Fate of the embryos left over from an 'in vitro'

In most cycles of in vitro fertilization (IVF), either with own ovum or ovodonation, there are surplus embryos at the end of treatment. The fate of frozen embryos depends on both the legislation regulating assisted reproduction techniques in Spain (Law 14/2006) and the decision of the partner or patient. In this article we tell you the possible destinations in each situation.

Next you have an index with all the points that we are going to treat in this article.

Index

Fate of embryos left over from in vitro fertilization

1. What is the origin of the surplus embryos?
2. Fate of frozen human embryos
3. Renewal of consent
3.1. What about the abandoned embryos in Spain?
4. Questions of users
4.1. If artificial insemination is performed instead of in vitro fertilization, are there also surplus embryos?
4.2. Do you get better results with a second IVF than with the transfer of frozen embryos?
5. Recommended Reading

What is the origin of the surplus embryos?

When a couple undergoes a reproductive in vitro fertilization treatment, both by the traditional method and spermatozoid sperm microinjection (ICSI), an attempt is made to obtain as many embryos as possible in order to increase the chances of success of the cycle.

However, it is not possible to transfer all the embryos obtained mainly due to two factors:

Try to avoid multiple pregnancy, so a single embryo will be transferred whenever possible, that is, without compromising the chances of success.
The Spanish law on techniques of assisted human reproduction (Law 14/2006) allows the transfer of a maximum of 3 embryos.

The couple or single woman who undergoes the reproductive treatment is the one that decides, along with the medical recommendations of the specialists, the number of embryos that wishes to transfer. Currently, the most common is that one or two embryos are transferred. Only in cases with poor prognosis are three transferred.

In this regard, it is important that assisted reproduction professionals report on the advantages, risks and effects of transferring one, two or three embryos according to the characteristics of the woman and the specific medical situation.

On the other hand, it should be noted that the optimization of the embryo freezing techniques that has taken place in recent years makes it possible to cryopreserve the surviving embryos without compromising their survival rates. In addition, the quality of treatments and embryo selection techniques has also increased.

If you are thinking of transferring cryopreserved embryos, we recommend that you access the following link: Discounts in assisted reproduction clinics for the transfer of frozen embryos. You will find cheaper prices for your treatment.

All these advances allow more transfers of a single embryo without decreasing pregnancy rates per cycle of ovarian stimulation and, in turn, make the number of surplus embryos is increasing.

Fate of frozen human embryos

Contrary to what is believed at the beginning of the in vitro fertilization process, the choice of the number of embryos to be transferred is not the last important decision that the woman or couple undergoing treatment should take. After transfer, you must decide what to do with untransferred embryos.

In Spain, cryopreservation of embryos is regulated by Article 11 of Law 14/2006. Among other things, it states:

The remaining pre-embryos of the application of in vitro fertilization techniques that are not transferred to the woman in a reproductive cycle, may be cryopreserved in the authorized banks for this.

This Act also specifies the options that exist for the destination of frozen surplus embryos. Here are the possible uses for these cryopreserved embryos:

Own use, either because the first attempt failed or because a second child is desired. This option allows another embryo transfer without the need to revert to ovarian stimulation or follicular puncture, the most annoying stages of in vitro fertilization treatments.
Donation to other women or couples for reproductive purposes. In this case, patients must comply with a number of requirements for the donation, such as the woman is not more than 35 years old at the time of treatment or who are not carriers of hereditary diseases. The receiving couple will perform what is known as an embryo adoption.
Donation for research purposes. The couple will be informed of the specific project for which their embryos will be used and must sign a specific consent stating the project in question.
Cessation of conservation.

The last option can only be made when the woman has finished her reproductive period, that is, when she is approximately 45-50 years of age or presents some malformation or medical problem that incapacitates her to complete the pregnancy. In addition, as stipulated by the Law, this must be corroborated by two specialist doctors outside the center in which the embryos are preserved.

Possible destinations for IVF surplus embryos

Renewal of consent

Once the center has explained in detail the four possible options to the woman or couple, the parent must sign an informed consent by which authorizes the chosen destination. This consent must be renewed every one or two years.

At each renewal, the destination of the cryopreserved embryos can be modified. It is common that the first destination chosen is cryopreservation for the later use of the woman or couple, either because of failure of the first cycle of in vitro fertilization, or because of wanting to give a brother to the child already born, and yet, after several years, discard these options and decide to change the destination.

Currently it is estimated that only 40% of couples renew their consent. The vast majority of couples disregard their embryos, mainly for not taking care of the economic obligations of conservation.

On the other hand, the donation of the pre-embryos for the adoption of the same ones by other pairs is the option less chosen: only 4% of those who renew the consent decides to donate them to other pairs.

What about the abandoned embryos in Spain?

One of the problems currently experienced by assisted reproduction clinics is that most patients with frozen embryos do not renew their consent, so they do not communicate that they wish to continue with the maintenance of these cryopreserved preembryos nor indicate a new destination. This means that many embryos are left on the banks of assisted reproduction centers.

In the event that after two consecutive renewals the reproductive center where the embryos are stored fails to obtain the consent of the woman or the couple, and is able to demonstrate the actions taken to achieve the renewal and the absence of response, the pre-embryos will be available to the clinic.

Abandoned embryos are available to the clinic

Therefore, if patients do not renew consent, the clinic may choose the destination of the abandoned embryos, provided that it maintains the conditions of confidentiality and gratuity.

User questions

If artificial insemination is performed instead of in vitro fertilization, are there also surplus embryos?

No. In assisted reproduction treatments in which artificial insemination is performed, fertilization occurs in the woman's uterus. Therefore, neither the eggs are extracted nor embryos are generated in the laboratory.

Do you get better results with a second IVF than with the transfer of frozen embryos?

One of the factors that most influences the results of in vitro fertilization (IVF) treatments is the quality of the embryos.

Thanks to advances in cryopreservation, we can now vitrify (freeze) the embryos without altering their quality.

Therefore, if the embryos are of good quality, the results of vitrified embryo transfer (ETV) are practically the same as if we transferred fresh embryos from a second ovarian stimulation.

However, it should be noted that for the patient it is much more convenient to transfer frozen embryos than to have to go through ovarian stimulation and follicular puncture again. Therefore, the most common is to transfer all the cryopreserved embryos before beginning another cycle of ovarian stimulation.

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