Level 1: How many months into pregnancy do you start to produce milk? The first few months of pregnancy when milk production begins is a concern for pregnant women and expectant mothers. Generally speaking, pregnant women will start to produce milk around 3-4 months after pregnancy, but this varies from person to person. Some expectant mothers may experience breast swelling and pain, lactation, etc. early in pregnancy, while others may not have obvious lactation reactions until close to delivery. The reason why milk is produced is because in the early stages of pregnancy, hormone levels in women begin to change, including increased secretion of estrogen and progesterone. Under the influence of these hormones, breast cells begin to proliferate