The lack of chest swelling and pain during pregnancy is a normal manifestation, and is related to endocrine secretion. Since individuals have different constitutions and different endocrine secretions, the clinical symptoms manifested are different. In most cases, after pregnancy, affected by endocrine, there will be chest swelling and pain, nausea, vomiting, drowsiness, weakness and other pregnancy reactions, but some patients do not have chest swelling and pain in the early stage of pregnancy, but will have chest swelling and pain in the middle and late stage of pregnancy, which will also be accompanied by breast milk secretion. This situation varies from person to person, do not be too nervous, usually try to pay attention to hygiene, pay attention to washing, keep the local dry and clean, wear loose cotton underwear, conducive to blood circulation, avoid underwear too tight affect blood circulation, resulting in breast swelling and pain.