Milk flow in the fourth month of pregnancy is normal and is related to endocrine secretion. This is because after pregnancy, there is an increase in estrogen or progesterone, which leads to the expansion of the mammary glands and the production of milk. During this period, there is also breast enlargement, there is obvious local capillary expansion, and with the increase of pregnancy week, the color of the areola will deepen, the areola will also expand, and there will be Montserrat nodules on the nipple, these are physiological manifestations, do not be too nervous. The actual fact is that you should pay attention to keep your breasts clean, dry and hygienic, and avoid squeezing them with your hands, which can lead to nippitis or mastitis, and you should also pay attention to wearing loose underwear to facilitate blood circulation and reduce the pressure on the local breast tissue.