An ultrasound in early pregnancy can be done to see if the pregnancy is intrauterine, and if it is, if there is a fetal bud and fetal heart development. Because some pregnancies may be fetal abortion or ectopic pregnancy, an ultrasound is needed early in the pregnancy to see if it is normal. If you are at least six weeks pregnant and you still cannot see a gestational sac in the uterine cavity with an ultrasound, then you should be highly suspicious of an ectopic pregnancy and have an HCG and repeat ultrasound. This is because once ectopic pregnancy occurs, there is a risk of rupture of the sac leading to intra-abdominal bleeding and shock, which can seriously endanger women’s health. Therefore, it is meaningful to do ultrasound in early pregnancy, but if it is done too early, it is normal that the pregnancy in the uterine cavity may not be visible on ultrasound.