International Board of Certified Lactation Consultant (IBCLC) Practice Exam

Which hormone is primarily responsible for milk production?

1. Oxytocin

2. Prolactin

3. Estrogen

4. Progesterone

The correct answer is: Prolactin

The hormone primarily responsible for milk production is prolactin. This hormone is secreted by the anterior pituitary gland and plays a crucial role in the lactation process. During pregnancy, prolactin levels rise, preparing the mammary glands for milk production. After childbirth, the presence of the baby suckling stimulates the release of more prolactin, which sustains milk production throughout the breastfeeding period. Prolactin works by promoting the development of glandular tissue in the breasts, essential for producing milk. Without sufficient prolactin, milk synthesis would be inadequate, leading to challenges in breastfeeding. Oxytocin, while important in the breastfeeding process, primarily facilitates milk ejection or the let-down reflex rather than the production of milk itself. Estrogen and progesterone are also significant in the overall development and functioning of the breasts during pregnancy but do not directly stimulate milk production in the same manner as prolactin. Thus, prolactin is recognized as the key hormone for milk production in lactating individuals.