Mammary gland gestation, serum progesterone remains at a stably high concentration so signaling through its receptor is continuously activated. As one of the transcribed genes, Wnts secreted from mammary epithelial cells act paracrinely to induce more neighboring cells' branching. When the lactiferous duct tree is almost ready, "leaves" alveoli are differentiated from luminal epithelial cells and added at the end of each branch. In late pregnancy and for the first few days after giving birth, colostrum is secreted. Milk secretion (lactation) begins a few days later due to reduction in circulating progesterone and the presence of another important hormone prolactin, which mediates
Low milk supply Low milk supply In breastfeeding women, low milk supply, also known as lactation insufficiency, insufficient milk syndrome, agalactia, agalactorrhea, hypogalactia or hypogalactorrhea, is the production of breast milk in daily volumes that do not fully meet the nutritional needs of her infant. Breast milk supply augments in response to the baby's demand for milk, and decreases when milk is allowed to remain in the breasts. Low milk supply is usually caused by allowing milk to remain in the breasts for long periods of time, or insufficiently draining the breasts during feeds. It is usually preventable, unless caused by medical conditions