Which patients are suitable for single embryo transfer (SET)?

Whether or not the transfer of only one embryo is right for a particular patient depends on their prognosis. Women with the best chance of pregnancy following IVF are also at highest risk of conceiving twins.

The criteria for eSET are based on clinical evidence, and therefore patients should be treated in the same way, irrespective of whether they are privately or NHS funded.

The British Fertility Society (BFS) and the Association of Clinical Embryologists (ACE) updated their professional guidelines on elective single embryo transfer (eSET) in 2015. These guidelines can be found on the website of the journal, Human Fertility.

What are the relevant factors?

The factors that have been identified as being relevant are:

  • female age
  • obstetric and gynaecological history
  • number of previous failed IVF attempts
  • woman’s ovarian reserve/previous response to stimulation
  • number and quality of embryos available (including blastocysts).

Each of these factors, alone or in combination, are relevant in determining the overall prognosis for a patient and therefore, whether eSET is appropriate for them.

The importance of the overall prognosis

eSET is not just for younger women. Figures from the HFEA’s report, Improving outcomes for fertility patients: multiple births 2015, show that the multiple birth rate for patients over 37 ranges from 28-16% when two blastocysts are transferred. When eSET is used this drops to approximately 2.5%. However, the pregnancy rates remain comparable between patients treated with eSET and DET across all ages.

The number of previous failed IVF attempts is relevant when targeting the right patients for eSET because the risk of having a twin birth from a double embryo transfer is reduced when you’ve already had two or three cycles of IVF. This means that eSET is normally only used for the first one or two IVF cycles, after which clinics can revert to double embryo transfers.

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Advising patients about SET

The Infertility Newtowk UK have published a factsheet explaining why and how fertility clinics should be advising their patients to have a single embryo transfer (SET).

Download the factsheet (305 KB)

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What other countries are doing

Many other countries have already successfully introduced a single embryo transfer policy – the multiple birth rate has plummeted while birth rates have remained largely unaffected.

Find out more>>