The fetal bud refers to the embryo before 56 days of pregnancy, and the fetal heart refers to the beating of the primitive fetal heart tube, both of which can be detected by ultrasound examination to determine the fetal growth and development, and can usually be detected at 42-49 days of pregnancy. The fetal heartbeat and fetal bud can be detected on day 47 of pregnancy, but it is normal for some pregnant women not to be detected. If the fetal heartbeat and fetal bud are not detected on the 47th day of pregnancy, it is mostly considered that the pregnant women have irregular periods, the pregnancy period is calculated from the first day of the last menstruation, some pregnant women have irregular periods, mainly the delayed population, the ovulation time is delayed, so the actual time of sperm implantation will be later, and the fetal bud will naturally appear later. Other conditions are low progesterone, late development of the gestational sac, etc. If there is no other discomfort, pregnant women can wait patiently. It is recommended to check again after 1-2 weeks, paying attention to the test data of blood sugar, estradiol, HCG and progesterone to check for abnormalities. If fetal heart and fetal bud are still not seen after 60 days, then promptly recheck. Currently, it is clinically believed that the absence of fetal bud and fetal heart after 11 days for a pregnant sac with yolk sac or 14 days for a pregnant sac without yolk sac can be initially judged as embryonic abortion. If there is a fetal bud and fetal heart in the uterus detected on day 47 of pregnancy, it is clearly an intrauterine pregnancy, and further physical examination can be followed to observe the fetal development.