Usually, the gestational sac can be seen and the fetal heart can be heard on ultrasound if it is more than about 2 cm. Since each baby is not exactly the same, the time of appearance of the fetal heartbeat may vary. For women with a regular menstrual cycle, i.e. 28 days, you can usually see the fetal bud and hear the fetal heart by ultrasound after 42 days of menopause, when the size of the gestational sac is about 2 cm. If the gestational sac exceeds 2.5 cm and there is still no fetal heart and germ on ultrasound, it is an abnormal condition and the pregnant woman needs to have further tests for HCG and progesterone to check if an empty sac or fetal abortion has occurred. Therefore, women should go to the hospital for regular ultrasound examinations in early pregnancy to determine the development of the fetus by monitoring the fetal heartbeat and fetal buds. Once abnormalities are detected, active measures need to be taken for treatment to avoid serious consequences.