What does lactogenesis I refer to?

Lactogenesis I refers to the beginning of milk production that occurs from mid-pregnancy until about day 2 postpartum. During this stage, the mammary glands undergo significant changes, preparing for milk production. Hormonal influences, particularly from progesterone and estrogen, stimulate the development of milk-producing tissues and the formation of colostrum, the first form of milk that is produced. This phase generally starts around the second trimester of pregnancy and continues until the onset of copious milk production, which is classified as lactogenesis II, typically occurring around two to five days postpartum. Understanding lactogenesis I is vital for midwives and healthcare providers as it informs them about the physiological changes and helps in the education and support of new mothers regarding breastfeeding and the timing of milk production.