High prolactin levels (hyperprolactinemia)

ADEMEYI MAXWELL

HORMONES ARE chemical messengers that are produced in one organ and moves through the blood and body fluids to organs and tissues where they are needed to modify and control body functions. Reproductive hormones are one of the factors that contribute to fertility and conception.

Prolactin is one of several hormones that is produced by the pituitary gland. Prolactin has many different roles throughout the body. Perhaps the most important role of prolactin is to stimulate milk production in women after the delivery of a baby. Prolactin levels increase during pregnancy, causing the mammary glands in a woman’s breast to enlarge in preparation for breastfeeding. Prolactin also helps with the release of milk when the baby is feeding.

During the first several months that a woman is breastfeeding, the high prolactin levels also serve to inhibit ovulation. This is the reason why women who are breastfeeding do not get their periods and therefore do not often become pregnant. As time goes on, however, the prolactin levels do not stay as high with breastfeeding and the woman may start to ovulate.

A condition of too much prolactin in the blood of women who are not pregnant and in men is known as hyperprolactinemia. Hyperprolactinemia may also lead to galactorrhea, a condition which causes the breasts to produce milk outside pregnancy.

Prolactin is one of the hormones that control fertility and it is produced by the anterior pituitary gland in the brain. In men, prolactin plays a role in testosterone secretion and in production of sperm cells. In women, prolactin helps to stimulate milk production after the delivery of a baby.

Causes

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Pregnancy and breastfeeding: Usually, a high level of prolactin in the body is considered normal during and after pregnancy, most especially while breastfeeding.

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Prolactinoma: It is a noncancerous tumour of the pituitary gland that causes the gland to produce excess prolactin, thus leading to over-secretion in the blood. This further causes a reduction in the levels of estrogen hormone in the body and it affects ovulation in women. In men, it alters testosterone and compromises sperm production.

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Hypothyroidism and stress: Cortisol and adrenaline are stress hormones. These hormones coupled with excess consumption of carbohydrates cause an imbalance in blood sugar levels. People are at an increased risk of frequent hypoglycemic episodes with an underactive thyroid. In order to activate the thyroid gland, the brain then increases the release of the thyroid-stimulating hormone. Over-secretion of the TSH leads to high prolactin levels.

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Metabolic or hormonal conditions: Another factor that may affect the excess production of prolactin includes damage to other parts of the body. In particular, damage to or illnesses of the kidneys, thyroid and liver can cause hyperprolactinemia. Hyperprolactinemia has also been connected with polycystic ovary syndrome and amenorrhea.

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Medication: Drugs such as antidepressants, antipsychotics, antihypertensive and antinausea medications may increase prolactin levels in the blood.

Symptoms of hyperprolactinemia

• Irregular menstrual periods, change or pause in menstrual cycle

• Anovulation (when an egg is not released during a menstrual cycle)

• Hirsutism (abnormal hair growth)

• Loss of sexual libido, erectile dysfunction and painful sex

• Lactation and pain in breasts

• Headaches and vision change

• Abnormal breast growth (gynaecomastia)

Effect of hyperprolactinemia on fertility in women

Increased levels of prolactin in women can suppress the secretion of the gonadotrophin-releasing hormone. This will in turn affect the release of the luteinising hormone and the follicle stimulating hormone, thus inhibiting ovulation.

Both of these hormones are necessary for the development and maturation of eggs within the ovaries before they can then be released during ovulation and available for fertilisation.

Women with the mildest cases of high prolactin levels may ovulate regularly but may not produce enough of the hormone progesterone after ovulation.

Deficiency in the amount of progesterone produced after ovulation may result in a uterine lining that is less able to have an embryo implant. Some women with this problem may see their period come a short time after ovulation.

Hyperprolactinemia can also interfere with the normal production of other reproductive hormones, such as estrogen. It can stop the ovaries from producing the normal level of estrogen required by the body for regular ovulation and periods. Low estrogen levels in turn can also cause vaginal dryness and low libido.

Effect of hyperprolactinemia on fertility in men

High prolactin levels may affect the production of testosterone which is the major sex hormone in men that regulates fertility. Too little or absence of it may affect normal sperm production in the body, thus leading to infertility.

Men suffering from abnormal prolactin levels may encounter male factor infertility. The issues they may face include poor sperm count, erectile dysfunction and poor libido.

In addition to affecting sex characteristics, high levels of prolactin in men can lead to other problems related to the lack of testosterone.

Fatigue is a common effect of low testosterone, also loss of muscle mass and strength. If left untreated, high levels of prolactin can lead to loss of bone density, which greatly increases the chance of breaking or fracturing a bone.

Treatment of hyperprolactenamia

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Prescription medications such as bromocriptine and cabergoline help the brain produce dopamine to control high prolactin levels.

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Synthetic thyroid hormone: Recommended doses can return the prolactin levels to normal if the underlying cause is hypothyroidism.

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Surgery: In cases where it has become impossible for medication or hormones to treat the tumour, the managing clinician may recommend surgery.

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Radiation therapy: In cases where the tumour cannot be controlled with medication or surgery, radiation therapy is used although this is rare.

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Medications: If medications such as antidepressants, psychosis medications, high blood pressure medications are the causes of hyperprolactinemia, new medications should be prescribed.

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Diet: In addition to taking medications, diet is also important in lowering prolactin levels in the blood. Foods high in zinc and foods rich in vitamin B6 which contains prolactin inhibitors.

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Relaxation techniques such as breathing exercises, massage, music or art therapy can have a major positive effect in lowering prolactin levels for stress-induced hyperprolactinemia.

Most women should not have trouble conceiving once their prolactin levels normalise, as most prolactinomas respond very well to medication. These medications are usually stopped during the course of pregnancy. Hyperprolactinemia may hinder pregnancy if untreated, but it does not permanently cause infertility in both men and women. Once the underlying cause of the high prolactin levels in the blood is diagnosed and effectively treated, the chances of conceiving would greatly improve.

Contact Dr Maxwell at 3631807 or 7575411