Usually on the 3rd day after egg retrieval, many of you will get one or several good quality embryos, at this time some of you can have embryo transfer on the same day, and most of you need to freeze the embryos for subsequent transfer. So what are the situations where we would forgo a fresh cycle transfer? Endometrial condition Good endometrium is the primary condition for embryo growth. Having thin endometrium, poor morphology, poor endometrial blood flow condition, endometrial hyperplasia or endometrial polyp, and endometrium out of sync with embryo development are not conducive to embryo implantation and development. Status of uterus and both adnexa If there are uterine fibroids and adenomyosis, it is like having stones and hollows in the soil, the embryo is not easy to implant in the normal site and there is a risk of miscarriage at the later stage. Patients with fluid in the fallopian tubes and pelvic inflammatory disease are also not suitable for embryo transfer. Maternal health condition I believe it is not difficult to understand that good health condition of the mother is the guarantee of healthy development of the fetus. Except for some serious medical and surgical diseases, fever and diarrhea are not suitable for embryo transfer. This is because in these cases, the homeostasis of the body’s internal environment is disrupted and water and electrolyte regulation is imbalanced, which may cause adverse reactions such as contractions. Prevention of ovarian hyperstimulation Fresh cycle transfer is usually cancelled when E2 (estradiol) levels are too high during cycle testing and there is a risk of hyperstimulation. If the pregnancy continues at this point, E2 levels will continue to rise, leading to massive ascites/thoracic fluid production, thrombosis, liver and kidney damage, and ultimately endangering the life of the mother and child. This is the reason why fresh cycle transfer is cancelled. If you need to freeze embryos, there is no need to be too anxious, as there is no big difference between fresh cycle transfer and frozen and thawed transfer in terms of outcome.