The precursors of pregnancy include cessation of menstruation, early pregnancy reaction, breast changes, and elevated blood HCG level. 1. Cessation of menstruation: Healthy women with a history of sexual intercourse in their reproductive years and regular menstruation should be highly suspicious of pregnancy if menstruation stops for more than 10 days. 2. Early pregnancy reaction: coldness, dizziness, fatigue, aversion to oil and grease, vomiting in the morning and other symptoms may appear around 6 weeks after the menopause. 3. Breast changes: conscious breast swelling and pain, sebaceous gland hyperplasia around the areola appearing dark brown nodules, called Montessori nodules. 4. Increased blood HCG level: Increased blood HCG level can occur after pregnancy. If the above manifestations occur, you should go to the hospital in time. If pregnancy is diagnosed, you should have a prenatal examination in time to rule out the presence of pregnancy diseases.