Day 5 Embryo Transfer
Blastocyst Transfer For IVF

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Day 5 Embryo Transfer: IVF


What Is Blastocyst Transfer?
What Are The Benefits Of Blastocyst Transfer?
What Is The Procedure?
What Are The Success Rates?
Who Is Most Likely To Benefit From It?
What Problems Can It Cause?
How Much Does It Cost?
Personal Stories

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IVF Guide
What Is Blastocyst Transfer?

A blastocyst is an embryo that has grown for 5 or 6 days after fertilization. A 3 day embryo is typically only about 6 to 8 cells in size. A blastocyst has divided into far more cells, and it is even possible to tell which are the baby and which will become the placenta.

3 day embryo 5 day embryo
3 Day Embryos (left) and 5 Day Blastocyst Embryo (right)

With blastocyst transfer the embryos are created in a laboratory and incubated until they grown to the blastocyst stage. They are then transferred to the mother’s womb as part of IVF treatment on day 5 or 6. Blastocyst transfer was first invented by fertility clinics in response to the rising number of women experiencing multiple births as a result of assisted reproductive technology (ART) treatments. Because fewer blastocyst embryos need to be transferred to secure a pregnancy, it was hoped that the incidence of twins, triplets and quadruplets could be reduced - multiple pregnancy carry risks, primarily miscarriage. As it turned out, the transfer of embryos on day 5 resulted in the same risk of twins in women under 35, than those transferred at day 3. However the number of triplets has been greatly reduced.

What Are The Benefits Of Blastocyst Transfer?

Only 30 to 50 percent of embryos created in a lab survive to blastocyst stage. Waiting to know which ones these are before transfer can improve the pregnancy success rate. Once transferred, a blastocyst, like any embryo, must successfully stick to the wall of the womb (implantation) for pregnancy to occur.

What Is The Procedure?

The procedure is similar to normal embryo transfer. But instead of being transferred after 2 to 3 days, they are transferred to the womb after 5 to 6 days.

What Are The Success Rates?

Initial studies revealed that embryos transferred at day 5 have a 50 percent implantation rate, compared to 30 percent in those transferred at day 3. These studies assume the patient has a good prognosis for IVF - that is, 10 or more follicles at least 12 mm large on the day of receiving hCG gonadotropin injection. However trials with mixed prognosis patients have yielded conflicting results. An analysis of 16 trials involving over a 1,000 2-3 day transfers and 1,000 5-7 transfers observed no difference in live birth rate. Nor, surprisingly, was the overall miscarriage or multiple pregnancy rates any different. It should be noted however, that women with a good prognosis for IVF still did better.

Who Is Most Likely To Benefit From It?

On average it takes 3 IVF cycles to bring about one live-birth (in other words, the first 2 attempts fail). Many fertility clinics now offer blastocyst transfer to improve the chance of a live-birth in the first cycle. This is particularly useful for younger women who have a good prognosis of IVF. See also: IVF success rates.

Your doctor may also recommend blastocyst transfer if you produced good quality embryos but they failed to implant in a previous IVF cycle. Alternatively he may recommend assisted hatching and 3 day transfer.

If you produce fewer healthy eggs than normal, it is not usually recommended.

What Problems Can It Cause?

Blastocyst transfer is more complicated than traditional 3 day embryo transfer. Older embryos require all sorts of things to keep up with their nutritional needs. For this reason, many clinics find it too difficult to grow enough blastocyst to transfer. The danger is, if you wait for your embryos to grow into blastocysts, you may end up with nothing to transfer. The embryologist advising your consultant may consider it safer to transfer a 2 or 3 day embryo than risk postponing transfer to day 5 or 6.

The second problem with blastocysts is that by the time of transfer they are already hatching out of their shell. This increases the risk of a blastocyst splitting in two, becoming identical twins. Identical twins are much more problematic than fraternal twins. Identical twins share the same placenta and sac and there is a risk that one twin will get more nutrients than the other (twin-twin transfusion syndrome, see pregnant with twins). The incidence of umbilical cord accidents is also higher. You are 4 to 5 times more likely to have identical twins undergoing blastocyst transfer. For this reason, some fertility centers only offer the procedure to women who have had several failed IVF cycles.

How Much Does It Cost?

Many clinics do not charge extra for a 5 day transfer compared to a 3 day transfer.

Personal Stories

On my first IVF I had a 5 day blastocyst with a fresh transfer. I tested positive for pregnancy but miscarried at week 5. On my second 5 day blastocyst (frozen), I was positive and am now 7 months pregnant. Fingers crossed!
Audrey, Cumberland, UK.

I think the 5 day transfer is best. I had 2 transferred on day 5 and got pregnant, but miscarried at week 6. Then I had another 2 transferred at day 5 and got pregnant with one. Had a beautiful baby girl last year.
Anne, Washington DC

I’ve had 4 fresh IVF cycles and 1 frozen IVF cycle. The only time I got pregnant was when I did a 5 day transfer. Unfortunately I lost the baby due to an immune issue. We’re waiting a while before trying again, but if I do it all again, I’ll definitely be doing a 5 day transfer.
Celine, Houston.

We were aiming for a 5 day transfer. When the doctor did egg retrieval surgery he retrieved 11 eggs but only 2 ended up being fertilised. We had to switch to a 3 day transfer then because the doctor was concerned we’d end up with nothing to transfer. It worked out great, our twins are 7 months old now.
Sally, London

  Related Articles on In Vitro Fertilization

For more information, see the following:

IVF protocols: Treatment plans explained.
Ovarian stimulation: Increasing your egg supply.

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