International Board of Certified Lactation Consultant (IBCLC) Practice Exam

During pregnancy, the surge of progesterone plays a crucial role in preparing the body for lactation and supporting the growth and development of the mammary glands. Progesterone stimulates the proliferation and differentiation of glandular tissue in the breasts, leading to the formation of structures necessary for milk production. This includes the development of alveoli, which are the milk-producing cells, and the overall enlargement of breast tissue.

While other types of tissue, like muscle or adipose tissue, may also undergo changes during pregnancy, the specific and significant effect of progesterone is most pronounced in glandular tissue. It is the key hormone responsible for driving these specific adaptations in the mammary glands, in anticipation of breastfeeding. Therefore, the answer regarding the stimulation of glandular tissue aligns with the physiological changes that occur during pregnancy and reflects a fundamental aspect of how the body prepares for postpartum lactation.