Prolactin Levels Test - Meaning, Purpose & Normal Range

Max Lab

Sep 13, 2022

Prolactin, also known as the lactogenic hormone, is produced by the pituitary gland, which is located at the base of the brain. Prolactin contributes to several bodily functions and is also responsible for lactation, breast tissue development, and milk production. The production and release of prolactin from the pituitary gland is controlled by the brain chemical, dopamine, and the oestrogen hormone. Based on factors like exercise, stress, or nipple stimulation, prolactin can also be produced by the mammary glands, immune system, and central nervous system.

What Does Prolactin Do?

At normal levels, Prolactin plays a role in a number of bodily functions, but its main functions include:

• Milk production, lactation, and breastfeeding
• Development of mammary glands within breast tissue

The Prolactin Blood Test

Higher or lower levels of prolactin can lead to several health issues like low testosterone levels, reduced libido, and erectile dysfunction in men and in women, it can lead to irregular menses, milky discharge from the nipples even if one is not pregnant or breastfeeding, low libido, vaginal dryness, etc. In severe cases, higher than normal levels of prolactin may even lead to infertility. A prolactin test can be performed to measure the level of this hormone in a blood sample. The prolactin levels test may be performed by itself but is generally a part of fertility panel tests like the FSH-LH-Prolactin TSH test or the FSH-LH-Prolactin test, meaning that it is performed along with a number of other tests to help doctors evaluate how well the reproductive organs of an individual are functioning.

The Purpose of the Prolactin Test

The purpose of the prolactin test may vary from case to case. Some of the reasons why a doctor may prescribe a prolactin levels test include:

• Diagnosis of the cause behind infertility, abnormal discharge of breast milk, or irregularities in the menstrual cycle in non-pregnant women and to evaluate lactation failure after childbirth in women.
• Investigating the causes of erection-related issues, abnormal breast discharge, testicular failure, or infertility in men.
• Diagnosing and monitoring the progress of pituitary gland tumours (prolactinoma) in men and women.

Excess prolactin in the blood can interfere with the function of the testicles, reducing the production of sperm and testosterone, meaning that a prolactin test may also be prescribed as a follow-up test for low testosterone levels.

Understanding Abnormal Prolactin Levels

A prolactin test is one for the evaluation of one’s reproductive health or to diagnose and monitor certain medical conditions. In general, having low or high prolactin levels in the blood may not always indicate something serious.

Low Prolactin Levels

The prolactin test showing an individual having lower than normal levels of the hormone indicates a condition called hypopractinaemia, which is generally not much cause for concern. However, depending on the symptoms one is showing, follow-up tests may be ordered to diagnose the underlying condition.

Causes

• Certain medications like bromocriptine or cabergoline (dopamine agonists), ergot alkaloids, and atypical antipsychotics.
• Hypopituitarism or having an underactive pituitary gland, or other pituitary-related disorders.
• Other factors like obesity in gestating women, and abnormal levels of melatonin.

Low levels of prolactin can lead to ovary dysfunction and irregular or absent menses in non-pregnant women; anxiety and an increased risk of developing diabetes in pregnant women or new mothers; metabolic syndrome, reduced sex drive, and erectile dysfunction in men.

High Prolactin Levels

High levels of prolactin or hyperprolactinaemia may be a normal occurrence, or they may have been caused by conditions that require medical attention.

Causes

• Pregnancy
• Breastfeeding
• Prolactinomas or tumours of the pituitary gland
• Underactive thyroid
• Macroprolactinaemia
• Certain medications like dopamine inhibitors, oestrogen, antidepressants, blood pressure drugs, etc.

Symptoms to Look Out For

A prolactin levels test may also be prescribed if an individual is displaying symptoms related to high or low levels of the hormone.

Symptoms of High Prolactin Levels

• Headaches
• Minor loss of vision
• Scanty menses or irregularity/absence of the cycle in women
• Issues with or inability in getting pregnant
• Impotence in males
• Reduced libido
• Breastmilk discharge in men or non-pregnant women
• Delayed puberty
• Erectile dysfunction in men

Symptoms of Low Prolactin Levels

• Headaches
• Body hair loss
• Irregular menses in women
• Lack of lactation in women after childbirth
• Loss of facial hair and growth of breast tissue in men
• Impotence in men
• Lower sex drive
• Slowed growth and development in children 

The Normal Range for the Prolactin Test

The normal range of a prolactin test will be different for men, pregnant women, non-pregnant women, and children. Apart from this, they also vary based on age, health history, and the diagnostics lab where the test is performed. However, in general, normal levels for a prolactin test can be defined as:

• 3-15 ng/mL in men
• 3.2-20 ng/mL in children
• 4-23 ng/mL in non-pregnant women
• 34-386 ng/mL in pregnant women

The results can be affected by the use of certain medications, diseases of the kidney or liver, excessive stress, improper sleep schedule, alcohol consumption within the last 24 hours of taking the test, or heavy exercise just before the test. Even without the presence of such factors, abnormal prolactin results may not always indicate a serious medical issue and may require some follow-up testing for a proper diagnosis.