Raised Prolactin: Causes, Symptoms, Levels and Treatment

Raised prolactin refers to an elevated level of the hormone prolactin, which plays a central role in regulating lactation and the health of the reproductive system. It is estimated that over 66% of women suffering from galactorrhoea and menstrual disorders such as amenorrhoea have hyperprolactinaemia, that is, an elevated prolactin level. 

This is not a condition in its own right, but rather a signal that something is going on in the body at a hormonal or physiological level that warrants medical investigation. The good news: once the cause has been identified, a raised prolactin level can usually be treated effectively. Let's take a closer look at what elevated values mean, what effects they have and how to bring them back to normal.

What is raised prolactin (hyperprolactinaemia)?

Prolactin is a hormone produced by the pituitary gland. It plays an essential role in milk production after birth, in hormonal balance and in functions relating to reproductive health, such as regulating ovulation and the menstrual cycle. When the level of this hormone in the blood rises above the range considered normal, this is known as hyperprolactinaemia. The explanation is simple:

• Prolactinaemia refers to the concentration of prolactin in the blood.
• The prefix "hyper-" means "in excess".
• Hyperprolactinaemia is simply the term for too much prolactin in the blood.

Because of the role prolactin plays in lactation and the reproductive system, excessively raised levels can lead to changes in menstruation, fertility problems and disruption of other hormonal functions. Statistics show that hyperprolactinaemia is present in 15–20% of women with menstrual disorders and in 30–40% of women with infertility.

But why does the prolactin level rise in the first place? Dopamine release plays a key role. Normally dopamine acts – as the specialist literature confirms – as an inhibitor of prolactin secretion. It travels from the hypothalamus to the pituitary gland and conveys the signal that limits prolactin release. If this signal is weakened or blocked, for example by the influence of oestrogen or because of disorders of the pituitary, the gland may release too much prolactin.

What are the consequences of excessive prolactin production? Prolactin belongs to the network of hormones that play a role in regulating the menstrual cycle and ovulation. An imbalance can therefore affect fertility and the regularity of menstruation. At the same time, it can reduce the production of oestrogen, which in turn may contribute to vaginal dryness, loss of libido and cycle disturbances.

Normal values for prolactin (ng/ml)

Depending on sex, age, pregnancy and, of course, the laboratory carrying out the analysis, the normal range for prolactin levels differs from patient to patient.

As a rough guide, the following reference values in ng/ml apply to prolactin:

• In men: below 20 ng/ml.
• In non-pregnant women: below 25 ng/ml.
• In pregnant women: up to 400 ng/ml.
• In children: between 3 and 20 ng/ml, depending on age and stage of development.

Prolactin may also be reported in mIU/l. If needed, you can convert the figures yourself: 1 ng/ml corresponds to roughly 21 mIU/l.

Since reference ranges for prolactin can vary from one laboratory to another, a normal prolactin value in women should primarily be assessed using the figures given on your own test report.

• A mildly or moderately raised value of up to around 100 ng/ml may have common and temporary causes – such as stress, physical exertion or various medicines.
• Very high values above 200–250 ng/ml are often due to a prolactinoma, a tumour we will come to a little later in this article.

Does that mean that if your prolactin value is, say, three times higher than normal, you must automatically assume there is a disease? Not necessarily. The result must always be interpreted in the context of your symptoms and any medicines you are taking. Depending on the case, your doctor may recommend further investigations.

Causes of raised prolactin – why it occurs

Pregnancy, breastfeeding, stress and intense physical activity are all factors that can influence prolactin levels. In fact, pregnancy, breastfeeding and certain drug treatments are among the most common causes of raised prolactin. What conclusions can we draw from this?

The causes of raised prolactin can be physiological in nature – in which case they are often temporary and normal – or of another kind. Sometimes prolactin levels rise in response to particular medicines.

The cause may also be pathological, in the context of conditions that produce very high prolactin values. A prolactinoma, for instance – a benign tumour of the pituitary gland – can push levels to any height, whereas the other causes rarely exceed 200 ng/ml.

Physiological causes (normal, temporary)

Often the causes of raised prolactin in women are simply normal bodily responses that do not indicate any disease at all. Pregnancy and breastfeeding, for example, naturally stimulate prolactin secretion.

Stress – whether physical or emotional – is another example in this category. Prolactin and stress are closely linked in that stress signals the brain to lower dopamine levels, which normally inhibit prolactin release. By the same principle, intense exercise and lack of sleep can temporarily raise hormone levels.

Medication-related causes

There are also medicines that can raise prolactin levels – likewise by interfering with dopamine. These include antidepressants and antipsychotics, which act on neurotransmitters, medicines for nausea and vomiting, and some blood pressure medications.

Pathological causes (medical conditions)

As already mentioned, very high prolactin values may have pathological causes. Hormonal disorders associated with conditions such as PCOS often go hand in hand with a raised prolactin level, particularly where there are irregular periods or fertility problems.

