RESUMO
OBJECTIVE: To determine the best practices of intrauterine insemination with the partner's fresh sperm. DESIGN: Prospective multicenter observational study. SETTING: Assisted reproduction technology (ART) centers. PATIENT(S): Seven hundred and seven patients entering the program, regardless of age or cause of infertility. INTERVENTION(S): Intrauterine insemination by standard procedures. MAIN OUTCOME MEASURE(S): Effect of patient characteristics (duration of infertility, indications, age, parity, body mass index, semen parameters) as well as IUI parameters on delivery rates per couple or per attempt. RESULT(S): The overall live birth rate was 11.4% per cycle, varying from 8.4% to 17.6% between centers. The main differences in practice that had a statistically significant impact on the delivery rate were the use of gonadotropin-releasing hormone (GnRH) antagonists (15.2% with versus 9.4% without) and the number of mature recruited follicles (9.4% for one versus 15.2% for two). CONCLUSION(S): Our results indicate that the use of GnRH antagonists has a positive effect on the delivery rate, especially in the multifollicular stimulations that are required when women are older than 27 years.