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.