Blastocyst transfer

Embryo transfer

With this treatment, embryos are allowed to develop to the blastocyst stage before being transferred to the womb

During IVF, eggs are removed from the ovaries and mixed with sperm in a laboratory so that fertilisation can occur. The embryos are then left to develop in the laboratory.

When the Lister Fertility Clinic first opened in 1988, embryos were routinely transferred back into the womb two to three days after egg collection. We now have the expertise to grow embryos to five to six days after egg collection, when the pre-implantation embryos are called blastocysts.

Advantages over early transfer

1: Improved pregnancy outcome

The genetic make-up of embryos becomes more apparent after Day 3 of development so by waiting to Day 5, we are better able to select the most suitable embryos for transfer.

The table below and related chart to the right show how livebirth rate at every age-group is improved when blastocysts are available for transfer.

Chart from LFC for Blastocyst

Blastocyst transfer All Couples
Blastocyst transfer all couples

2: Minimises multiple pregnancy rate

By waiting to Day 5 we can assess embryo quality more accurately and better advise couples of the suitability of embryos for freezing and how many embryos may be best to transfer. Patients under the age of 40 can legally have no more than 2 embryos transferred and patients 40 or over no more than 3. Younger women with high quality blastocyst embryos available for transfer are advised to transfer only 1 embryo as this does not compromise pregnancy outcome, minimises multiple pregnancy rate and any extra embryos can be frozen.

3: Physiological timing of transfer

During natural conception, eggs and sperm fertilise in the fallopian tube, in which they continue to divide and only reach the uterus on Day 5 post fertilization at this blastocyst stage. Therefore a Day 5 transfer mirrors this physiological timing.

4: Confirms embryo quality before freezing

We would only recommend freezing of supernumerary embryos at this stage as if embryos do not reach blastocyst stage by Day 5-6 they will not have the potential to achieve a pregnancy. Similarly, we would only recommend freezing top quality blastocysts to ensure a high chance of surviving the freeze/thaw process (>90%).

Our locations

From complex fertility treatment to diagnostic tests and procedures, we provide exceptional fertility care across our network of hospitals, outpatient centres and specialist clinics.

Get in touch

If you want to book an appointment with one of our fertility specialists, or if you have any questions about how we can help, please don’t hesitate to get in touch. 

You can also book an appointment at one of our fertility clinics. Simply click the links below, or call our team on: 020 7881 2000


Request an appointment at Lister Fertility Clinic, Chelsea

Request an appointment at Lister Fertility Clinic, The Portland Hospital

This content is intended for general information only and does not replace the need for personal advice from a qualified health professional.
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