What is fertility preservation? – cryopreservation of eggs and sperm

Today, advances in medicine help to provide solutions so that men and women can fulfill their desire to have children at the right time.

Fertility preservation consists of collecting and freezing eggs and sperm in special straws, or other freezing methods and keeping them immersed in liquid nitrogen for an unlimited time. Thus, these cells can be kept intact until the moment one wishes to have children. The would be parent can then use them in an assisted reproduction treatment with high success rates.

Freezing ovarian and testicular tissue is an alternative to egg and sperm cryopreservation. However, the safety and effectiveness of these methods have not yet been proven.

When do you need to preserve fertility?

Mainly, there are two specific cases when it is recommended to preserve fertility:

• Cancer patients: Chemotherapy and radiotherapy treatments are very aggressive and can attack the precursor cells of eggs and sperm. In these cases, the gametes can be frozen to avoid having to resort to egg and/or sperm donors in the future.
• Desire to delay childbearing: a woman is born with a finite number of eggs, which decreases over time. In addition, not only does the number of eggs decrease, but their quality also decreases.

Indications necessary to preserve fertility

Dr. Irene Romero, specialist in Gynecology and Obstetrics, comments that:

Today we would like to talk about the preservation of fertility as an opportunity. An opportunity for patients to be their own donors in case they need to recieve egg donation.

Fertility preservation for women

Today, the number of women who choose to preserve their fertility has grown considerably. The main cause of this increase has been the increasingly marked tendency to delay motherhood, either because of lifestyle reasons or because of the socio-economic situation in which we live.

Other reasons why many women decide to preserve their fertility is because they are going to undergo cancer treatment or because they suffer from diseases that affect the ovarian reserve, such as endometriosis.

Preserving male and female fertility

The following are the different alternatives that women have to preserve their reproductive function.

Egg vitrification

Egg vitrification is a fertility treatment that consists of the ultra-fast cryopreservation of eggs at low temperatures. The eggs are stored frozen in liquid nitrogen tanks called egg banksfor an unlimited time without losing its physical and functional characteristics.

Therefore, the main advantage of oocyte vitrification is that it maintains the quality of the oocytes at all times until the woman decides to use them.

To be able to vitrify oocytes it is necessary for the woman to administer the hormonal medication that will cause several oocytes to mature at once, and thus be able to aspirate them directly from the ovary by means of follicular puncture.

The eggs obtained are then frozen using the vitrification method and stored in the egg bank indefinitely. When a woman wants to become a mother, she can then use to in vitro fertilization (IVF) with her frozen eggs.

How eggs are frozen

If you would like more information about this technique to preserve female fertility, you can read on in the following article: What is egg vitrification and what are its advantages?

Embryo cryopreservation

An alternative to egg vitrification, offered to heterosexual couples, is to freeze fertilized eggs when they have already begun to divide, i.e. to freeze the embryos.

The process of freezing embryos is similar to that of vitrification of eggs. The embryos are placed in a cryoprotective medium and placed in vitrification straws. The straws are then stored in an embryo bank, where they remain frozen in liquid nitrogen until they are used.

Embryo vitrification process

If you are interested in learning more about this particular technique, you can get more details here: What is embryo vitrification - when and how is it done.

Ovarian transposition

Ovarian transposition, also known as ovariopexy, is a method of preserving female fertility that prevents possible injury to the gonads in the event of cancer.

What is ovarian transposition?

This technique consists of moving the ovaries to another part of the body, with the aim of moving them away from the place where the radiotherapy is to be performed. Once the cancer treatment has been completed, the ovaries are returned to their original position.

Freezing of ovarian tissue

Freezing ovarian tissue is still an experimental technique. This method of preservation would be recommended for pre-pubertal girls diagnosed with cancer.

The procedure for freezing ovarian tissue involves a biopsy to remove small pieces of the cortex of the woman's ovaries, where the eggs develop as adults. It should be noted that the cortex of the ovaries of prepubertal girls contains the egg precursor cells.

Method to cryopreserve ovarian tissue

The extracted immature tissue is dissected into thin sheets and frozen in liquid nitrogen. Later, once the cancer is confirmed to be gone and adulthood is reached, these plates are self-transplanted into the ovary or another part of the body, such as the arm.

Fertility preservation for men

The preservation of male fertility is carried out by freezing sperm. However, there is another experimental technique, the freezing of testicular tissue. However this is not yet in common practice.

In any case, the seminal quality of men who are going to undergo cancer treatment may be altered. For this reason, it is important for them to know how they can preserve their fertility. In this way, men will have the possibility of becoming parents once the cancer is overcome.

Each of the options for preserving male fertility is detailed below.

Sperm freezing

When a man is undergoing anti-tumor treatment (radiation or chemotherapy), sperm freezing is the simplest option for preserving male fertility. Moreover, it is currently the only alternative available to preserve male reproductive function.

Other cases in which sperm freezing is indicated are the following:

• Patients who are having a vasectomy.
• Patients with poor sperm quality.
• Patients with difficulty in obtaining the sample.
• Sperm Donors
• Transsexuals.

When sperm freezing is recommended

No medication is required for the freezing and storage of semen. The man simply must collect a semen sample with a previous sexual abstinence of 3 to 5 days. Once the sample has been obtained, its quality will be analysed in the laboratory by means of a seminogram.

Finally, the semen is processed to obtain the best quality spermatozoa and then placed in straws. These are sealed and stored in a sperm bank. Frozen sperm samples will remain in storage until the man decides to have children.

Embryologist Antonio Alcaide tells us:

The limiting factor for freezing a sample is the quality of the sample, the quantity of spermatozoa and the number of spermatozoa that move.

