects / Q000627:therapeutic use*; D006080:Ovarian Follicle / Q000000981:diagnostic imaging; D011247:Pregnancy; D018873:Pregnancy Rate; D011446:Prospective Studies; D013480:Superovulation; D014230:Triazoles / Q000009:adverse effects / Q000627:therapeutic use*; D014463:Ultrasonography
chemical_list: D047072:Aromatase Inhibitors; D005300:Fertility Agents, Female; D009570:Nitriles; D014230:Triazoles; D002996:Clomiphene; D000077289:Letrozole