Surgery How is prolactin stimulated so it can also stimulate the production of breast milk in return? A Acinar cells start producing colostrum. B Progesterone levels are reduced by the delivery of the placenta. C The letdown reflex takes place. D Progesterone levels increase after the delivery of the placenta. 💡 Explanation How is prolactin stimulated so it can also stimulate the production of breast milk in return? ✓ Correct Answer: B. Progesterone levels are reduced by the delivery of the placenta.