How Does Embryonic Development Occur in IVF (In Vitro Fertilization)?

The embryonic development process of in vitro fertilization is generally divided into several steps: physical examination, egg retrieval, in vitro fertilization, and embryo transfer to the uterus.

1. Physical Examination and Ovarian Stimulation: Women normally ovulate naturally once a month, but in vitro fertilization requires more than one egg. Therefore, medical methods are used to stimulate ovulation to increase the number of eggs released. Women undergo a process of taking ovulation-inducing drugs and receiving ovulation-stimulating injections, which may produce some side effects on their bodies. These side effects may include abdominal pain, weight gain, nausea, vomiting, and irritation to the ovaries.

2. Egg Retrieval: After a certain period of time following the first step, the ovarian follicles gradually mature, and it is time to proceed to the next step of egg retrieval. The process of egg retrieval is relatively complex, involving the insertion of an egg retrieval needle into the ovary through the vagina to puncture the ovarian follicles and extract the follicular fluid, which is then aspirated into a test tube along with the egg retrieval needle. Simultaneously, sperm retrieval is also performed. The entire process is usually performed under anesthesia, so the pain is not significant.

3. In Vitro Fertilization: After both sperm and eggs are retrieved, they are placed together in a container for cultivation. Artificial insemination can be performed by injecting sperm into the egg, or natural fertilization can be allowed to occur. If no suitable eggs or sperm are found during this process, or if fertilization fails, the steps 1, 2, and 3 may need to be repeated.

4. Embryo Transfer to the Uterus: After successful in vitro fertilization in step 3, the doctor selects high-quality embryos for transfer to the uterus. This step is also crucial, and failure at this stage can be particularly discouraging for both the doctor and the recipient, as it means the entire process needs to be restarted. Typically, 2-3 embryos are transferred at a time, as too few may result in a low success rate, while too many may increase the risk of pregnancy complications. Successful embryo transfer does not guarantee the final victory, as the recipient needs to rest sufficiently and avoid stimulating foods. Pregnancy confirmation is determined after 14 days, and embryonic development is observed after 21 days. A month later, a check is made to confirm intrauterine pregnancy and the number of fetuses, and pregnancy can be considered safe only after the fetal heartbeat is detected.