Many sisters have a question in the IVF cycle: why is the number of basal follicles examined before the week not equal to the number of eggs retrieved at the end, and the number of final embryos available is discounted on this basis? Today we come together to unravel the mystery!
The number of follicles based ≠ the number of follicles retrieved
In its natural state, a woman of normal reproductive age will have 10-20 follicles developing every month, but eventually only one mature egg will be released, and the rest will be locked and apoptosis.
Ovulation induction is the promotion of these eggs that should be eliminated, giving them nutrients to allow them to mature.
However, each follicle responds to the drug to a different degree, so there will be cases of different sizes, over-mature and underdeveloped situations, usually the number of eggs obtained is generally estimated by HCG day (the day of night injection), the number of follicles with a diameter of ≥ 14 mm is estimated, so the number of follicles ≠ the number of eggs obtained.
The number of eggs obtained ≠ the number of embryos
Many friends are wondering, my report shows that the follicles are well developed, and the number of final eggs retrieved is not low, but the formation of embryos is very small.
This is because: First of all, not all the eggs retrieved by IVF are mature and available, and the general egg maturation rate is about 80%. Secondly, only mature eggs can be fertilized, and the fertilization rate of IVF is generally around 70%.
Even if the final fertilization is successful, there is no guarantee that the fracture will be completed and the embryo will be developed. The normal rate of embryo division is that 8 cleft balls can be observed on the third day after fertilization.
Therefore, there will be a certain gap between the number of eggs retrieved and the number of embryos that will eventually be formed.
Number of embryos≠ number of PGT embryos
The third generation of IVF with PGT screening diagnostic technology to detect all the chromosomes of blastocysts and eliminate hundreds of genetic diseases to ensure the high quality and health of blastocysts will be transplanted into the mother, in this process, will gradually eliminate uninspired, abnormal insemination or unqualified embryonic development, which is a process of selecting elite soldiers.
Therefore, there will be a certain gap between the number of embryos formed and the number of blastocysts that can eventually be transferred, and sometimes there will be no healthy and high-quality embryos available for transfer.
For friends who are preparing for IVF, what we can do is to improve the quality of our sperm and eggs. Then, with the help of professional doctors and drugs to get more healthy embryos, we can improve our good pregnancy rate.