Success rate with repeated cycles of in vitro fertilization-embryo transfer

Objective: To analyze data from a large multicenter study to determine whether pregnancy and delivery rates decrease with repeated IVF-ET cycles. Design: Multicenter retrospective study. Setting: Participating centers from the Society of Assisted Reproductive Technology. Patient(s): Fifty-four centers contributed 4,043 cycles of oocyte retrieval for uterine transfer. Intervention(s): Oocyte retrieval for uterine transfer. Main Outcome Measure(s): Pregnancy and delivery rates, analyzed according to age, program success rate, and whether the program was doing assisted hatching. Result(s): Pregnancy and delivery rates for cycles 1, 2, 3, 4, and >4 were 33.7% and 27.0%, 33.9% and 27.4%, 28.9% and 23.4%, 25.9% and 16.1%, and 21.0% and 15.4%, respectively. The pregnancy rate decreased significantly for >4 cycle; delivery rate decreased significantly for cycles 4 and >4. Assisted hatching was strongly related to better odds of pregnancy (OR, 1.50) and delivery (OR, 1.44) in women under age 40, and for pregnancy (1.64) in women age 40-42 years. Conclusion(s): Success rates do not decrease markedly with repeated IVF attempts, and the decrease did not change with program success rate, suggesting the IVF population is not markedly heterogeneous. Uncontrolled studies of new treatments for cycle repeaters cannot assume that success rate is poor without a treatment change. (C) 1998 by American Society for Reproductive Medicine.