What is a Blastocyst Transfer?

What is a Blastocyst Transfer?

What is a Blastocyst Transfer?

Assisted reproduction techniques have suffered a lot of changes and improvements in the last decades. The specialists have determined that some changes in different steps of the traditional procedures can mean a significant increase in pregnancy rates.

One of the most innovative changes is the transfer of Blastocyst instead of embryos in the final stage of an In Vitro Fertilization (IVF) procedure. A blastocyst is an embryo with approximately 5 to 7 days of development after fecundation. It has 2 different types of cells, some of them are in the surface and will allow the formation of the placenta, while the others are in the center of the blastocyst and will allow the fetus development.


As it was said before, a blastocyst transfer refers to the use of blastocysts (and no embryos) during the transfer process in the In Vitro Fertilization assisted reproduction technique.

During the last stage of the IVF, the blastocyst must be carefully placed in the middle of the endometrial layer of the uterus, so they can continue the natural pregnancy process and get implanted in the uterus to continue its development.


In most cases, it is an outpatient procedure. The best method to perform this stage of the IVF is the ultrasound guided blastocyst transfer.

In this procedure, the woman receives injections to produce hormonal stimulation and prepare the endometrium to receive and implant the blastocysts. According to the experts’ recommendations, more than one blastocyst is transferred and the doctor uses ultrasound to determine the exact place where he/she will place them.


Nowadays, experts of the Advanced Fertility Center of Chicago say that it is better to use the blastocyst transfer and not the embryo transfer, and this can be explained by the natural pregnancy progress.

In a natural pregnancy, embryos of 2-3 days after fecundation are usually in the Fallopian tubes and only arrive to the uterus 3 or 4 days after that (between 7 and 8 days after fecundation), when the blastocyst formation has started.

In the past years, embryos were usually transferred 2 or 3 days after the fecundation and many of them subsequently died in the womb. Experts say that if the embryos are maintained in proper culture conditions, they can develop themselves until the stage of blastocyst and they can be artificially transferred to the uterus, which is more similar to the natural process of pregnancy.

Likewise, when embryos are maintained under standard IVF culture conditions, just 25 to 60% of the obtained embryos can continue a proper development after 5 days of fertilization. So, by transferring blastocysts, there are more probabilities of transferring high-quality embryos able to continue their development in the uterus.

The last stage of an IVF technique is very important to achieve high rates of pregnancy success with this method. It doesn't matter how precise and careful the entire process was, if the embryo or blastocyst transfer has a problem, the result of the entire process can be altered.


According to recent studies, the best day for blastocyst transfer is the day 5-6 because after performing the artificial fecundation, on this day, most embryos have developed into blastocysts but have not grown further than that.

However, many studies have shown that when the fecundated ova are transferred during the blastocyst period (which can be detected by a qualified specialist), the probability of achieving a successful pregnancy is higher.


Many experts of the Advanced Fertility Center of Chicago recommend their patients to have a normal life after a blastocyst transfer. However, some situations like lifting heavy things, experiencing stressful situations, performing intense exercises, among others must be avoided.

It is important to know that, in some particular situations, experts may recommend taking a break from work for a few days. However, this will strongly depend on the type of work of the patient or other patient’s particular conditions, like being older than 40 years or diseases that may alter the development of a pregnancy.

Likewise, after a blastocyst transfer the couple/woman must wait between 1 and 2 weeks to undergo a pregnancy test that can be trustworthy. This time seems to be short, but for people who really desire pregnancy, it can be the longest days of their lives.

Last update 5th of September 2019

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