Prolactin
Prolactin is a hormone made by your pituitary gland, best known for enabling milk production after childbirth. It is present in all sexes and can influence reproductive hormones.
Stress, prandial state, and nipple stimulation elevate values. Specimen drawn after 30 min seated rest. Macroprolactin causes false elevation, confirm with PEG precipitation if asymptomatic hyperprolactinemia.
Beyond lactation, prolactin can affect menstrual cycles, fertility, and testosterone levels, so it is often checked when these are disrupted. Because it rises with pregnancy, breastfeeding, stress, sleep, and certain medications, context is important when reading it.
Elevated prolactin can result from pregnancy or breastfeeding, stress, certain medications, or a benign pituitary growth called a prolactinoma. Because many everyday factors raise it temporarily, a high value is often rechecked before any conclusions are drawn.
Low prolactin is uncommon and usually not a clinical concern on its own, though it can occasionally relate to reduced pituitary function.
Prolactin ranges differ by sex and rise markedly in pregnancy and breastfeeding, and levels vary with time of day and stress. A clinician can advise on ideal sampling conditions and interpret your result.
Sources
Educational context only, not medical advice or a diagnosis. Reference ranges vary by lab, age and sex; always discuss your results with a clinician.