Biochemical pregnancies may result in a slight increase in prolactin, but most often return to normal gradually. A biochemical pregnancy is a pregnancy in which the fertilized egg does not implant and only shows a slight increase in blood HCG (human chorionic gonadotropin) levels, followed by vaginal bleeding similar to menstruation, and then the blood HCG quickly drops to normal. Biochemical pregnancies may also cause a slight increase in prolactin, but this usually returns to normal on its own. Common causes of significantly elevated prolactin include hypothalamic disease (e.g., craniopharyngioma), pituitary disease (e.g., pituitary prolactinoma), hypothyroidism, polycystic ovary syndrome, etc. Ultrasound, pituitary MRI, funduscopic examination, and laboratory tests are needed to identify the cause of the disease and treat it aggressively under the supervision of a doctor.