Freezing of testicular tissue

Testicular tissue freezing is an experimental technique that is recommended in cases of young males who have not reached puberty, and therefore cannot freeze their semen.

Technique used for the freezing of testicular tissue

The process is similar to freezing ovarian tissue. It involves removing small fragments of the cortex of the seminiferous tubules of the testicles, where the germ cells of the sperm are located. This tissue is then frozen until it can be used.

What is the cost of fertility preservation

Prices vary depending on the treatment and complexity of the process. The simplest and least expensive technique is semen freezing, which costs between $1,000 to $1,200 on average.

Egg and embryo freezing is a more complex and laborious technique, so their cost is higher. Freezing embryos can cost $12,400, while freezing eggs costs about $11,900. In both cases, a process of hormonal stimulation is necessary, which is usually not included in the costs. Furthermore, an additional fee of $500 per year for storage is charged on average.

Video on fertility preservation

Michelle Emblenton, biochemist at inviTRA, us what fertility preservation is like in this video:

Well, there are two main areas in which to think about fertility preservation. The first is for cancer patients. The treatments for cancers (such as radiotherapy or chemotherapy) tend to be very aggressive and can affect, or perhaps, destroy, the precursor cells which produce sperm or indeed the eggs. This will obviously lead to problems in fertility. The idea is to take a sample of the eggs or the sperm and freeze them before the cancer treatment so that they can be used at a later date in an assisted reproduction treatment.

FAQs from users

Why is fertility preservation discouraged for older women?

Fertility preservation treatment is recommended for the following type of cases:

• Women with endometriosis, genetic or autoimmune diseases, or who are going to receive any chemotherapy or radiotherapy treatment.
• Patients with low ovarian reserve.
• Patients who are going to postpone childbearing.
• Patients with low ovarian reserve.
• Patients who are going to undergo ovarian surgery.

The most advisable age to perform fertility preservation is to do it before the age of 35, since from that age, the quality of the eggs decreases considerably. As a woman's age increases, the quantity and quality of eggs decreases rapidly, especially after the age of 38. Eggs from older women are more likely to have some genetic and chromosomal alteration. Therefore, women 40 years of age and older will have poorer oocyte quality and low ovarian reserve.

However, this depends on each patient, and each case must be reviewed individually, since there are older women (37-39) in whom this fertility preservation treatment can be beneficial.

Is it better to preserve eggs or embryos if I am over 35 years old?

Although the technique of oocyte vitrification has improved greatly in recent years, it still has some shortcomings and a percentage of cryopreserved oocytes may be lost upon devitrification. However, in the case of cryopreserved embryos, the possibility of losing them in devitrification is lower. Therefore, if we only look at the technical side, the answer to this question would be that it is better to cryopreserve embryos rather than oocytes.

But before making the decision to undergo IVF treatment in order to cryopreserve embryos, we must bear in mind that the objective of cryopreservation, in this situation that arises, is to postpone motherhood, and the woman or couple who wish to cryopreserve embryos must consider the possibility that their personal situation may change in the future.

In the case of couples, they must take into account that the embryos are affiliated to both parents, so that, in the event of a separation of the couple, the woman would not be able to dispose of them freely, having to obtain the consent of the man to use them, taking into account that the fruit of the gestation would be affiliated to him, that is to say, they would be his children.

In the case of single women who wish to preserve embryos generated with donated sperm, they should also consider the option of finding a partner in the future, in which case, unless they still maintain an adequate ovarian reserve, they would not be able to have biological children together.

In short, embryo cryopreservation is a technique with a better rate of results, but it is not free of future problems in the event that the woman's social conditions change when the time comes to use them.

Is there an age limit on egg freezing?

In principle, there is no age limit on egg freezing; a woman can decide to do it whenever she wants. However, one should consider preserving her fertility at a young age, as egg quality is better at this point. This, at the same time, translates into higher chances of getting pregnant in the future by means of IVF.

What are the risks of preserving fertility?

There is no risk involved in preserving fertility. Simply, what we are going to do is freeze eggs or freeze sperm, because fertility preservation can be for both the male and the female.

Sometimes it can be a little bit difficult to get eggs out. In a woman who has a lot of adhesions that are excessively thick, or whose ovaries are distant, or due to certain health conditions of the patient.

For preserving fertility in males, since it is with normal ejaculates, there is no difficulty at all. When we are going to preserve the fertility of a male who, perhaps, we need a testicular biopsy because he has no spermatozoa, then the risk of the surgical intervention is high.

Generally, these are very simple procedures, very easy to perform, and the professionals who perform them are very accustomed to them, and they will rarely have any type of complication.

How can you keep sperm alive outside the body?

The only possible way to do this is by means of sperm banking. Today's freezing methods allow us to store sperm and reach almost the same success rates as if it has not been frozen previously. Thanks to the cryoprotectants and ultra-rapid freezing methods used, sperm can be kept alive outside the body, without being damaged and with almost the same fertilization potential.

Can you freeze sperm and egg cells at home?

Reproductive cells cannot be stored at home. For egg and sperm cells to be available for later use, they have to be cryopreserved in special conditions. Moreover, in the case of egg freezing, surgery is necessary prior to storing the ova, so the woman has to visit an egg bank or fertility clinic.

How long does sperm last frozen?

Sperm can remain frozen indefinitely. The method used for sperm banking allows us to store the samples without causing any damage to them, and keeping their physical and functional properties almost intact.

Recommended reading

Throughout the article we have talked about freezing and vitrification. If you want to know the difference between these two terms, we recommend visiting the following article: What is gamete and embryo freezing and vitrification?

In addition, preserving fertility is very important for cancer patients in order to have children in the future. If you are interested in this topic, you can continue reading in the this post: Preserving fertility in women with cancer.