Embryo transfer: how does it work?

Considered the very last step of an IVF treatment, embryo transfer happens after the embryos are obtained in the laboratory. This procedure can be stressful for patients, but it can also be a relief because the embryo will finally be placed in the uterus awaiting implantation.

We explain everything you need to know about it below.

Embryo transfer: on what day of development?

During the IVF or IVF with egg donation treatment, the oocytes obtained are fertilized in the laboratory and kept under observation. Every day, the biologists’ job will be to check the progress of this fertilization and embryo development.

Nowadays, there are techniques in the laboratory that allow prolonged embryo culture: this means that the embryo does not run the risk of being damaged by the external environment and can develop in optimal conditions. At Vida Fertility, we make every effort to copy the natural environment of the uterus and allow embryos to better endure in the laboratory.

For this reason, we always recommend a transfer on D5 (day 5 of development), when the embryos have reached the blastocyst stage.

This prolonged culture has several advantages:

Embryo transfer on day 5 allows for a better embryo selection, since only the best quality embryos will be able to form a blastocyst.
Prolonged culture also allows the male factor to be tested too, since it is from D3 onwards that the quality of the spermatozoa comes into play in embryo development.
Blastocyst culture allows for the vitrification of the embryos without the risk of loss in devitrification, since 98% of embryos on D5 resume their development for a subsequent transfer.

However, transfer on D3 (day 3 of development) may sometimes be advisable if the patient has only one developing embryo.

What preparation is required for an embryo transfer?

Embryo transfer is a very simple procedure and does not require any special preparation.

Depending on whether the physician prefers a vaginal or abdominal ultrasound, the patient will be asked to come in with a full bladder.

It is also important to avoid taking anticoagulants (aspirin or heparin) that day and take them again the next day.

What are the steps or procedure of embryo transfer?

It is a very simple procedure: it does not require anesthesia, is painless and takes only 15 to 20 minutes.

This is what will happen during the transfer:

The physician will place a speculum and clean the cervix.
He/She will then slide a very fine catheter down to the fundus of the uterus.
The embryo will be prepared in the laboratory and then taken to the back of the uterus through this catheter. There are no obstacles for the embryo.
The biologist will then check to see if the embryo has stayed in the catheter.

What complications can arise during an embryo transfer?

Complications are very rare and may include:

Difficulty to reach the fundus of the uterus: this may occur if the cervix presents anomalies, or in case of previous cesarian sections, for example. In this case, the physician can use a softer catheter or a curved catheter to reach the cervix.
Pain in the patient: this may occur in cases of vaginismus or very inaccessible cervix. For these patients, we recommend the embryo transfer to be performed under anesthesia.
If the biologist finds the embryo in the catheter after the transfer, the operation has to be repeated.

Tips after an embryo transfer

How long should I rest after my embryo transfer?

Immediately after the embryo transfer, the patient will be placed in a resting room (30-40 minutes) and then she will be able to get up and resume her normal life.

What can’t be done after an embryo transfer?

Recommendations during the 10-day waiting period before the pregnancy test are as follows:

Avoid strenuous activities and stress.
Eat a healthy diet.
Drink plenty of water (at least 1L per day)
Avoid sexual intercourse.
Avoid baths and sudden temperature changes.

The medical staff will give you all the instructions for each case, as well as the treatment to be followed after your transfer.

At Vida Fertility we understand that embryo transfer is a very special moment for our patients: the end of a stage of treatment and the beginning of a new and hopeful one. Our staff will be there to give you all the necessary information and instructions for the day of your embryo transfer.

Request personalized information: contact us.

FAQs about embryo transfer

What day of the cycle does the embryo transfer take place?

Embryo transfer is typically performed between day 3 and day 5 after fertilisation. This depends on the development of the embryo and the specific treatment protocol.

For natural cycles, the transfer is synchronised with the woman’s ovulation, while in stimulated cycles, the endometrial receptivity is adjusted with hormone therapy to ensure the best implantation conditions.

In any case, it is advisable to consult a fertility specialist, as there are cases where the implantation window is displaced and the day of the transfer must be postponed or cancelled.

When is embryo transfer done at D3 or D5?

The decision on the day of embryo transfer is based on how the embryo development has progressed, the patient’s condition and the receptivity of the endometrium. The specialist will determine whether it is more beneficial to transfer on the third or fifth day of embryo development.

At Vida Fertility, we currently prefer to transfer a single embryo at the blastocyst stage to avoid multiple pregnancies. This transfer occurs on the fifth or sixth day of embryo development, as the probability of implantation is higher at this stage.

How long does it take for an embryo to implant after transfer?

Embryo implantation occurs between the seventh and tenth day after fertilisation. During this period, the embryo attaches to the endometrium, which is thickened and receptive to receive it.

This process may cause some of the blood vessels in the endometrium to rupture, known as the adhesion phase, marking the beginning of pregnancy. Approximately 30% of women experience light bleeding, called implantation bleeding. Thanks to this adhesion, the embryo begins to receive nutrients from the endometrium, which are essential for its initial development before the full formation of the placenta.

What is the best day to perform the embryo transfer?

How long does it take for an embryo to implant after transfer?
Embryo implantation occurs between the seventh and tenth day after fertilization. During this period, the embryo attaches to the endometrium, which is thickened and receptive to receive it.

This process can cause some blood vessels in the endometrium to rupture, known as the adhesion phase, marking the beginning of pregnancy. Approximately 30% of women experience slight bleeding, called implantation bleeding. Thanks to this adhesion, the embryo begins to receive nutrients from the endometrium, which are essential for its initial development before the placenta is fully formed.

What are the chances of getting pregnant in the first IVF?

At Vida Fertility, first-time IVF-ICSI treatment success rates vary according to the age of the patient:

For women over 35, the success rate is 62.3%.
For women between 35 and 39, the success rate decreases to 51.1%.
For women over 40, the rate is 42.8%.

In addition, 53.5% of the embryos reach the blastocyst stage and in 60% of the cycles embryos are successfully frozen. These data reflect the efficiency and experience of Vida Fertility in the management of assisted fertility.

How many embryos should be transferred?

Currently, the medical consensus is to transfer a single embryo, regardless of whether the treatment is a fresh cycle, with frozen embryos, or through egg donation.

Advances in assisted reproduction techniques now allow for much more accurate embryo evaluation in the laboratory, making it advisable to prioritize the transfer of a single high-quality embryo.

Furthermore, in some medical cases (for example, in women with immune disorders), it is not advisable to transfer more than one embryo.

Can you cancel my embryo transfer?

It is important to note that sometimes it is necessary to cancel embryo transfer due to lack of embryo development or inadequate endometrial preparation.

The main reasons for the absence of embryos in an IVF cycle include fertilisation failure and arrests in embryo development, often due to genetic alterations.

In addition, in case the endometrium is not ready, the embryos obtained are frozen and transferred in a later cycle, known as a delayed transfer.

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