Accessibility tools
Cambridge IVF logo

Embryo transfer

Embryo transfer is the process by which we pass a narrow catheter through your cervix to place one or two embryos resulting from your IVF or ICSI treatment into your uterus to allow implantation to occur.

We will have selected the best quality embryo(s) with the highest chances of producing a viable pregnancy. If there are any remaining good quality embryos, we will freeze them so that you can use them in the future if you wish to. Check our sections on frozen embryo transfer and embryo freezing for more information.

During your fertility treatment and before we perform your embryo transfer, we will talk about the following things with you:

  • Is it suitable to transfer on Day 5 after an extended embryo culture?
  • Would an elective embryo transfer (eSET) be beneficial for you?

Not every case is the same. For that reason, we will adapt to your particular situation to make the best decision for your embryo transfer. We are committed to give you the highest chances of having a baby.

Transfer on Day 3 or 5?

Advice according to the HFEA: "In the UK, roughly three quarters of women have a blastocyst transfer (Day 5) and a quarter have a cleavage stage transfer (Day 3)."

In our lab, we aim to culture embryos for a longer period of time and transfer them on Day 5 whenever possible. Here are the main reasons:

  • It is safe to keep embryos for that long in culture. Currently available embryo culture techniques are well established and simulate the natural environment to allow blastocyst formation.
  • Extended culture provides more information about the development. We can detect those embryos who, despite being good quality on Day 3, do not follow a correct development or arrest afterwards. Therefore, we can potentially do a better embryo selection and have higher live rates per embryo transfer. Check here for our success rates.
  • Embryos that develop to blastocysts on Day 5 are more likely to result in a pregnancy as they have undergone essential gene activation, cell specialisation and differentiation.
  • Day 5 is the moment in which the embryo would naturally enter the uterus. For implantation, the embryo needs to be on blastocyst stage.

It is important to know that not all the embryos will reach the blastocyst stage. Around 30-50% of embryos will survive till this point of development. Because of this, an extended culture and transfer on Day 5 is not suitable for everyone.

If you have a low number of embryos on your IVF or ICSI cycle, it may be likely that very few or none make it to Day 5 and we will consider a transfer on Day 3. We will always discuss this with you during your treatment cycle.

Elective Single Embryo Transfer (eSET)

An elective single embryo transfer (eSET) is the transfer of only one embryo when there are multiple good quality embryos available for transfer in an IVF or ICSI cycle. Do not worry, eSETs do not reduce success rates. The objective is to have the best chances of a pregnancy whilst reducing the chances of it being multiple one.

You need to take into account that even if we only transfer one embryo there is still a small probability of having a multiple pregnancy. This comes from the rare possibility of the embryo dividing to form twins. According to the HFEA, there is 1-2% risk of a multiple pregnancy with a single embryo transfer.

Although the prospect of a twin pregnancy may sound attractive, it is important to be aware of the risks to the developing children (miscarriage, prematurity, birth defects etc) to yourself (high blood pressure, gestational diabetes, anaemia etc) and the long term effects that it could have on you and your family.

We take our commitment to reduce unnecessary multiple births very seriously. With this in mind we look very closely at whether it’s appropriate for us to transfer one (eSET) or two embryos. We will calculate this based on your age, treatment history and the quality of you embryos or blastocysts. We’ll always inform you what we believe to be the best strategy for you at the time of your embryo transfer. Please do not hesitate to ask us any questions you may have.

Frozen Embryo Transfer

There are a few cases in which you can do a frozen embryo transfer.

  • If you opted to have our elective Freeze All Embryo option
  • If you had surplus embryos frozen from your previous fresh IVF/ICSI cycle
  • If you froze your embryos for medical reasons or fertility preservation.

In each case, we can thaw them one at a time and place them in your uterus exactly as we would in a fresh cycle to try to establish a pregnancy.

What should I expect on the day?

You should bring your partner or a friend with you as we would prefer you to have someone with you and to someone to take you home after the procedure. Please be aware that there may be certain restrictions in place due to Covid-19. Please check before your transfer if this is the case.

We will confirm with you the number of embryos we are transferring and let you know the quality. We will then ask you to sign the consent prior to the embryo transfer taking place. You also have the option of seeing the embryos on the screen before we transfer them if you would like.

Then, you will lay down and one of our embryologists will bring the catheter containing the embryo(s) to be transferred. Our specialist fertility clinician will introduce the catheter through your cervix and place the embryo(s) at the fundus of the uterus using an ultrasound to guide him/her.

Finally the embryologist will take the catheter back to the lab to check that the catheter is clean, confirming that the embryo(s) has been correctly introduced into your uterus and the catheter is empty. If any embryo is found on the catheter, the process will be repeated.

What should I do after?

You do not need to rest after the transfer. Lying on your back for days afterwards will not help the embryo(s) implant and in truth may do more harm than good. We recommend you take things easy, no strenuous exercise or horse riding, but just try to carry on with your life as normal otherwise.

You can have your pregnancy test on the date established by your consultant. This is usually done 15 days after your transfer.

If you would like more information, please at enquiries@cambridgeivf.org.uk or on 01223 349010.