What is hyperprolactinemia? – Causes, symptoms and treatments

Hyperprolactinemia is a hormonal disorder that can occur in both men and women. It is caused by excess levels of the hormone prolactin in the blood.

Generally, it is more common to find hyperprolactinemia as a cause of female sterility, as the excess of the hormone prolactin causes alterations in the menstrual cycle and anovulation.

The causes of this disorder are very diverse, ranging from normal pregnancy and lactation to the appearance of benign tumors in the pituitary gland. However, these are ot the only reasons why an excessive increase in blood prolactin levels may occur.

Prolactin hormone

Prolactin (PRL) is a hormone secreted by the pituitary gland, a gland at the base of the brain. Its main function is to stimulate the production of colostrum and breast milk in the mammary glands after childbirth.

Prolactin is also involved in the synthesis of progesterone during the luteal phase of the menstrual cycle.

Although the level of the hormone prolactin usually increases during pregnancy and lactation, it is normal for an adult woman to have values between 0 and 20 ng/ml.

Abnormal blood prolactin levels can alter the menstrual cycle, produce anovulation and, consequently, infertility.

In particular, excess prolactin inhibits the secretion of GnRH (gonadotropin-releasing hormone), which in turn affects the production of FSH and LH hormones, responsible for follicular development and ovulation.

What is hyperprolactinemia?

It is also common for women with polycystic ovary syndrome (PCOS) to have hyperprolactinemia due to increased estrogen production.

Causes of hyperprolactinemia

As we have already mentioned, pregnancy is the main cause of hyperprolactinemia in women. During gestation, the prolactin level may increase to 300 ng/ml.

The same is true during breastfeeding, in which the baby stimulates the nipple when sucking milk causing continuous blockage in dopamine secretion. As a consequence, the decrease in dopamine causes more prolactin to be secreted, as both hormones are regulated by a negative feedback system.

However, these are normal physiological situations in a woman's life in which the increase in blood prolactin is transient, just as it occurs during deep sleep, physical exercise, or orgasm. Once lactation is over, prolactin will return to normal levels and the menstrual cycle will re-establish itself.

Possible causes of hyperprolactinemia

Also, hyperprolactinemia can have some pathological causes, such as the following:

• Hypothyroidism
• Pituitary adenomas (prolactinomas)
• Chronic renal failure
• Polycystic ovary syndrome (PCOS)
• Hyperandrogenism
• Anorexia nervosa
• Stress and anxiety
• Multiple Sclerosis
• Cancer and pituitary tumors

Other causes of hyperprolactinemia

There is also a type of iatrogenic hyperprolactinemia, caused by external factors such as neuroleptic drugs, antidepressants, anxiolytics, tranquilizers, opioids (morphine derivatives), and so on. All these drugs decrease the action and synthesis of dopamine.

Finally, oral contraceptive pills with estrogens may also produce a moderate increase in circulating prolactin in the blood.

Signs and symptoms

Everyone is different and not everyone will have the same symptoms when they have high levels of prolactin in their blood. The following are the most important signs and symptoms of hyperprolactinemia:

• Galactorrhea: secretion of milk by the mammary glands. It occurs in 30% of cases.
• Primary or secondary amenorrhea: disappearance of menstruation.
• Headaches and visual field alterations. These symptoms are caused by tumors.
• Hirsutism, if the woman has PCOS and/or hyperandrogenism.
• Osteroporosis, especially in cases of hypogonadism.
• Decreased libido and dry vagina.
• Infertility, mainly due to chronic anovulation.

Clinical manifestations of hyperprolactinemia

It is not necessary for a woman to have all of these symptoms at once to make a diagnosis of hyperprolactinemia. Sometimes only the most common ones take place.

Furthermore, symptoms in men suffering from hyperprolactinemia include decreased sexual desire, infertility, visual disturbances, galactorrhea and even osteoporosis and decreased muscle mass.

Diagnosis

The first diagnostic test that should be done in any patient with suspected hyperprolactinemia is to meaure bloodprolactin levels.

To do this, a blood test must be done between the third and fifth day of the menstrual cycle, when the ovaries are at rest and hormones at basal levels.

