Blastocyst: Transference, Disadvantages, Twins and Key Points

It is a human embryo that has five, six or seven days.

Until relatively recently, day 3 embryos were routinely transferred to the uterus during in vitro fertilization (IVF) treatment.

Most doctors now believe that the transfer of better-developed embryos, that is, those that have reached the blastocyst stage, makes pregnancy more likely.

Under the microscope, a blastocyst is markedly different from an embryo on day 3. There is a cavity filled with fluid in the middle called blastocoel. Another area, which houses a dense collection of cells, is called the internal cell mass and will become the fetus.

A third assortment of cells, near the central cavity, will form the placenta.

Blastocyst transfer

Each patient is different. But the consensus is that an embryo that survives for five days or more, particularly one of high degree, is probably more viable for implantation.

Many younger embryos do not develop until five days and their future is more difficult to assess. Therefore, blastocyst transfers are, in general, more likely to be successful than transfers using younger embryos.

The transfer of blastocysts can make things easier for implantation. In reproduction without IVF, a day 2 embryo (which usually comprises four cells) will continue to roll down the fallopian tube into the uterus.

Putting a blastocyst directly into the uterus on day five or six is ​​an easier prospect for the now highly receptive uterus. In addition, genetic tests such as PGD are carried out more precisely in blastocysts.

Why do not all patients with IVF use blastocysts and abandon day 3 transfers?

You may not get there. Depending on factors such as your medical history, age, and the quantity and quality of embryos created in your IVF cycle, your doctor may feel it is safer to transfer a younger embryo.

Do blastocysts lead to more pregnancies with IVF?

In certain groups of women yes. If you are less than 35 years old, statistics indicate that live birth rates after blastocyst transfer are higher.

Data from the clinic in the United Kingdom and throughout Europe show that blastocyst transfers are on the rise. See the latest report of the HFEA.

Disadvantages with blastocyst transfers

One disadvantage is that you may have less or no surplus embryos to freeze. Frequently, patients with IVF tactically ignore embryo freezing for a second attempt.

The fact is that frozen embryo transfers, particularly those that use blastocysts, are having more success.

If you have two blast cells, freezing one and transferring the other can be sensible for certain patients. In addition, not all clinics perform blastocyst cultures. And those who do will probably charge you for it.

Some clinics do it more skillfully than others, quality control and correct culture techniques are essential. Inspect your clinic’s facilities and insist on seeing your blastocyst success rates.

Transfer a blastocyst or two?

Hot topic. Recent research on the selective transfer of single blastocyst indicates that the probability of a live birth of a transferred blastocyst is practically the same as for two.

But another study said that this only applies to younger women and when the first cycle uses fresh embryos and the second uses frozen. However, 34% of the younger women who had two transferred blastocysts ended up with twins.

Only 7% had twins from a single blastocyst transfer. So, multiple pregnancies are a continuing concern.

If you choose to have your in vitro fertilization outside of your country, and you have several cultured blastocysts, you have the final word on how many to transfer (although two is usually the maximum).

Twins after a single transfer of blastocysts … what’s happening?

The blastocysts can be divided, usually after the transfer. Identical twins are not uncommon.

Many couples can live with that. The most dramatic scenario is whether both blastocysts divide and progress to live births. Quadrupeds, anyone? (This is very extrange)

So, blastocysts are a good thing or not?

The key point about blastocysts is that multiple births are less common than with younger transfers. The transfer of a good quality blastocyst is often recommended.

That said, the single-embryo unit has recently been diluted in the UK following a court ruling that effectively supports older patients with IVF to transfer two.

In the past, clinics could transfer up to four day 3 embryos and hope for the best. Blastocysts allow more informed choices and better control of results.