Stability of in vitro fertilization-embryo transfer success rates from the 1989, 1990, and 1991 Clinic-Specific Outcome Assessments

Abstract

Objective: To determine if the differences in IVF-ET success rates among clinics are due to chance alone.

Design: Retrospective analysis of data reported by individual clinics.

Setting: One hundred seventy-five clinics in 1989, 192 clinics in 1990, and 208 clinics in 1991 that reported IVF-ET success rates to the Society for Assisted Reproductive Technology and the American Society for Reproductive Medicine (formerly The American Fertility Society).

Patients: Women < 40 years of age with no male factor.

Intervention: In vitro fertilization-ET.

Main outcome measure: Delivery rate per retrieval and delivery rate per transfer.

Results: The hypothesis that the differences among IVF-ET success rates for clinics is due to chance alone can be rejected. Seven clinics were found to have pregnancy rates significantly higher than average and six clinics were found to have pregnancy rates significantly lower than average. Significant correlations were found between different years in the success rates for individual clinics but not for success as a function of the number of patients treated.

Conclusions: Success rates for a few clinics are significantly different from the average success rate, but success rates must be used with caution in selecting a clinic.