Besides pituitary tumors, what other causes can lead to elevated pituitary prolactin levels?

Not all elevated prolactin levels are caused by pituitary tumors. In fact, many cases of high prolactin levels are unrelated to pituitary tumors. Sometimes, certain medications can lead to increased prolactin levels in women. For example, the antihypertensive drug reserpine has this side effect. Additionally, women may experience elevated prolactin levels during pregnancy and breastfeeding. Therefore, elevated prolactin does not necessarily indicate a pituitary tumor.