Midluteal buserelin is superior to early follicular phase buserelin in combined gonadotropin-releasing hormone analog and gonadotropin stimulation in in vitro fertilization.

OBJECTIVE

To establish whether time to down-regulation and pregnancy and live birth rates were different when buserelin acetate was started in the midluteal phase or early follicular phase in IVF-ET patients.

DESIGN

Prospective, controlled, randomized, parallel-group multicenter clinical study.

SETTING

Women attending seven infertility clinics.

PATIENTS

One hundred twenty-four women with tubal or unexplained infertility with normal menstruation and fertile partners.

INTERVENTIONS

Intranasal buserelin acetate started in the midluteal or early follicular phase combined with standard hMG and hCG stimulation after achievement of down-regulation. Established IVF-ET methods.

MAIN OUTCOME MEASURES

Duration of down-regulation; clinical pregnancy and live birth rates.

RESULTS

Kaplan-Meier estimations of the duration of down-regulation were 15.5 days when buserelin acetate was started in the early follicular phase (127 cycles) and 14.6 days when it was started in the midluteal phase (96 cycles). This difference was statistically significant. The pregnancy rates per first treatment cycle, treatment cycle, oocyte retrieval, and ET were significantly higher when buserelin acetate was started in the midluteal phase. The live birth rates were also higher, but only significantly so for the rate per first treatment cycle.

CONCLUSIONS

Clinical pregnancy and live birth rates are better when buserelin acetate is started in the midluteal phase rather than the early follicle phase before hMG and hCG stimulation in preparation for IVF-ET.