What is it about?

Cryo-transfer is a technique in which a previously vitrified embryo is transferred to the patient. These embryos come from previous IVF or ICSI cycles in which good quality embryos were left over or in which the transfer was postponed, or they are donated embryos.

Who is it for?

  • Couples that have vitrified embryos from previous cycles
  • Couples who resort to embryo donation


endometrial preparation

As in a cycle with fresh embryos, the patient must undergo an estrogen-based endometrial preparation treatment so that the endometrium presents the appropriate thickness on the day of transfer.

Desvitrification of the embryo

Embryos of good quality from previous treatments remain preserved in liquid nitrogen tanks, at a temperature of -196º C, which allows their qualities to remain intact.


A few hours after thawing, the embryo is transferred to the patient’s uterus. This process is performed following the same procedure as with fresh embryos, so it is completely painless and does not require the patient to be sedated.


Several days after the transfer, a blood test is performed to determine the value of this hormone to control pregnancy.


  • What is the name and what does the freezing technique consist of?
    • The process is known as vitrification and it is a technique that combines rapid cooling rates with high concentrations of cryoprotectant, making better survival rates possible and the subsequent implantation of embryos.
  • Why are pregnancy rates with cryotransfer sometimes better than those with fresh embryos?
    • The hormonal environment in the uterus is very important and it has been seen that sometimes it can affect the uterine implantation. This is the reason why in certain cases it is decided to postpone the fresh transfer and make a cryotransfer.
  • Do children born by cryotransfer have a higher risk associated with having a disorder?
    • According to various studies, children born by this technique do not present greater risks compared to fresh transfers.
Check our rates

he success rates shown correspond to those of our headquarters in Marbella. The percentages presented in this section have been divided as follows:

eta-hCG positive: hormone produced by the body once the embryo is implanted in the uterus. Calculated after 10/12 days after embryo transfer.

Clinical Pregnancy: Calculated in the 4 week gestation by means of ultrasound. Its presence is a sign of implantation of the embryo in the endometrium.

SEF (Spanish Fertility Society). The rates shown here correspond to the last report published by the agency in 2016.