The association between follicular size on human chorionic gonadotropin day and pregnancy rate in clomiphene citrate treated polycystic ovary syndrome patients

OBJECTIVE: To examine leading follicle size on human chorionic gonadotropin (hCG) day and pregnancy rate in anovulatory polycystic ovary syndrome (PCOS) patients treated with clomiphene citrate (CC). DESIGN: Retrospective cohort study. SETTING: Fertility clinics in women's health centers. PATIENTS: Data on 291 infertile women with PCOS and irregular cycles who underwent 685 CC treatment cycles were used. Only cycles with one or two follicles >14 mm were included. hCG was administered once the leading follicle reached the size of 17-24 mm. MAIN OUTCOME MEASURE(S): Pregnancy rates in relation to leading follicle size. RESULTS: Mono/bi-follicular response was observed in 418 cycles. Pregnancy rates were highest (13.6-18.6%) when hCG was administered in the presence of an 18-22 mm follicle, lowest with 17 mm, 23 mm and 24 mm (8.8%, 8.8% and 5.7%, respectively). No differences were observed in pregnancy rates between mono and bi-follicular cycles. CONCLUSIONS: In CC treatment, hCG should be administered when follicular size is at the range of 18-22 mm.