Days 1-7 of pregnancy are generally defined as 4-5 weeks of pregnancy, and if you pay more deliberate attention to the changes in your body, you may experience the following subtle changes in response. Days 1-7 of pregnancy are counted from the last menstrual period, 1-7 days after the next normally calculated menstrual cycle. Clinical weeks of pregnancy often refers to a very regular menstrual cycle. Theoretically speaking, a menstrual cycle of 28 days once, 7 days of pregnancy should be 35 days, that is, 5 weeks, there may be the following subtle reactions. 1. Soreness and swelling in the lower abdomen: similar to the usual feeling before menstruation, a bit of lumbar pain, abdominal swelling, etc. This is a manifestation of the enlargement of the uterus. 2. Breast swelling and pain: similar to the usual menstrual feeling. 3. Frequent urination: the frequency of urination is more frequent, but the amount of urination each time is not much, it is just the feeling of frequent urination, not the real increase in the amount of urine. Many people will have some subtle changes, these are a normal reaction during early pregnancy, do not worry too much. Patients who experience these changes can go to the hospital for relevant examinations to determine whether they are pregnant.