RESUMEN
To assess the efficacy of luteal phase support [LPS] using intravaginal progesterone [P] on pregnancy rate in Iranian women with polycystic ovarian syndrome [PCOS] who used a combination for ovulation induction consisting of letrozole or clomiphene citrate [CC] and human menopausal gonadotropin [HMG]. This was a randomized clinical trial undertaken in a fertility clinic in Kashan, Isfahan Province, Iran. A total of 198 patients completed treatment and follow up. Base on chosen ovulation induction programs, they were divided into two following groups: i. CC group [n=98] used a combination consisting of CC [100 mg x 5 day] and HMG [150 IU x 5 day] and ii. letrozole group [n=100] used a combination consisting of letrozole [5 mg x 5 day] and HMG [150 IU × 5 day]. After human chorionic gonadotropin [hCG] administration [5000 IU], the patients [n=122] who randomly received intravaginal P [Cyclogest, 400 mg daily] were included in LPS group, while the rest [n=123] were included in non-P cycles group. The outcome was the comparison of chemical pregnancy rate between the groups. Our findings showed that LPS was associated with a 10% higher pregnancy rate than in non-P cycles, although this difference did not reach statistical significant [p=0.08]. LPS improved pregnancy rate in both CC [4%] and letrozole [6%] groups. In addition, patients who used letrozole for ovulation induction along with intravaginal P showed higher pregnancy rates than CC group. Administration of vaginal P for LPS may improve the pregnancy rate in women with PCOS using letrozole or CC in combination with HMG for ovulation induction [Registration Number: IRCT201206072967N4]