A randomized trial of letrozole versus clomiphene citrate in women undergoing superovulation.
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.
Al-Fozan
Haya
H
Department of Obstetrics and Gynecology, McGill University, Montreal, Québec, Canada.
Al-Khadouri
Maha
M
Tan
Seang Lin
SL
Tulandi
Togas
T
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
D047072:Aromatase Inhibitors; D005300:Fertility Agents, Female; D009570:Nitriles; D014230:Triazoles; D002996:Clomiphene; D000077289:Letrozole