when do u start to get milk in the breast
Breastfeeding Changes early in pregnancy prepare the breast for lactation. Before pregnancy the breast is largely composed of adipose (fat) tissue but under the influence of the hormones estrogen, progesterone, prolactin, and other hormones, the breasts prepare for production of milk for the baby. There is an increase in blood flow to the breasts. Pigmentation of the nipples and areola also increases. Size increases as well, but breast size is not related to the amount of milk that the mother will be able to produce after the baby is born. By the second trimester of pregnancy colostrum, a thick yellowish fluid, begins to be produced in the alveoli and continues to be produced for the first few days until the milk "comes in", around 30 to 40 hours after delivery.[17] [18] Oxytocin contracts the smooth muscle of the uterus during birth and following delivery, called the postpartum period, while breastfeeding. Oxytocin also contracts the smooth muscle layer of band-like cells surrounding the alveoli to squeeze the newly produced milk into the duct system. Oxytocin is necessary for the milk ejection reflex, or let-down, in response to suckling, to occur.[19]