Natural cycle in vitro fertilization-embryo transfer at the University of Ottawa: an inefficient therapy for tubal infertility

OBJECTIVE: To describe our experience with natural cycle IVF making clinical and endocrine comparisons with our standard stimulated cycle IVF program. DESIGN: We attempted 75 natural IVF-ET cycles with hCG given to preempt the LH surge and compared these with 450 attempts at standard superovulation IVF-ET done in our unit during the same time period. PATIENTS: Natural cycle patients are normally ovulating women < age 38. Superovulation IVF-ET patients are all < 41 years old. Patients in both groups had partners with normal semen parameters and tubal factor infertility. MAIN OUTCOME MEASURES: Cancellation rates, pregnancy rates per egg retrieval, per ET procedure, and luteal phase E2:P ratios of the treatment cycles are compared. RESULTS: There were 35 of 75 (47%) natural cycle and 112 of 450 (25%) superovulation cycle cancellations. An egg was retrieved in only 24 of 40 (60%) natural cycles and 336 of 338 (99%) superovulation egg retrieval procedures. Pregnancy rates per ovum pick-up procedure were significantly higher: 65 of 338 (19%) in the superovulation versus 2 of 40 (5%) in the natural cycle groups. Pregnancy rates per ET were not significantly different between natural IVF-ET, 2 of 18 (11%) and superovulation IVF-ET, 65 of 298 (22%). The E2:P ratios 5 days after ET were similar in both groups at 18 +/- 4 after natural IVF-ET and 21 +/- 18 after superovulation IVF-ET. CONCLUSIONS: 1] Cancellation rates for natural cycle IVF are very high. 2] Midluteal E2:P ratios are the same in both groups. 3] Pregnancy rates per egg retrieval are significantly lower for natural versus superovulation IVF-ET. 4] In our experience, natural cycle IVF-ET is an inefficient therapy for tubal infertility compared with superovulation IVF-ET.