If your breasts suddenly stop swelling and you don’t have a period, it may be due to the following reasons. The first reason is pregnancy, embryonic dysplasia or embryonic cessation of development, which can be diagnosed clinically with the results of blood HCG monitoring. The second reason is that the condition occurs only when you are about to have your period. If the estrogen secretion in your body is relatively strong before your period and the progesterone secretion is relatively low, you will have breast swelling and pain. Before menstruation, estrogen and progesterone drop respectively, so there will be no pain in the breasts suddenly. It is recommended to observe the breasts for 24 hours and most of them will have menstruation 24 hours after this condition.