More serious conditions such as hypothyroidism, kidney or liver failure and a prolactinoma can even lead to values above 200 ng/ml. In hypothyroidism, raised TRH levels can stimulate prolactin secretion, which is why elevated TSH and prolactin values often occur together.

Prolactinoma and the link with other conditions

We promised to look at prolactinoma in more detail. What exactly is it, and how does it relate to raised prolactin? Now is the moment for those answers.

A prolactinoma is a benign tumour of the pituitary gland that produces too much prolactin. Depending on its size, a distinction is made between:

• Microprolactinoma, if it is smaller than 10 mm
• Macroprolactinoma, if it measures 10 mm or more.

The prolactin level itself already provides clues to a prolactinoma. Very high values above 200–250 ng/ml, sometimes up to 400 ng/ml, point more towards a prolactinoma than to other causes.

Does that automatically mean raised prolactin is the same as cancer? No. A prolactinoma is generally benign and does not behave like a malignant tumour. And even when very high values are linked to a prolactinoma, the diagnosis is never made on the basis of blood tests alone. Further investigations always follow.

Raised prolactin and polycystic ovaries frequently occur together. Both can be associated with irregular periods and ovulation disorders. Although raised prolactin is not a cause of polycystic ovary syndrome, if a woman with PCOS has hyperprolactinaemia, her doctor will recommend further investigations.

Raised prolactin in children is rarer and may be linked to certain medicines, hypothyroidism, pituitary disorders or other hormonal problems. Signs of hyperprolactinaemia in children include delayed puberty, absent or irregular periods in girls, slowed growth and headaches.

Symptoms of raised prolactin

Raised prolactin does not always cause symptoms. Sometimes slightly elevated values are discovered entirely by chance during a blood test.

Where symptoms do occur, they are mainly explained either by the imbalance of sex hormones or – in the case of large tumours – by pressure on the surrounding tissue, which can lead to headaches and visual disturbances. The symptoms can affect women and men alike and include:

• Galactorrhoea (milky discharge from the breast without pregnancy or breastfeeding)
• Loss of libido
• Infertility (through effects on ovulation in women and sperm production in men)
• Reduced bone mass
• Headaches
• Visual disturbances

Raised prolactin in women

In women, raised prolactin can affect ovulation and the menstrual cycle, and a certain relationship has been observed between how high the prolactin level is and the symptoms experienced.

At values above 100 ng/ml, amenorrhoea, hot flushes and menopause-like symptoms occur more frequently. With mildly raised values of 50–100 ng/ml, less frequent periods are usually seen.

The most common symptoms of raised prolactin in girls and women are therefore:

• Irregular periods
• Absent periods
• Oligomenorrhoea (infrequent bleeding at intervals of more than 35 days)
• Anovulation (absence of ovulation)
• Galactorrhoea
• Vaginal dryness
• Pain during intercourse
• Loss of libido
• Difficulty conceiving
• Hot flushes and other typical menopausal symptoms

Raised prolactin in men

In men, raised prolactin can lower testosterone levels by suppressing the signals sent from the brain to produce the hormone – which has a direct impact on sexual function. The most common symptoms in men are therefore:

• Erectile dysfunction
• Loss of libido
• Low testosterone levels
• Infertility
• Gynaecomastia (development of breast tissue)
• Galactorrhoea, which is, however, very rare in men.

Raised prolactin, fertility and pregnancy

Because prolactin interacts with the hormones that govern ovulation and a woman's menstrual cycle, hyperprolactinaemia is associated with infertility in many patients. If the prolactin level is too high, ovulation may become irregular or stop altogether, making pregnancy more difficult.

So can you still become pregnant with raised prolactin? The answer is yes, it is possible – but let's look at why. The fact that hyperprolactinaemia affects ovulation does not automatically mean that ovulation stops altogether. Although the chances are lower, some women continue to ovulate and can become pregnant even though their prolactin level is above normal.

If raised prolactin leads to a period without ovulation, conception genuinely cannot occur in that cycle, and hyperprolactinaemia becomes a factor contributing to infertility in women.

The good news: ovulation can be restored by treating the cause and normalising the prolactin level – and the chances of pregnancy then rise again. During pregnancy, prolactin naturally rises once more, preparing the breasts for breastfeeding.

How is raised prolactin diagnosed?

The first step in determining the prolactin level and diagnosing hyperprolactinaemia is a blood test. The test may form part of a hormone profile taken in the follicular phase when cycle disturbances are being investigated.

The results are compared with the laboratory's reference range to confirm whether the prolactin value really is raised. If it is, the doctor will first check the obvious causes: pregnancy, certain medicines, stress or hypothyroidism.

If all of these have been ruled out, the next step may be to measure macroprolactin – particularly in patients with moderately raised values and no symptoms. Macroprolactin is a form of prolactin with reduced biological activity and can explain some raised values in the absence of clinical symptoms.

