Prolactin is a hormone produced by the pituitary gland, the pea-sized gland near the base of the brain that controls metabolism, growth, and sexual development. Although prolactin is produced in small amounts in both males and non-pregnant females, its main role is to stimulate lactation (milk production) in females during pregnancy and maintain milk supply during breastfeeding. A prolactin test measures the amount of this hormone in the bloodstream.
In a woman who breastfeeds, the nursing baby's demand for milk actually controls the mother's supply. When a baby sucks at the breast, the woman's pituitary gland releases more prolactin into her blood, increasing her milk production. If a mother doesn't breastfeed, her prolactin levels will return to normal shortly after giving birth.
Sometimes, though, prolactin levels are elevated even if a woman isn't pregnant or breastfeeding, or in a male. The most common cause is a prolactinoma, a usually benign (not cancerous) prolactin-producing tumor of the pituitary gland.
Doctors may order prolactin tests to help diagnose, or monitor treatment of, prolactinoma. Symptoms of a prolactinoma include headaches, vision problems (if tumor growth is causing pressure on an optic nerve), and galactorrhea (milk production outside pregnancy or breastfeeding, or in a male).
The prolactin test also may be used as part of a work-up for irregular menstrual periods, fertility problems, some types of thyroid or adrenal gland dysfunction, anorexia, and polycystic ovarian syndrome.
All these conditions can be associated with altered prolactin levels. A number of medications and drugs can also stimulate the pituitary gland to release more prolactin into the blood.
No special preparations are needed for this test. However, since prolactin levels vary throughout the day and night — they're highest during sleep, just after waking up, following strenuous exercise, and during periods of emotional stress — your doctor may request that the test be performed at a certain time of day (often a few hours after waking up). You also should be sure that the doctor knows about any medications or drugs your child may be taking, since some may increase prolactin levels in the blood.
It may help to have your child wear a T-shirt or short-sleeved shirt on the day of the test to make things faster and easier for the technician who will be drawing the blood.
A health professional will draw the blood from a vein after cleaning the skin surface with antiseptic and placing an elastic band (tourniquet) around the upper arm to apply pressure and cause the veins to swell with blood. A needle is inserted into a vein (usually in the arm inside of the elbow or on the back of the hand) and blood is withdrawn and collected in a vial or syringe.
After the procedure, the elastic band is removed. Once the blood has been collected, the needle is removed and the area is covered with cotton or a bandage to stop the bleeding. Collecting the blood for the test will only take a few minutes.
Collecting a blood sample is only temporarily uncomfortable and can feel like a quick pinprick. Afterward, there may be some mild bruising, which should go away in a day or so.
The blood sample will be processed by a machine. The results are commonly available in 1-2 days.
The prolactin test is considered a safe procedure. However, as with many medical tests, some problems can occur with having blood drawn, including:
Having a blood test is relatively painless. Still, many children are afraid of needles. Explaining the test in terms your child can understand might help ease some of the fear.
Allow your child to ask the technician any questions he or she might have. Tell your child to try to relax and stay still during the procedure, as tensing muscles and moving can make it harder and more painful to draw blood. It also may help if your child looks away when the needle is being inserted into the skin.
If you have questions about the prolactin test, speak with your doctor. You can also talk to the technician before the procedure.
Reviewed by: Yamini Durani, MD
Date reviewed: July 2014
|American Medical Association (AMA) The AMA has made a commitment to medicine by making doctors more accessible to their patients. Contact the AMA at: American Medical Association|
515 N. State St.
Chicago, IL 60610
|National Eating Disorders Association The NEDA is a nonprofit association dedicated to the prevention and treatment of eating disorders. Contact them at: National Eating Disorders Association|
603 Stewart St.
Suite 803 Seattle, WA 98101
|American Academy of Pediatrics (AAP) The AAP is committed to the health and well-being of infants, adolescents, and young adults. The website offers news articles and tips on health for families.|
|Polycystic Ovarian Syndrome Association The Polycystic Ovarian Syndrome Association has a website just for teens, which includes discussion boards, chats, mentors, and other forms of support.|
|Lab Tests Online This non-commercial site was developed by laboratory professionals to educate caregivers, patients, and patients' families about lab tests.|
|Polycystic Ovary Syndrome In polycystic ovary syndrome, the ovaries produce higher than normal amounts of certain hormones, which can interfere with egg development and release. Learn how doctors diagnose and treat PCOS.|
|Blood Test (Video) These videos show what's involved in getting a blood test and what it's like to be the person taking the blood sample.|
|Menstrual Problems For a girl, getting her first period is a sign of becoming a woman. But it can also be confusing, particularly if she encounters certain menstrual problems like irregular periods or PMS.|
|Endocrine System Although we rarely think about them, the glands of the endocrine system and the hormones they release influence almost every cell, organ, and function of our bodies.|
|Getting a Blood Test (Video) A blood test might sound scary, but it usually takes less than a minute. Watch what happens in this video for kids.|
|Eating Disorders Eating disorders are common among teens and kids, especially young women. Read about the warning signs, prevention strategies, and ways to help a child with an eating disorder.|
|A to Z: Anorexia Nervosa Learn about anorexia nervosa, a type of eating disorder.|
|Eating Disorders Eating disorders are so common in America that 1 or 2 out of every 100 students will struggle with one. Find out more.|
|Thyroid Disease The thyroid gland manufactures the hormones that help control metabolism and growth. So if your thyroid isn't operating properly, you can have problems in other parts of your body.|
|Irregular Periods Wondering whether it's normal to have irregular periods? Get the facts about this common problem.|
What to expect when coming to Akron Children's
For healthcare providers and nurses
Residency & Fellowships, Medical Students, Nursing and Allied Health
For prospective employees and career-seekers
Our online community that provides inspirational stories and helpful information.