Embyo bank

Sterile couples where the man cannot provide sperm and the woman cannot provide an egg have the option of using an Embryo Bank. The woman needs to have a uterus capable of carrying a pregnancy.

The embryos come from donor eggs that have been fertilised with sperm from an anonymous donor at a Sperm Bank. The embryos obtained with donor eggs and sperm from the Sperm Bank can be transferred fresh (without being frozen), or they can be frozen. The embryos are unfrozen when they are going to be transferred. Frequently, depending on the response of the donor’s ovaries, sufficient embryos are obtained for two transfers. The results are between a 55 and 65% chance of pregnancy.

Another possibility is that the embryos come from couples who have gone through in vitro fertilisation (IVF), have had the children they wanted and now wish to donate their surplus frozen embryos.

Embryos are frozen when a greater number of embryos are obtained than needs to be transferred, from 1 to 3, depending on the couple’s wishes. Spanish law prohibits the transfer of more than three embryos. In the case of patients’ embryos, frozen embryos are always used, which allows a transfer to be made with a 40% chance of pregnancy.