The yolk sac can be seen by ultrasound on day 40 of early pregnancy, and the fetal bud and heartbeat can be seen on day 45. 30 days of transfer without yolk sac is not enough for pregnancy. Under normal circumstances in IVF, embryos need to be transferred to the uterine cavity for implantation, growth and development, and most of them will have their chorionic gonadotropin levels increased in blood tests around 7-8 days after the transfer, and gynecological ultrasound will be done around 20 days after the IVF transfer, and there will be the growth of a gestational sac in the uterine cavity, and the chorionic gonadotropin levels in blood tests are doubled every other day, and the progesterone levels are also increased The diagnosis of a normal intrauterine pregnancy can be made. The absence of yolk sac development 30 days after in vitro transfer is mostly due to poor quality of embryo or endometrial environment not suitable for egg growth and development, resulting in embryonic abortion and spontaneous miscarriage, which should be treated symptomatically in time.