It is not normal to not see the fetal heart at 6 weeks of pregnancy for those who have regular menstrual cycles, but it is normal for those who have long menstrual cycles and can be rechecked as prescribed by the doctor. In early pregnancy, the intrauterine gestational sac can be seen on ultrasound examination on the 35th day after menopause, and the fetal buds and fetal heartbeat can be seen on the 6th week after menopause. Therefore, for pregnant women with regular menstrual cycles, it is not normal to see no fetal heartbeat at 6 weeks after menopause, and progesterone, HCG (human chorionic gonadotropin) and oestradiol levels can be used to assess the development of the embryo, and fertility preservation treatment can be given as prescribed by the doctor if necessary. For pregnant women with long menstrual cycle, due to delayed ovulation and fertilized egg implantation, the fetal heart may not be detected by ultrasound at 6 weeks of pregnancy, but progesterone and HCG levels are normal, which is normal, and ultrasound can be rechecked once a week as prescribed by the doctor to find out the development of the embryo and to check the gestational week according to the size of the fetal buds. If the fetal heart is not seen on ultrasound at 6 weeks of pregnancy, the cause can be identified under the guidance of the doctor and dealt with in a timely manner.