Fertility preservation is the technique performed to extract gametes (male or female) from the body and preserve them for future use. Perhaps the appropriate term would simply be gamete preservation, since even if we preserve gametes for future use, if they are genetically defective or if we preserve a low quantity, we will not be guaranteeing a correct preservation of fertility, which can lead to future misunderstandings.
Hence also the importance of correct advice before carrying out this practice and the convenience of going to a good fertility specialist to advise us and indicate the recommended prior tests before preserving our gametes.
In addition, the ovules accumulate genetic mutations throughout their lives, so it is not uncommon that after the age of 40 we not only have very few ovules available, but also that these are not of good quality, which makes it very difficult to obtain one. pregnancy naturally.
As for the male gametes (spermatozoa), these are not depleted throughout a man’s life, but begin to be produced from puberty (between the ages of 11 and 15) and constantly, with new spermatozoa available. every 72 days or so.
Until now it had been considered that, contrary to what happens with the gametes of women, the gametes of men were equally valid regardless of age. However, there are more and more studies that demonstrate the negative effect of the male’s age on achieving a full-term pregnancy.
It is important to note that women are born with a certain number of gametes (known as ovules) and that this number decreases throughout the woman’s fertile stage. From the age of 35 and depending on the follicular endowment at the time of the woman’s birth, genetic and environmental factors, a more abrupt decline in fertility normally begins.
WHEN IS GAMETE PRESERVATION RECOMMENDED?
Currently our pace of life, as well as socio-economic factors push women to delay motherhood. Therefore, fertility preservation is recommended in the following cases:
In women with low ovarian reserve or with early menopause.
In women who wish to postpone maternity.
In women who are going to receive chemotherapy or radiotherapy.
In the case of women who want to postpone maternity, it is recommended to carry out gamete preservation before the age of 35 since, as we have previously commented, from this age onwards a more abrupt decrease in the number of oocytes begins and as the time also of its quality, which would reduce the chances of achieving a pregnancy with those ovules in the future.
However, fertility preservation in men is generally performed when the man suffers from a disease that affects spermatozoa, to preserve fertility before chemotherapy treatment or before performing a vasectomy. In the case of men, semen freezing is not yet widespread when they wish to postpone paternity.
WHY PRESERVE GAMETES INSTEAD OF EMBRYOS?
In some cases, such as women with cancer, the fastest and sometimes the only viable option is oocyte preservation, since in these patients there is a significant time limitation. In other cases, simply not having a partner makes women decide to preserve their eggs.
In my opinion, the best way to prevent future problems is the preservation of gametes instead of embryos. Let’s take the case that a couple decides to freeze embryos and said couple breaks before being used, both members of the couple would have problems using those embryos or they simply did not want to do so and therefore it would not have served to preserve them. those embryos.
FERTILITY IN THE TIME OF COVID
During the pandemic that we have experienced, many women have seen their fertility treatments affected since most fertility centers, both public and private, suspended their activity on recommendations from the main fertility associations. Not only because it was not known if the virus could be passed from mother to child, but also because in that situation where hospitals were overwhelmed, it was not the best time for a pregnant woman to have an obstetric complication.
The fact is that, during this pandemic, many women about to start fertility treatment or with treatment already started have been aware of the importance of time when we talk about fertility and reproduction, since waiting a few months to start treatment fertility can be decisive for the success or failure of dicho treatment.
That is why the preservation of fertility is highly recommended and it is recommended that it be done ON TIME if we want to be parents in the future, since we will have “young” and better quality gametes for future use.
Is there an age limit to use cryopreserved oocytes/embryos?
According to Law 14/2006 on Assisted Reproduction Techniques, the oocytes and/or embryos may be cryopreserved as long as the clinically appropriate requirements for the practice of the assisted reproduction technique are met. It is not advisable to postpone pregnancy beyond the age of 50 since complications during pregnancy increase with age.
Does cryopreservation affect gametes and/or embryos?
No, neither the technique itself nor the time that they remain frozen seem to affect the viability of said gametes after thawing or the success of a future assisted reproduction treatment.
However, it must be taken into account that survival rates will depend on the quality of the gametes and embryos and the particular characteristics of each house.
In other words, if we freeze poor-quality oocytes, obviously poor-quality oocytes will be thawed and the result of the treatment will be a consequence of this and not of the technique itself or the time they have spent frozen.
Alicia Tio Castro- Embryologist and Fertility Consultant