The symptom of breast swelling and pain in early pregnancy is a relatively common normal reaction during pregnancy, and the symptoms gradually disappear around 12 weeks of pregnancy. The possible reasons for the sudden disappearance of the symptoms of breast swelling and pain in early pregnancy include: 1. possible abnormal embryonic development, after the embryo stops developing for various reasons, the levels of estrogen, progesterone and chorionic gonadotropin in the body will drop, the breast tissue will lose the stimulating effect of these sex hormones and become smaller, and the original symptoms of swelling and pain will be significantly relieved or disappear completely. 2. the symptoms of breast swelling and pain The symptoms themselves are not very serious, and as the number of weeks of pregnancy increases, the pregnant woman’s adaptation to various pregnancy reactions is enhanced, so that the original symptoms of breast distension and pain diminish or disappear. The emotional reaction of pregnant women also has an obvious impact on the symptoms of chest pain. When pregnant women are calm and happy, the symptoms of chest pain will be significantly relieved.