Women do not need to abstain from sex before having a negative ultrasound, but if other tests or examinations are combined at the same time, they need to abstain from sex for about 2-3 days according to their examination items. Compared with the abdominal ultrasound, the negative ultrasound can more conveniently and more clearly display the uterus, endometrium and bilateral ovary morphology, size and follicle, blood flow changes, and the diagnostic results are more accurate. Clinically, it is often used to monitor the size of follicles, ovaries and uterus with or without organic diseases. The vast majority of semen left behind after intercourse will be eliminated from the body, so intercourse before the examination will not have an impact on the diagnosis of negative color ultrasound imaging. However, if you need to do secretion smear and other tests, such as leukorrhea routine, mycoplasma culture, or cervical cancer screening, TCT, HPV, etc., you need to prohibit coitus 2-3 days before the examination, so as not to affect the accuracy of the examination results.