As indicated above, blood prolactin levels greater than 30 ng/ml indicate hyperprolactinemia disorder. If a prolactin result between 20 and 40 ng/ml is obtained, the analysis will be repeated to confirm the diagnosis.

Diagnosing hyperprolactinemia

In addition, it is important to review the medical history of the patient to determine the cause of this hormonal disturbance. Firstly, pregnancy has to be ruled out, and it must be taken into account whether the patient takes oral contraceptives, anxiolytic drugs, antidepressants, etc.

Finally, it is also important to rule out the presence of any pituitary tumor using computed tomography (CT) or magnetic resonance imaging (MRI), especially if hyperprolactinemia is not associated with hypothyroidism.

If the cause of the high prolactin is not found after all tests have been performed, the patient will be told that she suffers from idiopathic hyperprolactinemia.

Treatment

Before starting treatment to lower the level of prolactin in the blood, we need to know the exact cause of this hormonal disorder.

In the case of drugs that are causing hyperprolactinemia, it will be enough to stop taking these substances to restore normal prolactin levels.

If high prolactin is the result of hypogonadism, the endocrinologist may indicate thyroid hormone replacement therapy.

In other situations, such as pituitary adenomas or prolactinomas, the treatment of hyperprolactinemia is based on the administration of dopamine agonist drugs, such as cabergoline or bromocriptine. These substances act like dopamine, inhibiting the production of prolactin in the pituitary gland.

Generally, this type of treatment is the most widely used in order to restore prolactin levels soon and restore fertility, especially in young patients who want to get pregnant. However, a woman can spend months or even years on these medications.

Treatment of hyperprolactinemia with dopamine agonists

If drug treatments do not work, or if large prolactinomas are found, surgery or radiation therapy may be needed to remove the tumor. The latter is less used because it takes a very long treatment for prolactin levels to return to normal.

Hyperprolactinemia and infertility

When the cause of hyperprolactinemina is clear, the best thing to do is to treat the cause in order to get the hormone levels in the blood normalized. In addition, as prolactin levels return to normal, FSH and LH hormone levels will also be regulated. This will restore the woman's ovarian function and reproductive capacity.

However, if the cause of the increased prolactin levels in women is unknown, it will be difficult to establish a specific and personalized treatment.

In these cases, those women diagnosed with hyperprolactinemia and that it is not possible to solve, may have to turn to assisted reproduction techniques to achieve pregnancy.

FAQs from users

Can I get pregnant with high prolactin?

Once the cause of hyperprolactinemia has been determined, prolactin (PRL) is normalised. With proper management, most women can become pregnant.

Bromocriptine and cabergoline are drugs used for treatment and are not teratogenic.

In the case of macroadenomas near the optic chiasma and which do not present a significant reduction in tumor volume with dopamine agonists, the best pre-pregnancy therapeutic option is transsphenoidal surgery.
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Do men also suffer from hyperprolactinemia?

Yes, although it's less common. In this case, a man is considered to have hyperprolactinemia when his blood prolactin hormone level is above 20 ng/ml.

The main clinical manifestations of hyperprolactinemia in men are erectile dysfunction, decreased libido, gynecomastia (an increase in breast tissue) and infertility.

Does Hyperprolactinemia make you gain weight?

That might happen. This is because prolactin hormone irregularities may influence other metabolic pathways related to weight gain.

Can hyperprolactinemia be cured?

This depends on the exact cause that is causing the prolactin hormone surge.

When excess prolactin is due to physiological causes such as pregnancy or breastfeeding, normal levels of this hormone will be restored as soon as the mother stops breastfeeding and recovers her regular menstrual cycles.

If there is a pathological cause, the woman may have to live for long periods of time with hyperprolactinemia. However, dopamine antagonist drugs can help to achieve normal prolactin levels in these cases.

Recommended reading

Apart from prolactin, there are other hormones involved in the female reproductive system that can cause infertility. For more information related to this topic, you can access this article: Female hormone analysis: what should normal hormone levels be?

If you want to know more about breastfeeding and its effect on the menstrual cycle during it, we recommend reading the following post: Feeding your newborn baby - breastfeeding or formula feeding?