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Blastocyst transfer

What is blastocyst transfer?Patient talking to a doctor about  blastocyst transfer

Embryos can be cultured for up to six days, until they become blastocysts. At this stage it may be easier to select the best quality embryo(s).

With blastocyst transfer, embryos are cultured in the laboratory incubator to the blastocyst stage before they are transferred to the womb.

At this time, one or two of the best quality blastocysts are selected and then implanted into the woman’s womb. A blastocyst must successfully attach itself to the wall of the womb for a woman to become pregnant.

Is blastocyst transfer for me?

Many clinics are now offering blastocyst transfer as a means of improving chances of pregnancy after single embryo transfer.

This is particularly useful for younger women with a good prognosis for pregnancy from IVF.

Your doctor may also suggest you try blastocyst transfer if you have produced good quality embryos in a previous IVF cycle but they failed to implant in the womb.

It is not normally recommended if you produce fewer than normal healthy eggs.

As with embryo transfer, due to the risks of a multiple birth, you may want to consider single blastocyst transfer. Indeed, your clinic may encourage you to have only one transferred.

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How does blastocyst transfer work?

The procedure for blastocyst transfer is similar to that for normal embryo transfer, but instead of being implanted into the womb after two or three days, the embryos are allowed to develop for five to six days before transfer.

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What are the risks of blastocyst transfer?

Not all embryos will develop to produce blastocysts in the laboratory. Embryos can stop developing at the four-cell stage (day two) and progress no further.

The embryologist may advise your consultant that in your case it is safer to consider a day two-three embryo transfer than risk having no blastocyst to transfer on day five-six.

As with normal embryo transfer, due to the risks of a multiple birth if more than one blastocyst is transferred, you may want to consider single blastocyst transfer.

For more information on the problems involved in multiple births, speak to your clinician and see the following information:

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What are my chances of having a baby with blastocyst transfer

Female fertility diminishes with age, so if you are using your own eggs, on average, the younger you are, the higher your chances of success.

In the year from 01/01/2008 - 31/12/2008, for women receiving stimulated IVF using fresh blastocysts created with their own eggs, the percentage of cycles reaching blastocyst transfer that resulted in a live birth was:

  • 47.9% (325/679) for women aged under 35
  • 44.6% (190/426) for women aged between 35-37
  • 34.1% (79/232) for women aged between 38-39
  • 26.8% (60/224) for women aged between 40-42
  • ** (1/33) for women aged between 43-44
  • **(0/2) for women aged over 44

** Percentages are not calculated where there are less than 50 cycles reaching blastocyst transfer. Figures given in brackets are (cycles resulting in a live birth / all cycles reaching blastocyst transfer).

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Page last updated: 07 January 2015

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Understanding success rates

Question markWhen choosing a clinic, the statistics should not be the only thing to consider.

Make sure you know what clinical success rates mean before you start analysing them.


...more about success rates