Metformin-letrozole in comparison with Metformin-clomiphene citrate in clomiphene-resistance PCOS patients undergoing IUI

BACKGROUND Polycystic ovary syndrome (PCOS) is associated with approximately 75% of women who suffer from infertility due to anovulation. Additionally, around 20- 25% of anovulatory women with PCOS do not respond at all to clomiphene citrate and are considered to be "clomiphene- resistant". Aromatase inhibitors have been suggested as an alternative treatment to clomiphene as the discrepancy between ovulation and pregnancy rates with clomiphene citrate has been attributed to its anti-estrogenic action and estrogen receptor depletion. OBJECTIVE The aim of this study is to compare results of Metformin-letrozole with Metformin-clomiphene citrate in clomiphene resistance PCOS patients undergoing IUI. MATERIALS AND METHODS In this single blind randomized trial, ovarian cycles were studied in 100 clomiphene- resistant patients with PCOS. The inclusion criteria were patients who received 150mg clomiphene citrate daily for 3 cycles and failed to become pregnant. The patients were matched for their age, body mass index (BMI), and infertility period. They were randomly allocated to a metformin-letrozole group (n=50) and a metformin-clomiphene citrate group (n=50). Chemical and clinical pregnancies were assessed after IUI. Abortion rates were determined in both groups. RESULTS Regarding pregnancy rate, there was no significant difference between the two groups. One miscarriage (2%) occurred in the metformin-clomiphene citrate group, whereas none was seen in the metformin-letrozole group. CONCLUSION There is no significant difference in pregnancy rate between clomiphene citrate and letrozole groups although it has been 2% in the former and 5% in the latter.