If there is yolk sac without fetal heart and buds after successful IVF transfer, it is considered that the pregnancy period is too short, the ultrasound observation angle is not ideal, and the embryo stops, etc. The details are as follows. 1. The pregnancy is too short: usually the fetal buds will appear in 40-50 days of pregnancy, and the fetal heart will appear in 50-60 days. It is possible that the pregnancy is still relatively short, so there is no development of fetal buds and fetal heart, you can delay 1-2 weeks before going back to the hospital for review. 2. Unsatisfactory ultrasound angle: It may be due to the accumulation of gas in the intestinal cavity of the examinee, bladder holding, too thick abdominal fat, or unsatisfactory observation angle due to the position of the uterus. 3. Embryonic arrest: If the yolk sac is an empty sac without real fetal buds and fetal heart, it may be embryonic arrest, and most of the embryos are eliminated naturally due to poor quality. It may be due to abnormal fetal development leading to embryonic arrest, or it may be due to viral infection caused by high fever or flu in the mother, leading to miscarriage or embryonic arrest. Therefore, if any of these abnormalities occur during the ultrasound examination, you should seek medical advice. Doctors usually review the ultrasound and check HCG (human chorionic gonadotropin) and progesterone based on the patient’s medical history and symptoms to help clarify the cause.