Handling of embryos from in vitro fertilisation

With in vitro fertilisation (IVF), embryos are produced outside the body. The charts below show how many embryos are produced in Switzerland and what types of genetic testing are performed.

If a couple decides to pursue in vitro fertilisation (IVF), the treatment cycle begins with hormone stimulation in the woman. This is designed to promote the maturation of oocytes. The mature oocytes are then retrieved and combined with sperm cells. In Switzerland, a maximum of twelve embryos may be produced in this way within a treatment cycle.

After embryos have been produced in vitro, the procedure may be continued in various ways. By means of PGD (preimplantation genetic diagnosis) the embryos can be tested for a specific genetic defect (preimplantation genetic testing for monogenetic disorders or PGT-M) or for a specific structural chromosomal disorder (preimplantation genetic testing for structural rearrangements or PGT-SR). Finally, embryos can also be tested for spontaneously occurring numerical chromosomal disorders (preimplantation genetic testing for aneuploidy or PGT-A). If there is no need to test the embryos they can also be transferred directly to the woman’s uterus. The attempt to establish a pregnancy may also be deferred. In this case, the embryos are cryopreserved. Ideally, to avoid multiple pregnancies, only one embryo will be transferred. The other embryos may be cryopreserved. The couple may, however, also decide to have their embryos destroyed. Such a decision may be due to failure of embryo development, the presence of a genetic or chromosomal disorder, or a desire not to proceed with assisted reproduction. Surplus embryos can also be made available for research.

The following charts show how many embryos undergo each of the various processes.

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In 2017, under the revised Reproductive Medicine Act, it became possible to test embryos for a genetic disorder in Switzerland. Accordingly, up to 2016, no data is available concerning the reason “genetic disorder”.

Essentially, it is always up to the couple to decide what happens to an embryo. The couple also have the option of discarding an embryo in the absence of medical reasons. In the chart, this is recorded as “Couple’s decision”.

If one of the parents dies, no further use may be made of an embryo. The couple or one parent may also revoke consent for embryo preservation. In addition, preservation is limited to a maximum period of ten years. In the chart, these reasons for the destruction of embryos are recorded as “Other reasons”.

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