Unused embryos after in vitro fertilization

When a couple undergoes a reproductive IVF treatment, either by the traditional method or ICSI, doctors try to obtain the largest possible number of embryos, in order to increase the possibilities of success.

The Spanish assisted reproduction law 14/2006 allows for the transfer of a maximum of 3 embryos. The couple or single woman undergoing a reproductive treatment is the one who decides, after hearing the doctor’s advice, how many embryos will be transferred.

In this regard, it is important for the specialists in reproduction to inform the patient about the benefits, risks and effects of transferring one, two or three embryos depending on the characteristics of the woman and her specific medical situation.

Destination of unused embryos

Contrary to what some people think when they start the in vitro fertilization process, choosing the number of embryos that will be transferred is not the only important decision the patient has to make. After the transfer, the patients need to decide what to do with the embryos that weren’t transferred, that is to say, the so-called lefover embryos o unused embryos.

The legislation on assisted reproduction describes the possible options. In Spain, law 12/2006 states in article 3 that “unused pre-embryos of in vitro fertilization techniques, which are not transferred to the woman’s uterus during a reproductive cycle, may be cryopreserved and kept in authorized banks”.

The possible uses or destinations of these cryopreserved embryos are the following:

  • Own use.
  • Donation to other women or couples for reproductive purposes. This process is called “embryo adoption“.
  • Donation for investigation. The couple will be informed about the specific project their embryos are being used for.
  • Cessation of conservation.

The last point can only be performed when the woman has completed her reproductive stage, that is to say, by the time she is 50 years old or if she presents any malformation or a medical problem that prevents her from being pregnant. Furthermore, as stipulated by law, this should be corroborated by two medical specialists who have no connections to the center where the embryos are preserved.

Consent renewal

Once the clinic has explained in detail the four possible options, the woman or couple must sign an informed consent, authorizing the chosen destination. This consent must be renewed every two years.

The destination of the cryopreserved embryos can be changed. It is common for the first chosen destination to be cryopreservation for later use by the woman herself due to a failed first cycle of in vitro fertilization, or due to the desire to have another child. After several years, some patients decide to change the destination of their embryos.

If after two consecutive renewals, the reproductive center where the embryos are stored fails to attain the woman or couple’s signed consent and are able to demonstrate the actions taken to achieve renewal and the lack of response, the pre-embryos belong to the clinic. The clinic can decide what to do with the embryos, provided it follows the confidentiality and gratuity conditions.

Nowadays, it is estimated that only 40% of couples renew their consent. The vast majority of couples ignore their embryos mainly because they cannot cope with the financial obligations of conservation.

On the other hand, the donation of pre-embryos for adoption by other couples is the least preferred option. Only 4% of couples who renew their agreement decide to donate their embryos to other couples.