Breast swelling and pain usually occurs after 6 weeks of pregnancy. From early pregnancy, under the influence of estrogen and progesterone, the breasts gradually increase in size, mainly due to the development and growth of breast ducts and alveoli and the deposition of large amounts of fatty tissue in preparation for lactation. Some pregnant women may feel swelling or occasional tingling in their breasts, and some may see superficial veins filling up under the skin. In addition to significant breast enlargement, some pregnant women may experience nipple and areola coloring, darkening, and hyperpigmentation, which will naturally subside after delivery. The sebaceous glands around the areola may appear enlarged and form small scattered nodular elevations called Montserrat’s nodules. During late pregnancy, especially near the time of delivery, a small amount of yellow fluid will spill from the breast, which is the colostrum.