During the first month of pregnancy, a woman will experience essentially no clinical symptoms. In the first month of pregnancy, the embryo should be in the stage of just being implanted in the uterine cavity, has not yet developed into chorionic villi, and has not yet begun to release chorionic gonadotropin, and the level of progesterone in the body is high. Because the hormone levels in a woman’s body have just begun to change, there will be no obvious early pregnancy symptoms at this time, and pregnancy can only be detected through early pregnancy tests or blood tests. When menopause is about 40 days, the estrogen level in a woman’s body gradually increases, which will lead to water and sodium storage, causing mild edema of the gastrointestinal mucosa, nausea, vomiting, anorexia and other early pregnancy reactions. Breasts will gradually increase in size, nipples and areolas will become darker in color, and symptoms such as fatigue, dizziness and drowsiness will also occur. Therefore, women will not have obvious symptoms in the first month of pregnancy, and the early pregnancy reaction will appear only when menopause is about 40 days.