Which is Better for IVF Treatment: Fresh Embryos, Frozen Embryos, or Blastocysts?

2024-08-15 21:30:58，visits： 159

In IVF technology, fresh embryos, frozen embryos, and blastocysts are common terms. Understanding their differences is crucial for choosing the most suitable treatment plan. The IVF process starts with egg retrieval, which we define as day D0. On this day, sperm is combined with eggs in a culture dish to form fertilized eggs. This fertilized egg then gradually develops into an embryo. Typically, on day 3 after egg retrieval, the embryo reaches the embryonic stage, known as a D3 embryo. If the embryo continues to culture for 2 to 3 more days, it typically forms a blastocyst, which is known as a D5 blastocyst.

Whether it is a D3 embryo or a D5 blastocyst, if they have not undergone freezing, they are considered fresh embryos. If the embryo or blastocyst has been frozen before transfer, it is referred to as a frozen embryo.

Comparing D3 embryos and D5 blastocysts, D5 blastocysts are generally more advantageous. Blastocysts have developed for a longer time in vitro, and they have a higher affinity for the uterine lining compared to embryos. Dr. Nathan Zhang points out that in the U.S., embryos are usually developed to day 5, forming blastocysts before being transferred. This approach increases the likelihood of conception and reduces the risk of miscarriage and fetal loss. In contrast, most domestic hospitals transfer embryos on day 3, which is considered outdated in the U.S. due to its lower success rates.

Both fresh and frozen embryos have their pros and cons. The main advantage of fresh embryos is that they shorten the overall IVF treatment time, as fresh embryo transfer occurs soon after egg retrieval. However, due to the impact of ovarian stimulation medications or endocrine regulation drugs during the fresh cycle, the uterine lining's functionality may be impaired, which is not ideal for embryo implantation. In contrast, frozen embryo transfer allows the woman's uterus to be better rested and restored before embryo transfer, which helps increase the uterus's acceptance rate of frozen embryos. Although the freezing and thawing process may reduce some embryos' viability and frozen embryo transfer requires a longer wait time, its success rate is often slightly higher than that of fresh embryo transfer.

Recent studies indicate that frozen embryo transfer has a higher live birth rate in patients with polycystic ovary syndrome (PCOS) compared to fresh embryo transfer, and it also has a lower risk of ovarian hyperstimulation syndrome. For patients with normal ovulation and without PCOS, the live birth rate for frozen embryos and fresh embryos does not differ significantly, but frozen embryo transfer significantly reduces the risk of ovarian hyperstimulation syndrome.

Advancements in freezing technology have led to higher success rates for frozen embryo transfers today. Frozen embryos provide IVF mothers with more time to condition their uterine lining, ensuring a better state for embryo transfer. Additionally, frozen embryos allow for more complex genetic screening, further improving embryo quality. Frozen embryos offer IVF mothers more options, as embryos can be thawed and used if a fresh embryo transfer fails, avoiding the need for additional ovarian stimulation and egg retrieval.

Choosing the right doctor and laboratory is crucial for increasing success rates, especially for women over 40. Currently, IVF USA provides services including egg freezing and IVF in the U.S., as well as expanding its services to Japan, Thailand, Mexico, Taiwan, Hong Kong, and other regions, working closely with IVF doctors worldwide. If you have further questions or need personalized advice, please contact IVF USA. Dr. Nathan Zhang and his team will offer you professional guidance and assistance.