Objective: Our aim is to investigate the 10-year results of assisted reproductive technique (ART) cycles in our in vitro fertilization (IVF) clinic and to evaluate the effects of treatment protocols on ART outcomes.

Methods: Medical records of 2.795 IVF cycles of 1.964 infertile couples who were admitted to our IVF unit between 1998 and 2007 were evaluated retrospectively. A short or long protocol was performed with a gonadotropin-releasing hormone (GnRH)-analog and a GnRH-antagonist. Factors that may affect ART success or failure were evaluated and interpreted.

Results: The pregnancy rates per IVF cycle and per transfer were 21.07% and 24.4%, respectively. The highest pregnancy rate was attained when the cause of infertility was unexplained (p<0.001). Treatment with the long protocol resulted in a higher pregnancy rate than treatment with either the short or the long the antagonist protocol (p<0.001). The pregnancy rate was higher when the third-day step-down protocol was applied, compared with any of the fifth-day step-down, continuous-dose, and step-up protocols. The number of cycles, duration of infertility, age, follicle stimulating hormone level on the 3rd day of menstruation, E2 level measured on the day of human chorionic gonadotropin, total gonadotropin dose, total number of oocytes collected, and number of total embryos transferred affected the success rate of ART per cycle.

Conclusion: Unexplained infertility, use of the long protocol, application of the third-day step-down protocol, and application of intracytoplasmic sperm injection and luteal support are associated with higher pregnancy rates. The number of oocytes collected, number of embryos transferred, and the quality of the transferred embryos are important factors affecting pregnancy rates.