This is the first thing to consider: first, there is no possibility of pregnancy, if you have had sex before and did not do protective measures, in the previous period before the breast does not swell or lower abdominal swelling, before the menstruation suddenly appear breast swelling or lower abdominal swelling, to consider the pregnancy. It is best to go to the hospital and have your blood checked for HCG, or human chorionic gonadotropin, in about 10-14 days of sex. Second, cystic hyperplasia of the breast, the typical symptom is that before each period the breast will appear swelling and pain, before the menstruation swelling and pain is obvious, after the menstruation swelling and pain reduced, can do ultrasound clear, treatment can be used to medication and improve lifestyle, such as regular rest, avoid emotional excitement.