Small intrauterine sacs can not determine intrauterine pregnancy. Before 35 days of menopause, ultrasound can often detect echogenic areas in the uterus, at this time there is no yolk sac, fetal buds, and intrauterine fluid need to be identified, can not be 100% confirmation of intrauterine pregnancy. Generally 38 days after menopause in the uterine cavity ultrasound detected yolk sac or fetal heart buds, no pregnancy outside the uterus, can confirm the diagnosis of intrauterine pregnancy. If you are pregnant, it is important to know whether the pregnancy is intrauterine, because ectopic pregnancy is a common gynecological emergency, and in severe cases, shock can occur, endangering the life of women. Women who are pregnant, such as abdominal pain and vaginal bleeding and other discomforts, should consult the obstetrics and gynecology department in a timely manner to rule out ectopic pregnancy, in order to avoid serious consequences.