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Since 1st September 2017, up to 12 fertilized eggs can be developed and observed for 5 days after fertilization (blastocyst stage) outside the body.

Why is this beneficial for family planning?

Egg genes (commonly referred to as hereditary traits) are primarily responsible for the embryo’s development up to the third day after fertilization.


As of the third day after fertilization occurs, the embryo’s genes (the father and mother’s hereditary traits) are collectively responsible for their growth. And as of the fifth day after fertilization, embryonic cells are no longer identical: one can recognize cells which form the embryo itself and cells that form the placenta (blastocyst stage).

On average, 6 out of 10 fertilized eggs are healthy enough to develop into blastocysts 5 days after fertilization. Switzerland’s previous laws allowed only a maximum of 3 fertilized eggs to develop outside the body up to 5 days, like in Germany presently.

The newer Swiss laws now allow for the observation of up to 12 embryos, and thus permits for a higher number of embryos with maximum potential for pregnancy to be chosen and transferred.  The criteria to choose from are the morphology of the embryo and the dynamics of the development of the embryo. 

How can this impact pregnancies? 

  • The probability of pregnancy increases after an embryo transfer of one or several blastocytes. At the Fertility Clinic Basel, we have doubled the probabilities of pregnancy after the embryo transfer; couples are less likely receive a negative pregnancy test after 10 days. 

  • There is a greater probability of having twins when inserting 2 embryos. Through development of multiple embryos, a singular embryo with good chances may be chosen. Thereby, the probability of getting pregnant remains high and the risk of having children from multiple births is reduced.

  • It may be possible that a couple may not have an embryo transfer in the case that no embryo develops into the blastocyst stage. In such cases, we will discuss how to proceed with family planning and possible options with the couple. 

Keep in mind…

  • It is widely accepted that the development of blastocytes outside the body does not negatively impact a future child’s health.

  • The 5-day-development outside the body does not guarantee that embryos have a longer lifespan. 

  • Natural selection takes place outside the body, so that non-viable embryos are less likely to be transferred.

Who is suitable for this treatment ?

The majority of couples.

What is the cost of this treatment?

The costs of in vitro fertilization are not covered by the Swiss health insurance. If applicable (cantonal and individual differences), one can claim financial expenses to reduce the income tax. German health insurance often covers half the cost of the treatment.

The usual cost for a therapeutic cycle is 7200 Swiss Francs and includes medication and the development of 12 fertilized eggs during 5 days followed by an embryo transfer. This cost does not include the cryopreservation of additional blastocysts. Depending on the number of embryos, one must incur additional expenses of ca. 400 Swiss Francs per therapeutic cycle.


Day 1: Fertilized egg


Day 2: 4 Embryonic cell


Day 3: 8 Embryonic cell


Day 5: Blastocyst

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