In most cases, breast swelling in early pregnancy lasts for about 3-4 months and gradually decreases after the third month of pregnancy, while breast enlargement, swelling and pain, and darkening of nipples are normal. In the early stage of pregnancy, due to the increase in the level of estrogen and progesterone caused by the development of mammary ducts and alveoli, breast swelling, so pregnant women will appear the performance of breast swelling and pain, is a kind of early pregnancy reaction, do not worry too much. Generally, breast swelling can start to appear about 6 weeks after pregnancy, and gradually reduce after 3 months, lasting about 3-4 months in total, but for some insensitive pregnant women, the duration of breast swelling may only be about 1 month. It is recommended that pregnant women should strengthen the local care of their breasts during pregnancy, wash them with water every day, and choose loose cotton underwear. If breast swelling and pain are particularly pronounced in early pregnancy, it is recommended to go to the hospital for a breast ultrasound to rule out the possibility of other lesions.