There are two main reasons why the ultrasound still does not monitor the buds on the 45th day of pregnancy: firstly, the possibility of a vacuolar pregnancy cannot be excluded. The second point is that the ovulation may be late in the current period. If you have high expectations for your child, we suggest that you observe the pregnancy for a while and check the ultrasound again in a week’s time. For women who normally have regular menstruation, the fetal sac can be detected by transvaginal ultrasound around 35 days after menopause, while fetal buds can be seen around 42 days after menopause, and fluctuating fetal heartbeat can be detected around 49 days after menopause. A vacuolar pregnancy is one in which a sac has formed but there is no yolk sac, no buds and no fetal heart, as if a large tree had not borne fruit. If the pregnancy is a vacuolar pregnancy, abortion is recommended. The cause of a vacuolar pregnancy may be related to the abnormal development of the embryo itself.