B-type ultrasound examination when menstruation does not occur can mainly discharge whether it is caused by pregnancy, and can also generally observe the thickness of the endometrium, whether there are organic lesions, and can also observe ovulation. 1. Observe whether you are pregnant: If a woman who has a normal sex life has a period that does not come, you can clarify whether you are pregnant by ultrasound examination, because a woman will stop menstruating when she is pregnant. If the ultrasound finds a gestational sac in the uterus, pregnancy can be confirmed, otherwise the possibility of pregnancy can be basically excluded. 2. Observe the thickness of the endometrium: the thickness of the endometrium varies when an individual is in different times of the menstrual cycle. By observing the thickness of the endometrium, we can understand when we should have menstruation and whether the endometrium is thin or thick; 3. menstruation and guide the next step of examination and treatment. If women usually have regular menstruation, once the menstruation is delayed, it is recommended to go to the hospital in time, if necessary to do hormone six and other tests to further assess the cause of menstruation, according to the results of the examination to give treatment, so as to restore the normal menstruation.