Why should I recommend single embryo transfer (SET)?

eSET is now recognised as best clinical practice and should be considered the norm for the following reasons:

  • multiple pregnancy and birth are associated with greater risks to both mother and child (see What are the risks?)
  • the success rates of single embryo transfers when performed in selected patients are comparable to multiple embryo transfer
  • the incidence of embryos dividing to give monozygotic (identical) twins is higher with IVF, particularly in association with blastocyst transfer
  • multiple pregnancies cost significantly more than singleton pregnancies, particularly if babies are born prematurely, which has a significant impact on health and social services resources

Fertility treatments and multiple birth rates

In 2013, the Human Fertilisation and Embryology Authority (HFEA) register reported a 17% rate of multiple births after IVF. This is around 11 times higher than would be expected after natural conception.

Effect of elective single embryo transfer (eSET) on live birth rates

In countries where SET is used widely, experience has shown that when applied to selected patients, and followed by treatment using frozen embryos, eSET has little effect on the live birth rate compared to multiple embryo transfer.

In the UK, the percentage of elective single embryo transfers rose from under 5% in 2008 to almost 25% in June 2014. Over the same period, the multiple birth rate reduced from approximately 25% to 16%, whilst maintaining a live birth rate (per cycle started) of 25%.

Data from 2013 shows that for patients under 37, the cumulative pregnancy rate of fresh eSET followed by single frozen embryo transfer (FET) was 49% compared to a pregnancy rate of 40% after double embryo transfer.

These figures demonstrate that eSET is very effective. It reduces the multiple birth rate, avoiding the many associated risks to mothers, children and families and reducing the economic burden on health and social services, while maintaining healthy live birth rates.

We’ve already reduced the multiple birth rate significantly in the UK. We now need to continue to increase the implementation of eSET in appropriate patients, working towards the HFEA’s 10% target and ensuring that as many patients as possible achieve the best outcome: a single, healthy baby.

The experts say...

“By focussing on embryo selection methodology and running an effective cryopreservation programme single embryo transfer can become the norm for clinical practice without compromising success.”

Rachel Cutting, MBE, Principal Embryologist, Jessop Fertility

Did you know?

Although in vitro fertilisation (IVF) births account for only a small percentage (2.2%) of all births nationally, over 23% of all multiple births are IVF births. This means that IVF births contribute a disproportionately large number of multiple births to the overall rate.

Find out more about research into the impact of eSET and IVF outcome>>>