Prolactin is a hormone produced by the pituitary gland that is responsible for stimulating mammary gland development, promoting breastmilk production in the breasts and regulating the menstrual cycle after childbirth.
High prolactin levels can occur with excessive stimulation of the breasts or with the use of specific medications. Symptoms of abnormal levels include leaking milk from the breasts, infertility and decreased libido.
If you suspect you may have high prolactin levels, you are advised to consult an endocrinologist. The doctor may order a prolactin blood test to confirm whether this hormone is high or low.
Why it's ordered
The prolactin test is normally ordered when the patients presents with symptoms of high prolactin, such as irregular menstruation, leaking milk from the breasts in the absence of pregnancy or breastfeeding, infertility, decreased libido and, in men, erectile dysfunction or gynecomastia.
What it's for
The main functions of prolactin in the body are:
- Stimulate mammary gland development
- Promote milk production in the breasts after the baby is born
- Regulate menstruation after childbirth, helping to prevent a new pregnancy during the breastfeeding period.
Furthermore, it is believed that prolactin also plays a role in regulating the body's metabolism. It can impact weight management, bone formation and hair growth.
Interpreting results
In general, the reference values for prolactin in the blood are:
- Non-pregnant women who are not breastfeeding: 2.8 to 29.2 ng/mL;
- Pregnant women: 9.7 to 208.5 ng/mL;
- Postmenopausal women: 1.8 to 20.3 ng/mL;
- Men: below 20 ng/mL.
However, prolactin reference values may vary from lab to lab, therefore, it is important to pay attention to the reference values indicated in the test report
High prolactin level
High prolactin levels, or hyperprolactinemia, can be caused by normal conditions, such as pregnancy, breastfeeding, exercise, breast stimulation or sex. It is is not always considered a health condition.
However, it can also be caused by hypothyroidism, use of antipsychotic medications, polycystic ovary syndrome or brain tumors. It is important to identify the underlying cause to begin appropriate treatment.
Low prolactin level
Low prolactin levels can occur due to the use of some medications or abnormal pituitary functioning . However, low prolactin doesn't typically cause symptoms or health conditions