Objective: To assess the real biological efficiency of assisted reproduction technology (ART) cycles by using a new metric called oocyte to baby rate, where live babies born (LBB) are reported in relation to the number of oocytes retrieved and used.
Design: Retrospective analysis of clinical and embryological database.
Setting: University center.
Patient(s): Patient's cycles (n = 572) divided by age (<35, 35 to 37, 38 to 40, 41 to 42, >42 years) and by oocyte donors.
Main outcome measure(s): Total number of oocytes collected, the number of embryos transferable (fresh and frozen) and corresponding oocyte to LBB rates. In patients with remaining frozen embryos, the final LBB was estimated according to our reported rates.
Result(s): A total of 572 oocyte retrievals yielded 7213 oocytes. The total number of transferred and frozen embryos was 2252 (a utilization rate of 31.2%). The LBB from fresh embryo transfers was 262 with an additional 64 LBB expected from frozen embryos. The overall oocyte to LBB rate was 4.6% (326 babies born). When analyzed by groups, the oocyte to baby rate was best in donor oocyte cycles (6.8%), and declined to 1% for patients >40. There was no increase in oocyte to LBB if >15 oocytes were obtained.
Conclusion(s): During ART cycles, only approximately 5% of fresh oocytes produce a baby. The time has come to investigate new methods of oocyte viability assessment and consider changing current ART practice to recruit fewer oocytes.