A prolactin blood test is used to assess hormonal balance in women and men and is prescribed in cases of reproductive system disorders: in women – infertility, menstrual cycle disorders, and polyendocrine metabolic ovarian syndrome (PMOS). In men – erectile dysfunction and infertility.
The hormone prolactin is produced by the pituitary gland, a small gland in the brain that regulates many important processes in the body. Prolactin is most commonly associated with breastfeeding, as it is responsible for the production of breast milk after childbirth. However, prolactin (PRL) also affects reproductive health, the menstrual cycle, conception, sexual desire, emotional well-being, and metabolism, making it an important marker in the comprehensive assessment of the endocrine and reproductive systems.
Prolactin levels may fluctuate. They can be influenced by stress, physical activity, lack of sleep, emotional excitement, and certain medications. Therefore, it is important to prepare properly and follow all recommendations before taking a blood test for prolactin. In some cases, changes in hormone levels may not cause noticeable symptoms for a long time. A person may experience only fatigue, irritability, sleep disturbances, or decreased sexual desire without associating these symptoms with hormonal changes. Timely diagnosis helps identify problems at an early stage.
Prolactin in Women
In the female body, prolactin:
- contributes to the development of the mammary glands;
- is responsible for breast milk production;
- influences the menstrual cycle;
- supports ovulation and fertility;
- affects emotional well-being.
Elevated prolactin levels in women may present as irregular menstrual periods, absence of ovulation, difficulty conceiving, or nipple discharge. Hormone levels may temporarily increase after physical exertion, emotional stress, sexual intercourse, or insufficient sleep. Some women may also experience mood swings, anxiety, or sleep disturbances. Low prolactin levels are less common but may also indicate hormonal disorders.
Prolactin in Men
Prolactin is also important for the normal functioning of the male body. It influences testosterone levels, sexual desire, and fertility.
Elevated prolactin levels may lead to:
- decreased libido;
- erectile dysfunction;
- chronic fatigue;
- difficulty conceiving;
- enlargement of the breast tissue (gynecomastia).
In men, elevated prolactin levels may develop gradually. Often, a person does not immediately notice the changes and only becomes concerned when persistent fatigue, reduced energy levels, or sexual problems appear.
Elevated Prolactin (Hyperprolactinemia)
Elevated prolactin levels (hyperprolactinemia) may be either a temporary physiological condition or a sign of an endocrine disorder. Hormone levels may increase due to stress, intense physical activity, sleep disturbances, or the use of certain medications. In some cases, the cause may be thyroid disease, polyendocrine metabolic ovarian syndrome (PMOS), or benign pituitary tumors known as prolactinomas.
Prolactin: Normal Levels in the Human Body
Prolactin levels depend on age, sex, and physiological condition and may vary depending on the laboratory and testing method used. In women, prolactin levels increase during pregnancy and breastfeeding. Reference values also depend on the test system and equipment used for analysis, which is why normal ranges may differ between laboratories. Current reference ranges are provided directly on the laboratory report.
The timing of prolactin testing is crucial for obtaining accurate results. In women, hormone levels fluctuate throughout the menstrual cycle, making it important to take this factor into account. The optimal time for testing is between days 2 and 5 of the menstrual cycle (early follicular phase). During this period, hormone levels are most stable and best reflect the body's actual condition. In men, the test is best performed in the morning to minimize the impact of daily hormonal fluctuations.
To obtain the most accurate results, it is recommended to:
- have the test performed in the morning, 2-3 hours after waking up;
- avoid stress and strenuous physical activity the day before testing;
- avoid sauna visits and alcohol consumption for 24 hours before the test;
- abstain from sexual activity before the blood draw.
A blood test for prolactin is an important component of the comprehensive evaluation of endocrine and reproductive disorders. A physician may recommend measuring prolactin together with other hormones, such as TSH, FSH, LH, or testosterone. A comprehensive approach helps determine the underlying cause of symptoms more accurately and assess the overall function of the endocrine system.
