The following morning, the egg is checked for evidence of fertilisation. Assuming this has taken place, the newly formed embryo needs to be cultured to check it is likely to continue to develop. The ability of the embryoscope to show embryologists how the embryo advanced overnight is instrumental in determining whether these cells have divided normally, and check for any abnormal development.
The cells will keep splitting into two in a healthy embryo, gradually increasing the cell number. At this point, it may be decided to transfer the embryo back into the uterus. This is because despite huge developments in science and the ability to sustain embryos in the lab, the uterus is still superior and naturally gives them the best environment to grow in.
However, if there are several embryos from the same couple, many of them may look similar at this stage, making the clinical decision as to which should be transferred quite difficult.
In order to see which of several are the healthiest, they can remain in the incubator a further two days. Those which survive this have proven themselves to be extremely good candidates for transfer and a successful pregnancy.
The embryo is not graded by embryologists on this day, as all compacting embryos look fairly similar and will not give much indication of their quality. A healthy embryo will form a blastocyst by now, dividing its cells into sections that will form the foetal matter and placenta. It is placed in a catheter which is then inserted into the cervix, and a clinician will position it in an optimal location in the uterus.
The morphology or the grading of the embryo can help inform your physician of the chances that the embryo will result in a successful transfer. After your egg retrieval, an embryologist will assess each egg checking for maturity.
The embryologist will remove the cumulus cells, the cells surrounding the egg that provides nourishment as it grew. Each mature egg will be fertilized. There are two different fertilization methods used today, though ICSI is used more frequently. After fertilization, the embryologist will place your eggs into the incubator; this process takes around 15 to 18 hour..
Typically, the day after fertilization day 1 an embryologist will check to see if fertilization was successful. However, fertilization rates can vary. You may wish to ask your doctor how many eggs they anticipate to fertilize. On the second day after egg retrieval, a developing embryo should consist of cells. Most clinics do not grade the day 2 embryo as they are still just beginning to grow. Depending on your treatment plan, embryos may be transferred back to the uterus at day 3 or at the blastocyst stage typically day 5 or 6.
On day 3, a well-developing embryos should have cells. Embryo quality as we see it under the microscope in the IVF lab gives us some reasonable ability to predict the chances for pregnancy after the embryo transfer procedure. The true genetic potential of the embryo to continue normal development is very difficult to measure accurately unless we utilize preimplantation genetic screening PGS to select chromosomally normal embryos for transfer.
Chromosomal testing with PGS is done on several cells that are removed from expanded blastocyst stage embryos via trophectoderm biopsy. When PGS is done, the embryos are frozen after they are biopsied because the genetic testing results do not come back soon enough to do a fresh embryo transfer. In these cases we do a frozen embryo transfer about 4 weeks later.
An important variable that is often overlooked is the embryo transfer technique. A smooth transfer with no trauma to the endometrial lining is essential to give the embryos the best chance for implantation and continuation of normal development.
Ultimately, the true test of embryo quality is whether it implants and develops normally and eventually goes home from the hospital with mom and dad. Unfortunately, there is no agreement at all as to which system to use. We all think we have the best one — and that the rest of the world should use our system — there are lots of big egos in the IVF world. As far as we know, the children born from low grade embryos are just as cute, intelligent, strong, etc.
The only difference seems to be with the chance for the embryo s to result in a pregnancy. Embryo quality, to a great extent, is determined by the quality of the egg from which it started. Tests of ovarian reserve, such as the day 3 FSH hormone assessment , and antral follicle counts can give us useful information about egg quantity, but are not useful in predicting egg quality. If we could improve the quality of the eggs that we start with in IVF, we would have a better chance of having a successful outcome.
Egg quality is mostly determined by the chromosomal and genetic competence of the individual egg. There is no treatment to fix chromosomal or genetic defects. Therefore, we do our best with the eggs that we retrieve, or we screen blastocyst stage embryos for chromosomal status before transferring.
Learn how the number of eggs retrieved with IVF affects the chance for succes s. The quality of the ovarian stimulation process and the quality of the IVF laboratory itself are also very significant variables that impact the quality of the resulting embryos. Patient Resource Center.
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