In early pregnancy, pre-miscarriage manifestations such as vaginal brown blood may occur due to various unfavorable factors, such as luteal insufficiency, chromosome number and structure abnormalities, etc.; this is similar to the small amount of brown blood on the first day of menstruation in some women, and it is difficult to distinguish only by this symptom, and women in early pregnancy usually have a series of symptoms such as menopause, early pregnancy reaction, frequent urination, breast changes, etc. Its diagnosis also requires blood HCG (human chorionic gonadotropin) and ultrasound are required to confirm the diagnosis. Menstruation refers to the periodic shedding and bleeding of the endometrium that accompanies the cyclical changes of the ovaries; under the regulation of estrogen and progesterone, the endometrium is divided into the proliferative phase, the secretory phase and the menstrual phase (the days we call menstruation, usually 3-5 days, with a small amount of dark red blood at the onset of menstruation, which later increases to bright red, with the normal menstrual blood volume not exceeding 80ml). Women in early pregnancy will have a series of clinical manifestations; such as menopause: it is the earliest symptom in the early stage of pregnancy. For women of childbearing age who have normal sexual life, if they usually have regular menstruation, once the menstrual period reaches more than 10 days (10 days of menopause), pregnancy should be highly suspected. Early pregnancy reaction: such as cold, dizziness, weakness of limbs, drowsiness, nausea and vomiting, dislike of greasy and sour food, etc., mostly appear about 6 weeks after menopause and disappear on their own about 12 weeks. Frequent urination: The enlarged uterus presses the bladder in front of it in the pelvic cavity causing the pregnant mother to have the urge to urinate. Breast changes: Self-perceived breast swelling and pain, gradual enlargement of breast volume, enlarged nipple areola, deepening of coloring, and may develop Montserrat nodules (dark brown nodules around the areola). Clinically, since the symptoms of new pregnancy are usually not obvious, early pregnancy mainly relies on auxiliary tests to clarify whether and when pregnancy occurs: for example, qualitative and quantitative determination of blood HCG, vaginal ultrasound examination, etc.