Breast swelling and pain during menstruation, but not after pregnancy, is a normal physiological phenomenon, but there is also the possibility that the embryo stops developing. Normally, breast pain during menstruation is mostly due to changes in estrogen levels, and after pregnancy, estrogen levels will also increase, promoting the development of breasts and ducts, and some women will feel breast swelling, but with the increase in the duration of the pregnancy, when adapted to the changes in the body of estrogen after breast swelling symptoms will disappear. However, after pregnancy, when the embryo stops developing, the level of estrogen in the body will also decline, and the breast pain will disappear. Normally, breast swelling and pain during menstruation, but not after pregnancy, it is recommended to regularly check the development of the embryo, no abnormalities do not need special treatment observation can be.