Efficacy of combined metformin-letrozole in comparison with metformin-clomiphene citrate in clomiphene-resistant infertile women with polycystic ovarian disease.
BACKGROUND
Adding metformin to clomiphene citrate in clomiphene-resistant polycystic ovary syndrome (PCOS) patients increases ovulatory response. However, because of anti-estrogenic effects of clomiphene it may be associated with lower pregnancy rate, offsetting the ovulation rate benefit. Letrozole is an aromatase inhibitor which induces ovulation without anti-estrogenic effects.


METHODS
Infertile women with PCOS were randomly divided into metformin-letrozole (29 patients) and metformin-clomiphene groups (30 patients). After an initial 6-8 weeks of metformin, they received either letrozole (2.5 mg) or clomiphene (100 mg) from day 3-7 of their menstrual cycle. Estradiol (E2) levels, number of follicles, pregnancy rates and endometrial thickness were measured on the day of HCG administration.


RESULTS
Mean total E2 and E2 per mature follicle were significantly higher in clomiphene group without a difference in mean number of mature follicles >18 mm and ovulation rate. Endometrial thickness was significantly higher in letrozole group. The pregnancy rate in letrozole group (10 patients, 34.50%) as compared with clomiphene group (5 patients, 16.67%) did not show significant difference, whereas full-term pregnancies were higher in letrozole group [10 patients (34.50%) versus 3 patients (10%)].


CONCLUSIONS
In clomiphene-resistant PCOS patients, the combination of letrozole and metformin leads to higher full-term pregnancies.
Department of Infertility & IVF, Vali-e-Asr Hospital, Tehran University of Medical Sciences, Tehran, Iran. fsohrabvand@yahoo.com
F
F
Sohrabvand
Sh
Sh
Ansari
M
M
Bagheri
D000328:Adult; D047072:Aromatase Inhibitors / Q000008:administration & dosage; D002996:Clomiphene / Q000008:administration & dosage*; D004351:Drug Resistance; D004359:Drug Therapy, Combination; D004717:Endometrium / Q000378:metabolism / Q000473:pathology; D005260:Female; D005300:Fertility Agents, Female / Q000008:administration & dosage; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage; D007247:Infertility, Female / Q000188:drug therapy*; D000077289:Letrozole; D008687:Metformin / Q000008:administration & dosage*; D009570:Nitriles / Q000008:administration & dosage*; D011085:Polycystic Ovary Syndrome / Q000188:drug therapy*; D011247:Pregnancy; D016037:Single-Blind Method; D014230:Triazoles / Q000008:administration & dosage*
D047072:Aromatase Inhibitors; D005300:Fertility Agents, Female; D007004:Hypoglycemic Agents; D009570:Nitriles; D014230:Triazoles; D002996:Clomiphene; D000077289:Letrozole; D008687:Metformin