If the prolactin value remains high and all the above causes have been excluded, the doctor may recommend an MRI scan of the pituitary gland. This can establish whether a prolactinoma or another pituitary lesion is present.

In practice, a very high prolactin concentration can produce a falsely low laboratory result that lies below the true value. This phenomenon is known as the "hook effect" – which is precisely why, in making a diagnosis, your doctor takes into account your symptoms and the results of all investigations rather than the measured prolactin value alone.

Treatment for raised prolactin

Not every diagnosis of a raised prolactin level requires treatment. Whether treatment is needed depends primarily on the cause, on how high the level is and, of course, on the symptoms.

Treatment becomes important, for example, when raised prolactin affects fertility, the menstrual cycle or bone mass. Likewise, treatment is required for large tumours in order to reduce their size and protect vision.

So what treatment options are available when therapy is necessary?

• If the prolactin level is only slightly above the normal range and there are no symptoms, the doctor may simply recommend monitoring the patient and checking the values.
  • The same recommendation may apply in macroprolactinaemia, where the predominant form of prolactin has reduced biological activity.
• If prolactin is raised as a result of taking certain medicines, this is a reversible situation that can be resolved by switching medication or adjusting the dose.
  • In hypothyroidism, the underlying condition is treated, usually with hormone replacement therapy, after which the prolactin level returns to normal.
• If hyperprolactinaemia causes symptoms or is due to a prolactinoma, treatment usually consists of dopamine agonists such as cabergoline or bromocriptine. These mimic the action of dopamine, reduce prolactin secretion and can shrink a prolactinoma.
  • In the rare cases where medicines fail to lower raised prolactin effectively or are not tolerated by the patient, surgery or radiotherapy may be considered.

Can prolactin be lowered naturally? (Foods and home remedies)

Do you have raised prolactin values and want to try normalising them with simple, natural measures first? You can do that, and there are indeed approaches to managing raised prolactin naturally – but it is important to assess the situation realistically and responsibly.

There is no robust evidence that particular foods significantly lower prolactin levels – least of all when the level is raised because of a hormonal imbalance or a medical condition. In such cases, the responsible decision is to see your doctor and stick to the treatment prescribed on the basis of tests and a diagnosis.

General measures that can help you maintain a normal hormonal balance – including prolactin – especially alongside the treatment prescribed by your doctor, are:

• Managing stress: stress can temporarily raise prolactin; relaxation techniques can help here.
• Getting enough rest: lack of sleep can affect prolactin secretion.
• A balanced diet: a varied diet tailored to your own needs supports overall hormonal health.
  • Please note: there are, however, no foods with a proven effect that could serve as a treatment for hyperprolactinaemia.

And what about medicinal plants and teas for raised prolactin? Here too the evidence is limited, and some preparations can even interact with medicines or affect your hormone balance. They should therefore not be used to lower prolactin levels without medical advice. They cannot replace medical investigations or the recommended treatment. If the level remains persistently raised, it is important to speak to your doctor.

Frequently asked questions

Did you know that prolactin is released in pulses and can fluctuate throughout the day? That is precisely why a single raised value is not always enough to determine the cause. It is equally true, though, that a raised result can be worrying and raise many questions. We hope the following answers will help with some of them:

Does raised prolactin make you put on weight?

Raised prolactin is not considered a direct cause of weight gain. However, since hyperprolactinaemia can affect hormone levels, metabolism and appetite, changes in weight are possible.

Does raised prolactin cause hair loss?

Raised prolactin can contribute indirectly to hair loss by altering the balance of sex hormones. Hair loss can, however, have numerous other causes – so raised prolactin is not automatically the definitive explanation.

Does raised prolactin mean cancer?

No, raised prolactin does not automatically mean cancer. Even when the cause is a prolactinoma, this is generally a benign tumour of the pituitary gland.

Can stress raise prolactin levels?

Yes, physical or emotional stress can cause temporary rises in prolactin levels. That is why, if your result is only slightly raised, your doctor may recommend repeating the test under suitable conditions.

What is the link between TSH (thyroid) and raised prolactin?

In patients with hypothyroidism, a raised TRH level can also stimulate prolactin secretion. Elevated TSH and prolactin values can therefore occur together, and the prolactin level may return to normal once the underactive thyroid has been treated.

Can you get pregnant with raised prolactin?

Yes, pregnancy is possible, particularly if the raised prolactin is not preventing ovulation. Otherwise – where hyperprolactinaemia stops ovulation – fertility can return once the underlying cause has been treated.

What does a prolactin level three times above normal mean?

It means the measured value is roughly three times the laboratory's upper limit. This result alone does not determine the cause; it has to be interpreted in the context of symptoms, medicines and further investigations.

How quickly does prolactin fall once treatment begins?

How long it takes for the prolactin value in the blood to normalise depends on the cause and on the particular treatment. Levels may begin to fall immediately after treatment starts, but your doctor will decide when a follow-up test is appropriate and will monitor progress over time.

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