Causes & Treatment

The Importance of the IVF Embryo Transfer, the Process and Variables

Eloise Edington | 31 Mar 2021

Today on Fertility Help Hub’s blog, we hear from the fertility specialists at Ure Centro Gutenberg (in beautiful, sunny Malaga, Spain), about the process, variables and importance of the embryo transfer – a critical stage within an IVF cycle. Our partner fertility specialists also discuss what needs to be taken into account and why sometimes it can’t happen in the same IVF cycle.

Words by URE Centro Gutenberg

www.fertilityclinicspain.com | @urecentrogutenberg

An In Vitro Fertilization (IVF) treatment involves several very important moments. It all starts with a first visit to your fertility clinic to carry out a complete study of the woman and/or couple. After the fertility diagnosis, your IVF treatment will begin with the controlled ovarian stimulation phase (ultrasound and fertility blood tests). Then it will be time to perform the follicular puncture, the insemination of the oocytes (eggs), usually by ICSI, the embryo culture and, finally, the intrauterine transfer of embryos.

This last step consists of depositing in the uterine (endometrial) cavity up to a maximum of two selected embryos. If possible, we will freeze the remaining viable embryos. It is at this moment when we can affirm that we have finished the IVF treatment.

After a period of embryo culture, which keeps the embryos between 3 and 5 days in conventional incubators, or in Embryoscope, the fertility specialist or embryologist will indicate the day to come in for the embryo transfer. The embryo transfer is a very important moment, and as such, for IVF success, it’s useful to understand a series of variables that we will explain to you below.

What should you take into account on the day of the embryo transfer?

First of all, and although it may seem obvious, it is an essential requirement that this procedure is performed by a trained and experienced fertility specialist. At URE Centro Gutenberg, the embryo transfer is performed in the operating room, under abdominal ultrasound vision. But, unlike ovarian puncture (egg retrieval), it does not require anaesthesia. You will be accompanied by a fertility specialist, the embryologist and a DUE.

To carry out the embryo transfer, it is important that you enter the operating room with a full bladder. This measure has two objectives: with a full bladder, the position of the uterus (womb) is improved, which facilitates the embryo transfer. The visualization of the uterus on the abdominal ultrasound is also improved. In addition, you must bear in mind that on the day of the embryo transfer you should not use perfumes or makeup, since embryos are very sensitive to any environmental change in temperature, aromas, light, etc.

What is the process of an embryo transfer?

Once in the operating room, the woman will adjust as she would for a vaginal ultrasound. The doctor will insert a vaginal speculum to visualise the cervix, and will proceed, very carefully, to clean (with sterile gauze and embryo culture medium) the remains of medication, aspiration of cervical mucus etc. Once the cervix is cleaned, the cervical canal will be cannulated. For this part of the process, a catheter is used which (based on our experience at the Gutenberg Centre URE) must be the softest possible, to avoid discomfort to the patient.

The embryologist will load the selected embryo(s) into a much softer internal catheter, which the fertility specialist will insert through the cannula, with which the cervical canal was cannulated. The tip of the internal catheter will be housed 10-15 mm from the uterine fundus, where the selected embryo(s) will be deposited. Although it is a delicate procedure, an IVF frozen embryo transfer usually does not take more than ten minutes. After this, the patient remains in the operating room for a further ten minutes, after which she can return home.

When can an embryo transfer not be performed?

Unfortunately, we come across situations where an embryo transfer is not possible, for various reasons. These are the main causes:

Poor embryo quality
Poor preparation of the cavity (endometrium)
Risk of ovarian hyperstimulation syndrome (OHSS)

Except in the case of poor embryo quality (in which it would be necessary to repeat the IVF cycle), in the rest of the cases, what happens is that the embryo transfer will take place after a few weeks – in a subsequent cycle. To do this, we freeze the embryos and prepare the woman’s endometrium (womb lining) to receive them once they are thawed. Obviously, this situation leads to the prolongation of the fertility treatment, but it improves the results in terms of the probability of pregnancy and IVF success, rather than if the embryos had been transferred in the same cycle.

Why transfer one embryo in IVF versus two?

Assisted reproduction techniques (ART) have been found responsible for the increase in multiples (the likelihood of conceiving twins naturally is around 1.4%) which pose risks to the mother during pregnancy, as well as to the newborns. That is why one of the main goals of assisted reproduction specialists is to achieve an incidence of multiples (using ART) that resembles the incidence observed in natural pregnancies as closely as possible, without decreasing pregnancy IVF success rates.

We still have a long way to go, but the way forward is increasingly clear. With improvements in systems for embryo assessment (which make it possible to transfer a single embryo in IVF), excellent embryo cryopreservation results and, little by little, increased public awareness about the risks associated with multiple pregnancies, we are on our way to making more single embryo transfers a reality.

What Happens after an Embryo Transfer?

Once the IVF frozen embryo transfer has been carried out, it is generally recommended that the patient keeps relatively rested and avoids sexual intercourse – although this has not been shown to improve the chances of IVF success / pregnancy. And what next? Now you have the 2WW (two week wait) for the result of the pregnancy test. Try and keep positive – easier said than done, we know.

If you have any doubts about this or any other assisted reproduction procedure, then remember that in our frequently asked questions and answers section you will find a lot of information. If that is not enough, do not hesitate to contact us. Our fertility specialists are always happy to assist you!

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