Oocyte cryopreservation (OC) is a procedure that allows women to preserve their fertility in anticipation of the well-known age-related decline in fertility. It is an approach that is becoming increasingly popular – of the 300,000 ART procedures performed in 2019, 16,000 were for OC. This is an option for women who wish to delay child-bearing due to career goals, lack of a suitable partner, or financial reasons.
Background
A woman is born with all the eggs she will ever have, numbering about one million at birth. There is a progressively accelerating loss such that by age 37 that number is down to about 25,000, and by age 51 there are less than 1000. This accompanied by the increasing percentage of remaining oocytes that are genetically abnormal accounts for the dramatic decline in fertility as women age. The relative fertility rate of a woman in her “early 30s is 15-19% lower than that of someone in their early 20’s, 26-46% lower by the late 30s, and a striking 95% lower by the early 40s.” (J. Clin, Med. 2923, 12(10), 3542).
Timing
The average age at which women pursue OC is about 37. There is some suggestion that pursuing this at an earlier age would be beneficial. “The European Society of Human Reproduction and Embryology (ESHRE) Task Force on Ethics and Law recommends planned OC to be performed before age 35…. and should not be recommended after age 38”. (ibid) The American Society of Reproductive Medicine acknowledges that earlier is better, but does not specify ages.
One marker of ovarian reserve is an AMH (Anti-Mullerian Hormone) level. This is a simple blood test that can provide some guidance and perspective as to timing and chances of success. This is readily available and is often the first test performed when considering OC.
The Procedure
A detailed description of the procedure is beyond the scope of this paper. Basically, it is the first half of an IVF cycle with the induction of development of multiple oocytes and their retrieval during a procedure that lasts about ten minutes (patients do receive sedation for this and it is both painless and safe). The oocytes are then frozen for later use. This will be discussed in much greater detail should you make an appointment to talk to one of our physicians.
Chances
“In general, it is preferable to freeze as many mature oocytes as possible, as the estimated efficiency from a vitrified and warmed oocyte to live born child is only 6.5% per oocyte ranging from 5.2% for women age over 38 to 7.4% for women under the age of 30 at the time of the OC. These rates are comparable to that for fresh oocytes which is 6.7% overall”. (ibid) “ Higher numbers of mature oocytes are needed to be frozen with increasing age. For example, an individual under 35 years of age should aim to freeze 10 mature oocytes to have a 70% probability of having at least 1 birth. To achieve this same 70% probability a 38-year-old, 40-year-old, and 42-year-old would require about 20, 35, and 55 mature oocytes respectively” (ibid)
Another study showed that “ two thirds of patients were able to achieve a 50% live birth rate and just over half were able to achieve a 70% live birth rate with a single cycle of OC. The data are more reassuring with 2 cycles of OC, from which nearly 80% reach the 50% live birth rate threshold. … Those with an AMH value of greater than 1.995 ng/dL were 7 times more likely to achieve a 60% live birth rate with the first OC cycle compared with those with an AMH lower than that level”. (Maslow et al J. Assist. Reprod. Genet. 2020, 37, 1637–1643.)
Costs
The cost of each individual attempt will be discussed with the patient personally by a member of our business office. There are even some insurance plans that cover OC, and your representative will help you determine exactly what to expect.
Conclusion
OC is a viable and increasingly popular option for women who for one reason or another wish to delay child-bearing.