For many of those undergoing in vitro fertilization (IVF) treatment at Fertility Specialists of Texas, blastocyst embryo transfer capabilities have led to safer, more effective treatment. The human embryo enters the blastocyst stage 5-6 days after fertilization, at which time it is composed of 70 to 100 cells. During IVF treatment, transfer of the embryo at the blastocyst stage offers a number of distinct advantages that can increase pregnancy rates and virtually eliminate the likelihood of dangerous multiple births (triplets and quadruplets, for instance).
How it Works
During IVF treatment with blastocyst transfer, unfertilized eggs (oocytes) are retrieved from the ovary. They are then fertilized in our state-of-the-art IVF lab, creating an embryo. Instead of being transferred to the uterus after 3 days, which is the case during traditional IVF treatment, the embryos are allowed to progress to the blastocyst stage over a period of 5-6 days. During unassisted fertilization, the embryo must reach the blastocyst stage in order to attach to the uterine wall. During blastocyst transfer IVF, the embryos are implanted in the uterus during this same stage of development, some consider this to be a more natural implantation method.
Because the embryos are allowed to progress to the blastocyst stage prior to implantation, our embryologists are able to select, with greater certainty, those embryos most likely to result in pregnancy. Prior to blastocyst embryo transfer, it is normal for a number of embryos to stop growing. Certain embryos have greater development potential than others. While not every embryo that reaches the blastocyst stage continues to grow in further stages, the likelihood it will do so is greatly increased. By waiting to see which embryos have the ability to reach the blastocyst stage, and applying other criteria during the embryo selection process, there is a greater chance of success associated with blastocyst embryo transfer than with other methods.
Reducing the Likelihood of Multiple Births
During standard IVF treatment, multiple embryos are typically implanted in the uterus. This is done to overcome the challenges posed by embryos that stop growing during the blastocyst or subsequent stages. Because not all embryos will grow to maturity, transferring multiple embryos helps increase the pregnancy rate for IVF procedures. If, however, despite the statistical likelihood of them not doing so, multiple embryos continue to grow, potentially dangerous multiple births can be the result. During IVF treatment with blastocyst embryo transfer, we are able to see which embryos grow past the blastocyst stage before they are transferred to the uterus. This means, for instance, only 1 or 2 embryos can be transferred, each of which has a greater likelihood of success.