Comparison of two aromatase inhibitors in women with clomiphene-resistant polycystic ovary syndrome

Abstract

Letrozole and anastrozole are potent aromatase inhibitors (AI) that peripherally decrease the production of estrogens from androgens w1x. They are highly selective, orally administered, and easy to monitor w2x. This study was carried out to compare their effect on producing ovulation and conception in infertile, clomiphene-resistant women with polycystic ovary syndrome (PCOS). Forty non-fertile women with PCOS were enrolled in this study. Tubal, peritoneal, and uterine causes of infertility were excluded by laparoscopic hysterosalpingogram or by ultrasonography. Specific endocrine abnormalities and causes of infertility due to the husbands were also excluded. Patients had to end clomiphene treatment at least 2 months before enrolment. Serum levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone, and estradiol (E ) were 2 assessed and ultrasound examinations were performed on day 1 or 2 of the menstrual cycle, and then from day 9 on alternating days, ending with administration of human chorionic gonadotropin (hCG). Endometrial thickness and pulsatility index