When there is no fetal heartbeat or buds at 51 days, physical causes can be temporarily observed and then rechecked. When the embryo is underdeveloped, medication is needed to treat it and terminate the pregnancy if necessary. 1. Physiological reasons: In early pregnancy, fetal heartbeat and buds can be seen on ultrasound examination at about 42 days after menopause. However, for women with long menstrual cycle, after confirming pregnancy through urine pregnancy test, due to the time of ovulation and the time of fertilized egg implantation are late, so the appearance of fetal buds and fetal heart will also be late, can be temporarily observed under the guidance of the doctor, and then review the examination in 7 to 10 days. 2. Poor embryonic development: the normal development of the embryo 51 days after menopause has been able to see the fetal buds and fetal heart, but if not detected, and progesterone and blood HCG (human chorionic gonadotropin) levels are low, can be given by the doctor’s instructions to progesterone, heparin and other drugs to protect the fetus treatment, if after treatment and ultrasound let not see the fetal heart, need to terminate the pregnancy in a timely manner. When there is no fetal heartbeat or buds on the 51st day, it is necessary to take timely treatment under the guidance of a doctor, and not to use medication on your own to avoid adverse effects.