High Prolactin Levels – Causes, Symptoms, Diagnosis, Treatment

High prolactin levels can occur due to a variety of reasons. Mildly elevated prolactin – less than 100 ng/ml – usually occurs in conditions which are not serious. However, if your prolactin level is more than 100, it may be due to a serious medical disorder such as a pituitary tumor.

What Is Prolactin?

Prolactin is produced by the pituitary gland. Its level is highest during sleep at night and lowest around noon time. Secretion of prolactin takes place in pulses, usually separated by about 90 minutes.

What Is The Normal Function Of Prolactin?

Prolactin has many functions in the body. For example, it has effects on metabolism, the immune system and blood cell production. However, three main functions of prolactin are:

• Growth of  breasts
• Milk production
• Cessation of menses

Therefore,  prolactin is a hormone that has a tremendous role during and after pregnancy. It is produced in large amounts during pregnancy. In this way  prolactin prepares the breasts for milk production to nourish the newborn. In addition, prolactin in large quantities causes cessation of menses during pregnancy and after delivery for many months. It is nature’s way to prevent another pregnancy too soon,  thus giving enough time for the nourishment of the newborn.

Symptoms Of Elevated Prolactin Levels In Women:

• Infrequent menses or even lack of menses
• A clear or milky discharge from the nipple
• A decrease in all aspects of sexuality: desire, arousal, vaginal lubrication, orgasm and satisfaction
• Weak bones
• Headaches and changes in the field of vision may occur due to a large pituitary tumor

Symptoms Of Elevated Prolactin Levels In Men:

• Decreased libido
• Erectile dysfunction
• Weak muscles
• Weak bones
• Excessive fatigue
• Anemia
• An enlargement of breasts – medically called gynecomastia – may take place. Rarely, clear or milky discharge from the nipple may occur.
• Headaches and changes in the field of vision may occur due to a large pituitary tumor.

What Increases Prolactin?

• Stress
• Breast stimulation
• Orgasm
• Pregnancy
• Hypothyroidism (underactive thyroid)
• Drugs such as estrogen( oral contraceptives), metoclopramide ( brand name, Reglan ), domperidone, verapamil, methyldopa, reserpine, cimetidine (as intravenous), narcotics and many anti-depressants and anti-psychotic drugs.
• Liver disease
• Kidney failure
• Chest wall pain
• Spinal cord lesions
• Pituitary tumor
• Other Pituitary/hypothalamic diseases such as acromegaly, Cushing’s disease, sarcoidosis, metastases, tuberculosis, hemochromatosis, meningioma, head trauma, empty sella syndrome, lymphocytic hypophysitis.
• Radiation to skull

Can Low Vitamin D Increase Prolactin Levels?

It seems vitamin D deficiency may cause high prolactin levels. For example, in a study from Poland, researchers investigated the levels of vitamin D in women who had high levels of prolactin. They found these women to be low in vitamin D.  The researchers, then gave these women vitamin D as 2000 IU per day for four months. Results were amazing! Vitamin D lowered prolactin in this group of women.¹

So, there seems to be an interesting relationship between vitamin D and prolactin: low vitamin D may increase prolactin and vitamin D supplement may decrease prolactin level.

Can Low Vitamin B12 Increase Prolactin?

We did a literature search on vitamin B12 and high prolactin levels and found only one case report. In this patient, prolactin level was elevated as 101 ng/mL due to a condition called lymphocytic hypophysitis, which is an autoimmune disorder. Interestingly, vitamin B12 was low in this patient due to  autoimmune gastritis. ²

It does makes sense. This patient had two autoimmune disorders, one caused high prolactin and the other caused low vitamin B12.

So low vitamin B12 does not cause high prolactin, but low vitamin B12 and high prolactin may be present in the same patient coincidentally.

What Is A Normal Prolactin Level?

Normal prolactin level is less than 20 – 25 ng/ml in males and non-pregnant females. During pregnancy prolactin level rises into 100-400 ng/ml.

Diagnostic Tests Of High Prolactin Levels – Hyperprolactinemia

A mild elevation such 20-40 ng/ml may be due to a peak of a normal pulse or due to stress or breast stimulation. Therefore, three levels of prolactin should drawn on three separate days to confirm the diagnosis.

The next step is to find out the cause of the high prolactin level.

A step-by-step approach is important, with special emphasis to rule out pregnancy, drugs and hypothyroidism. Then an MRI of the pituitary area should be obtained to evaluate for a possible pituitary disorder.

What Is The Treatment Of High Prolactin – Hyperprolactinemia?

 Treatment of high prolactin obviously depends upon the cause.

For example, you may be on one of the drugs that can elevate prolactin levels, as mentioned above. Obviously, try to eliminate the drug, but only after consulting with your health care professional. Your doctor may want to prescribe an alternative drug.

Or you may be having hypothyroidism – underactive thyroid. Simply treating underactive thyroid should normalize your prolactin level.

How To Treat Hyperprolactinemia Due To A Pituitary Tumor

There are three treatment modalities for a prolactin tumor.

• Drugs

• Surgery

• Radiation

Drugs are the treatment of first choice in most cases. However, some patients may need surgery or radiation.

Surgery itself does not cure a prolactin pituitary tumor. That’s why these patients need to be on drugs afterwards.

Radiation takes years to be effective. In addition, it may cause serious irreversible damage to the pituitary gland and other structures in the brain.

Obviously, you need to discuss pros and cons of each treatment modality with your physician.

What Are The Drugs To Treat Elevated Prolactin?

• Bromocriptine (brand name, Parlodel)
• Cabergoline ( brand name, Dostinex)

What Are The Side-Effects Of Bromocriptine (Parlodel), Cabergoline (Dostinex)

Side effects from bromocriptine (Parlodel) and cabergoline (Dostinex) include:

• Nausea
• Dizziness
• Weakness
• Low blood pressure upon standing
• Nasal congestion
• Abdominal pain
• Constipation.
• Rarely hallucinations can also occur

In Summary:

A high prolactin level can be due to a variety of reasons. You need an experienced endocrinologist for proper evaluation and treatment.

References:

1. R Krysiak 1, B Kowalska 1, W Szkróbka 1, B Okopień 1.  The association between macroprolactin levels and vitamin D status in premenopausal women with macroprolactinemia: a pilot study. Exp Clin Endocrinol Diabetes. 2015 Sep;123(8):446-50.
2. https://pubmed.ncbi.nlm.nih.gov/6615105/

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