Why is prolactin high and how to treat it?

Raised prolactin has several common causes, and the first step is confirming it is genuinely raised. Prolactin rises transiently with stress, a difficult blood draw, recent breast examination, exercise or sleep, so a single mildly elevated result should be repeated under calm, rested conditions before anything else happens. There is also macroprolactin — a biologically inactive form that some assays measure alongside the active hormone, producing a raised result in someone with no symptoms and no problem. If your level is high but you have normal periods and no other features, ask whether macroprolactin has been excluded. It prevents a good deal of unnecessary investigation. Genuine causes include medications (antipsychotics, some antidepressants, metoclopramide, certain blood pressure drugs), untreated hypothyroidism, and a benign pituitary adenoma called a prolactinoma. High prolactin suppresses ovulation, which is why it causes irregular or absent periods and difficulty conceiving. Management depends entirely on the cause — which is why establishing it comes before treatment. An MRI is arranged where levels are substantially raised or symptoms suggest a pituitary lesion.