The fetal heart can usually be seen by ultrasound around 6-7 weeks of pregnancy, but sometimes there are variations in embryonic development and it may be prolonged for 1-2 weeks before it is seen. The first thing seen through ultrasound in early pregnancy is the gestational sac. Around 6-7 weeks of pregnancy, the embryo buds and primitive heart tube pulsations can be seen. If a woman has regular menstrual periods of around 28 days, counting from the first day of her last menstrual period, the fetal heart may usually be seen 6-7 weeks after menopause. If a woman has a long or irregular menstrual cycle, it may take 1-2 weeks longer to be seen. If the ultrasound is performed at 7-8 weeks of menopause and the fetal heartbeat is not seen, it is recommended that the woman be rechecked in 1-2 weeks. If the fetal heartbeat is still not seen and the HCG is abnormal, the presence of fetal failure should be considered. It is recommended to follow up the examination under the supervision of the doctor to clarify the development of the fetus.