Taking birth control pills withdrawal bleeding clean breast swelling, may be a drug-induced reaction, on the other hand, may be caused by breast disease. 1. Drug effects. Contraceptive pills contain a large number of progesterone, can promote breast enlargement, breast swelling, with the extension of time, the drug in the body slowly disappears, the symptoms will gradually improve. 2. Breast disease. If you usually have breast lobular hyperplasia or breast fibroids, there will be breast swelling and pain phenomenon, this situation will not disappear with the extension of time. Therefore, it is best to go to the breast department for examination to exclude organic lesions of the breast. Breast pain, pay attention to rest, do not fatigue, do not stay up all night, so as not to aggravate the condition.