How Many Oocytes Should I Freeze?

Although the exact survival rate of oocytes after thawing frozen oocytes is not known, the survival rate is reported to be about 40-90%.
Furthermore, the pregnancy rate per fertilized egg in ICSI after oocyte thawing is considered to be 20~35% (when frozen at the age of 39 or younger), so it is desirable to freeze and store at least 10 oocytes if possible, considering the oocyte survival rate and subsequent pregnancy rate.

Our hospital calculated the number of frozen oocytes required to give birth to one child from statistics for each age. The birth rate (%) for each number of thawed oocytes is as follows.

  10 oocytes 20 oocytes 30 oocytes 40 oocytes
32years old 65.5% 88.1% 95.9% 98.6%
38years old 51.1% 76.1% 88.3% 94.3%
42years old 42% 66.3% 80.5% 88.7%

This table is based on Cil AP, Bang H, Oktay K. Age-specific probability of live birth with oocyte cryopreservation: an individual patient data meta-analysis. Fertil Steril. 2013; 100 (2): 492-499. This research originates with the Oak Clinic Group.

Many patients try to freeze as many oocytes as possible, hopefully this guide can help to build confidence.