When there are only two good quality embryos, it is more suitable for sac transfer, which has better pregnancy rate and live birth rate compared to fresh embryo transfer.
In the initial stage of IVF assisted conception, doctors mostly adopt fresh embryo transfer, that is, 3 days after egg retrieval, when eggs and sperms are fertilized in vitro to form early embryos for transfer.
Later, it was found that the success rate of IVF would be higher if the embryos were cultured in vitro for the fifth day to form blastocysts, i.e., blastocyst-raising transfer. Therefore, when there are only two good quality embryos, it is recommended that blastocyst-raising transfer is preferred.
In addition, compared with blastocyst transfer, fresh embryo transfer is more demanding for women’s uterine conditions and hormone levels in the body, the uterine lining must reach a certain thickness and the ovarian secretion function is good. If the uterine environment is not up to standard or the hormone level is too low, it is not easy to survive after the transfer.
At present, in vitro fertilization process, selecting high-quality adoptive sacs to be transferred to the uterine cavity for implantation, growth and development is a commonly used method, which greatly improves the probability of embryo survival.
The exact choice of transfer method is also related to the hospital laboratory equipment, experience of the culturing doctor, etc. It is recommended to follow the advice of the interviewing doctor.