At Lucina Egg Bank, we report pregnancy rates based on each egg thawing cycle (not on a per-patient basis). For instance, if one patient undergoes a thawing cycle and conceives with it, and another patient has a thawing cycle and fails to get pregnant, Lucina would report the outcomes of the two cycles as a 50-percent pregnancy rate. If the second patient received another cohort of eggs from Lucina and conceived, we would report the outcomes of the three cycles as a 67 percent pregnancy rate.
However, many other egg banks report pregnancy rates based on each patient (not per cycle). So, using the example described above, these egg banks might report a 100 percent pregnancy rate (since both patients conceived, whereas three cycles were completed). This kind of calculation is often classified as a cumulative pregnancy rate. When weighing up statistics from various egg banks, you need to confirm that the calculations are done the same way. This will help ensure the comparisons are fair and reflect the true probability of pregnancy in each case.