Pregnancy breasts will get bigger. After pregnancy, the secretion of estrogen and progesterone in the body will increase, and estrogen and progesterone act on the breast ducts, breast follicles and breast lobules. This encourages the proliferation and development of breast follicles and lobules, resulting in the gradual enlargement of the breasts, increase in the color of the nipple and areola, and the appearance of Montgomery’s nodes around the nipple, which will be accompanied by different degrees of breast swelling and pain. In the middle and late stages of pregnancy, the breast follicles and lobules begin to secrete milk, and breast enlargement will be more obvious. Some pregnant women will have white milk secretion from their nipples in preparation for breastfeeding after delivery. If you breastfeed after delivery, your breasts will continue to grow in size until the end of breastfeeding due to milk secretion. If you do not breastfeed after delivery, your breasts will gradually return to their pre-pregnancy state as estrogen and progesterone decrease.