Questions relating to surplus embryos

The following section defines concepts relating to surplus embryos in a readily understandable and legally binding manner. This is because the careful handling of research material in accordance with legal requirements is crucial in stem cell research.

The following eleven questions on surplus embryos clearly differentiate and explain the central legal definitions related to the topic. The information is primarily intended for scientists working in this research area.

What are surplus embryos?

Surplus embryos are embryos that are produced in the course of an in vitro fertilisation (IVF) procedure but cannot be used to establish a pregnancy and therefore have no prospect of survival (Article 2 Letter b StRA).

How can embryos become surplus?

• The embryo's potential for development is limited or non-existent.
• As a result of illness or an accident, the embryo cannot be transferred to the woman concerned.
• For personal reasons, the woman concerned does not wish to have the embryo transferred to her uterus.
• The woman concerned dies

What are “old law” surplus embryos?

Old law surplus embryos are embryos that were produced and cryopreserved before the Federal Act on Medically Assisted Reproduction (Reproductive Medicine Act, RMA) came into force on 1 January 2001.

What are “new law” surplus embryos?

New law surplus embryos are embryos that were produced and became surplus after the Reproductive Medicine Act came into force on 1 January 2001.

What is the difference between an inseminated oocyte and an embryo?

We talk about inseminated oocytes once the sperm has penetrated the ovum but before the male and female pronuclei have fused. The inseminated oocyte with the two visible pronuclei arises about 5 hours after insemination and lasts until about 20 hours after insemination. At this stage, the paternal and maternal sets of chromosomes are still physically separate. Under the Reproductive Medicine Act, an embryo is formed once the male and female pronuclei have fused, i.e. around 24 hours after the sperm penetrates the ovum. The embryonic phase ends when organogenesis is complete, about 8 weeks after fertilisation.

What is the difference between a zygote and an embryo?

A zygote is the first cell of an embryo. It comes into existence after the two pronuclei have fused, around 23 hours after insemination. A zygote is therefore already an embryo, as defined in the Reproductive Medicine Act.
The zygotic stage ends as soon as the first cell division occurs, and the early-stage embryo consists of 2 cells. This occurs around 24-28 hours after insemination. In medical practice, these terms are not always used consistently. In reproductive medicine, for example, the term "zygote" is frequently used as a synonym for "inseminated oocyte". In practice, the term "embryo" is frequently only applied from the 2-cell stage onwards.
For legal purposes, however, only the legal definitions are relevant. According to these definitions, embryos and zygotes are not allowed to be cryopreserved in Switzerland, while the storage of inseminated oocytes is permissible.

How many surplus embryos arise per year?

A statistical survey conducted on a single occasion by the FOPH indicated that approx. 700 surplus embryos were created in Switzerland in 2003. Figures for 2005 and 2006 were compiled by the Federal Statistical Office. According to these figures, a total of 1421 surplus embryos were created in 2005 and 1138 in 2006.

Is it permissible to store “new law” surplus embryos?

The Reproductive Medicine Act prohibits the storage of embryos (Art. 17, paragraph 3 RMA). However, this prohibition applies solely to the context of medically assisted reproduction, not to cryopreservation for stem cell research. As soon as embryos become surplus in the course of an IVF procedure, the reproduction procedure ends and Article 17 paragraph 3 RMA ceases to apply.

If surplus embryos are stored for research, the Stem Cell Research Act (StRA) applies. This allows IVF clinics to store embryos, if a licence for storage (cryopreservation) has been granted by the FOPH in accordance with Article 10 StRA). A licence for storage is granted if:

1. The FOPH has already licensed a derivation project (under Art. 7 or Art. 8 StRA),
2. Storage is essential (written explanation required),
3. The technical and operational requirements are met.

Accordingly, it is permissible for in-vitro fertilisation (IVF) clinics to store surplus embryos under the stated conditions with a view to carrying out research (see also the Federal Council's Report of 20 November 2002 on the Federal Act on Research Involving Surplus Embryos and Embryonic Stem Cells, BBl 2003, p. 1251).

Application forms for cryopreservation can be found here:
 “Projects for the derivation of human embryonic stem cell lines involving prior cryopreservation of surplus embryos”

Interner Link zu “Projects aimed at improving derivation methods, using cryopreserved surplus embryos”

How long can “old law” surplus embryos be stored for?

Old law surplus embryos can be stored for purposes of research until 31 December 2008 (Art. 42 Para. 2 RMA).

For what purposes can surplus embryos be used?

If written consent is available from the couple concerned, surplus embryos can be used for research purposes. However, surplus embryos can only be used for projects aimed at deriving stem cells or improving derivation methods. Research undertaken for other purposes (e.g. pure developmental biology research) is not permissible.

How can scientists gain access to surplus embryos?

There is no centralised procedure for the allocation of surplus embryos for stem cell research. Scientists therefore need to contact IVF clinics themselves and provide physicians with information sheets and consent forms.

Last modification 17.08.2018