Administration of progesterone before oocyte retrieval negatively affects the implantation rate

Objective: To compare the efficacy of two clinically accepted methods of progesterone supplementation during IVF. Design: Prospective randomized trial. Setting: A university-based IVF program. Patient(s): Three hundred fourteen stimulated IVF cycles between January 1993 and October 1994. Intervention(s): Patients were assigned to one of two luteal phase progesterone regimens by a random permuted block design. In protocol A, 12.5 mg of IM progesterone was given 12 hours before oocyte retrieval; in protocol B, 25 mg of IM progesterone was given on the day of oocyte retrieval. Main Outcome Measure(s): Clinical pregnancy. Result(s): Patient demographic characteristics, including age, diagnosis, number of oocytes retrieved and fertilized, and number of embryos transferred, were not different between the two groups. There was no difference in the rate of cycle cancellation between the groups. One hundred forty ETs were performed in patients assigned to protocol A and 142 in patients assigned to protocol B. The clinical pregnancy rate in group A was 12.9% compared with 24.6% in group B. Conclusion(s): The administration of progesterone before oocyte retrieval is associated with a lower pregnancy rate than the administration of progesterone after oocyte retrieval.