Hyperprolactinemia is defined as an increased rate of prolactin in the blood.
There are several reasons for the increase in this hormone. Some of them are related to the inhibition of dopamine, a neurotransmitter that exerts a negative control on prolactin. Therefore, a decrease in dopamine results in an increase in the blood prolactin rate.
On the other hand, an increase in prolactin also influences the secretion of the hormone GnRH, which is responsible for regulating the production of the pituitary hormones FSH and LH. As a consequence, high prolactin levels cause anovulation in women and infertility.