International Board of Certified Lactation Consultant (IBCLC) Practice Exam

Which hormone is primarily responsible for stimulating milk production in lactating women?

1. Estrogen

2. Oxytocin

3. Prolactin

4. Progesterone

The correct answer is: Prolactin

Prolactin is primarily responsible for stimulating milk production in lactating women. This hormone is secreted by the anterior pituitary gland and plays a crucial role in the development of mammary glands during pregnancy and in the production of milk after childbirth. During breastfeeding, when an infant suckles, the release of prolactin is stimulated, promoting milk synthesis and secretion in the alveoli of the breast. Therefore, a higher level of prolactin is essential for maintaining an adequate milk supply. While estrogen and progesterone have roles in preparing the breast for lactation during pregnancy, their primary functions are not to stimulate milk production postnatally. Oxytocin, on the other hand, is significant for milk ejection or "let-down" rather than production. Understanding the specific roles of these hormones highlights the unique contribution of prolactin to the lactation process.