In the Russian IVF process, fresh embryo transfer and frozen embryo transfer is the most common two ways, the two suitable for the population is not the same, each has its own advantages, we generally have a cycle of egg retrieval called fresh cycle, if there is a suitable embryo, 3-5 days after egg retrieval, assess the endometrium and pelvic situation, if there is no factor that is not conducive to embryo implantation, you can choose fresh embryo transfer. After there are frozen embryos, the cycle of only transferred embryos is called the freezing cycle or frozen embryo recovery cycle and freeze-thaw cycle. So in which cases must I choose frozen embryo transfer?
1. Those who are at high risk of ovarian hyperstimulation
Women who are young, well-functioning, thin, or have POLYCYS are more likely to develop too many follicles in fresh cycles of ovulation induction, which leads to ovarian hyperstimulation syndrome (OHSS), which usually manifests as bloating, abdominal pain, chest tightness, nausea, less urine, and symptoms related to ascites, pleural fluid, and thromboembolism. The most effective measure to prevent the occurrence of OHSS is whole embryo freezing, because HCG produced after pregnancy can further aggravate the progression of ovarian hyperstimulation. If the number of eggs obtained in a fresh cycle is ≥ 15, the estrogen level > 15000 pmol/ml, which has a higher risk of OHSS, and it is usually recommended to freeze whole embryos.
2. Those who raise progesterone in advance during ovulation monitoring
During the ovulation induction process, the doctor will adjust the dose and determine the night needle (trigger) time according to the patient's ultrasound monitoring results and the estradiol, luteinizing hormone, and progesterone values of the blood test. Some patients have an early increase in progesterone levels during follicle development, and this early exposure of the endometrium to high progesterone can lead to the development of the embryo and the endometrium out of sync, resulting in a decline in embryo implantation rates and clinical pregnancy rates. Therefore, the progesterone is raised in advance, and the fresh embryo transplant needs to be cancelled and the whole embryo is frozen.
3. Sufficient embryo reserves:
If the patient obtains more embryos of relatively high quality, embryo freezing can be selected after fresh embryo transfer or directly. The advantage of this is that once the pregnancy fails, there can be spare embryos for direct transfer, avoiding the need to promote ovulation and egg retrieval again, saving time and treatment costs. In addition to this, if the pregnancy is successful, it is possible to prepare for reproduction.
4. The patient's uterine environment is not good:
During IVF treatment, while inducing ovulation, the uterine environment will also be affected. If the development of the egg and the endometrium are not synchronized, it will affect the tolerance of the endometrium to the embryo, resulting in pregnancy failure or miscarriage. Therefore, the doctor will recommend embryo freezing first, and then perform the resuscitation transfer when the time is right.
5. Pelvic abnormalities
When there is significant hydrosalpinx, the regurgitation of hydrosalpinx in the uterine cavity or the action of inflammatory factors affects the implantation of the embryo. You can choose to freeze the whole embryo and process the appeal before performing the embryo transfer.
Embryo transfer is very helpful for people who are temporarily unsuitable for transplantation after egg retrieval, it can give the uterine ovaries and body enough repair time, so it can improve the success rate of pregnancy in time, but everyone's physical condition is different, suitable for the transfer of that kind of embryo, should be developed by Russian experts according to the actual situation.