Yin ultrasound is able to show pregnancy. Most women have a very regular menstrual cycle, usually 28-30 days, and her ovulation cycle is also relatively regular, ovulating in the middle of two menstrual cycles. Pregnancy can be shown by ultrasound at about 40 days, but it can be shown after 37 days of doing a Yin ultrasound. When doing a negative ultrasound, you will find a round or round-like echogenicity in the uterine cavity with a slightly thicker wall and slightly enhanced echogenicity, which is the gestational sac. After 45 days, the buds growing inside the sac and the pulsations of the fetal vessels can be observed. Ultrasound can also accurately determine ectopic pregnancy, if there is no echoes of the gestational sac in the uterine cavity, but there are echoes of the gestational sac in the left or right adnexal area, and the fetal buds and fetal cardiovascular pulsations can be observed inside, then the diagnosis of ectopic pregnancy can be confirmed immediately. When doing a negative ultrasound, the patient does not have to hold in urine, and the image is clearer than that of a normal ultrasound.