The more obvious difference between early pregnancy and premenstrual period is the early pregnancy reaction and changes in the breasts, vagina and cervix. Before menstruation, some women experience discomfort such as a feeling of falling or contraction pain in the lower abdomen and lower back, and symptoms such as diarrhea, headache, and anxiety and irritability. The greater difference between early pregnancy and premenstrual period is manifested by delayed menstruation and early pregnancy reactions characteristic of early pregnancy (lethargy, poor appetite, acidophilia, nausea, morning sickness, etc.), as well as changes in the breasts (breast distension, deepening of the nipple areola, and the appearance of dark-brown nodules around the areola, also known as Montgomery’s nodes), in addition to changes in the vagina and cervix (the mucous membranes of the vagina and the vaginal portion of the cervix are congested with blood in the form of a purplish-blue color). There is a difference between early pregnancy and premenstrual period as mentioned above. When the above characteristic changes occur, it is necessary to go to the hospital in time to have blood HCG and ultrasound examination to make a clear diagnosis of pregnancy, because the symptoms alone cannot fully determine whether it is a pregnancy or not.