Is frozen embryo better than blastocyst?

Before doing IVF transplantation, most pregnant mothers who are doing IVF are worried. If they want to do IVF transplantation immediately, is it better to use frozen embryos or embryos? First of all, pregnant mothers should understand that frozen embryos for IVF are generally transplanted 3 days after shaping, while IVF embryos are transplanted 5 days after shaping. Why is it better to use IVF embryos? Let me summarize the three levels.

1. Why do we need to carry out embryo transfer?

1. The number of cells in the cleavage-stage embryo on the 3rd day is relatively small, generally around 8. By increasing the external shaping time of the test tube embryo to the 5th to 6th day, the test tube embryo will continue to grow and develop into embryos. At this time, the number of cells reaches dozens to more than a hundred, and has divided to produce trophoblast cells and inner cell mass cells. The embryo shaping process is a further selection of test tube embryos. The proportion of aneuploid and chromosomally abnormal test tube embryos will be reduced to a certain extent, and test tube embryos of poor quality will be eliminated during the further shaping process.

2. Embryo transfer is more in line with the physiological implantation time, because in the process of natural pregnancy, the test tube embryo after fertilization is already a morula to embryo when it arrives in the uterine cavity; embryo transfer shortens the time for the test tube embryo to be implanted in the uterine wall, reduces the adverse conditions that the test tube embryo may experience before implantation, and the implantation rate and pregnancy rate will gradually increase.

3. Single embryo transplantation for high-quality embryos can also reduce the occurrence of multiple pregnancies and the risks to maternal and child health that may be caused by multiple pregnancies. It is particularly suitable for patients with a history of uterine scars, uterine malformations, or hypertension during pregnancy.

2. What are the risks of embryo shaping?

1. The shape of the test tube embryo in the cleavage stage cannot accurately predict the production of the embryo. Generally, about 60% of high-quality test tube embryos on the 3rd day can produce embryos. The embryo production rate of non-high-quality test tube embryos will be lower. Therefore, for all patients, especially older patients with a small number of eggs, there is a risk of not being able to transplant test tube embryos due to no embryo production.

2. There are reports that embryo shaping will increase the probability of monozygotic twins, which are prone to miscarriage, developmental malformations, twin-infant syndrome, etc., and will also increase the incidence of premature birth and pregnancy-related perinatal diseases.

3. Whether increasing the time spent on physical shaping will cause abnormalities in genetic imprinting has always been a concern, and the long-term impact on offspring also needs to be observed.

3. Does successful cyst culture mean pregnancy is certain?

Embryo shaping can replace some test tube embryos with poor development potential, but it cannot replace all aneuploid test tube embryos. Whether embryo transplantation can be successfully implanted is affected by many factors, such as the receptivity of the uterine wall, genetic abnormalities of the embedded test tube embryos, and the difficulty level of transplantation.