The effect of oral contraceptive pill for cycle scheduling prior to GnRH-antagonist protocol on IVF cycle parameters and pregnancy outcome.

Objective: To evaluate the effect of oral contraceptive pills (OCP) pretreatment on IVF cycle outcome in GnRH-antagonist protocol.

Design: Retrospective cohort study.

Setting: Major tertiary university-affiliated center.

Patients: All patients treated with GnRH antagonist in our IVF unit during the last 3 years were included in the study. Overall 1,799 IVF cycles were performed. Of these, in 604 cycles OCP pretreatment was used prior to GnRH-antagonist for cycle scheduling. Patients were divided into two age groups-young group aged < or = 35 years and older group aged > or = 36 years.

Interventions: The young group underwent 927 cycles, 281 cycles with OCP pretreatment and 646 cycles without. The older group underwent 872 cycles, 323 cycles with OCP pretreatment and 549 cycles without. Data was analyzed within each age group.

Main Outcome Measures: Treatment duration and total dose of FSH IU used for stimulation, number of oocytes retrieved, implantation and pregnancy rates.

Results: All OCP-pretreated cycles required significantly longer stimulation than non-pretreated cycles (young: 10.76 vs. 9.21 days; older: 10.48 vs. 8.73 days, respectively) and higher total dose of FSH IU (young: 3,210 IU vs. 2,565 IU; older: 4,973 IU vs. 3,983 IU, respectively). There were no other differences in cycle characteristics between groups. Implantation and pregnancy rates were not affected by OCP pretreatment.

Conclusions: OCP pretreatment can be offered as a mode for cycle scheduling prior to GnRH-antagonist protocol, though it may be associated with longer stimulation and higher gonadotropin consumption.