Causes of Elevated Prolactin Levels

Prolactin is a polypeptide hormone—also known as lactogenic hormone—secreted by the anterior pituitary gland. During late pregnancy and lactation, prolactin levels rise significantly in women to promote mammary gland development and milk production. In non-pregnant women, serum prolactin levels typically do not exceed 20 μg/L. So, what causes elevated prolactin levels? Below, we address this question.

Causes of Elevated Prolactin Levels

1. Pituitary Tumors

Elevated prolactin is commonly caused by various tumors of the pituitary gland in women. Typical symptoms include breast tenderness, galactorrhea (spontaneous milk secretion), oligomenorrhea (infrequent menstruation), and amenorrhea (absence of menstruation).

2. Medication-Related Factors

Certain medications can elevate prolactin levels. For example, oral contraceptives may increase prolactin secretion while suppressing gonadotropin release from the pituitary. Prolonged use of reserpine, chlorpromazine, or morphine may interfere with dopamine synthesis, absorption, or metabolism—thereby disinhibiting prolactin secretion. Additionally, intense physical exercise, fatigue, and trauma may also transiently elevate prolactin levels.

3. Neural Stimulation

Stimulation of certain body areas—particularly the chest skin—or injury to the thoracic nerves causing severe pain can activate neural pathways that signal the hypothalamus, resulting in increased prolactin secretion.

4. Hypothalamic Disorders

Diseases affecting the hypothalamus or adjacent structures may reduce production of prolactin-inhibiting factor (PIF) or increase secretion of thyrotropin-releasing hormone (TRH) and prolactin-releasing factor (PRF), leading to hyperprolactinemia.

5. Primary Hypothyroidism

When thyroid function declines, the hypothalamus detects insufficient thyroid hormone levels and responds by increasing TRH production. While TRH stimulates thyroid-stimulating hormone (TSH) release from the pituitary, it also concurrently stimulates excessive prolactin secretion—potentially resulting in galactorrhea.

The above outlines the main causes of elevated prolactin levels. Hyperprolactinemia in women may lead to decreased estrogen levels and ovarian dysfunction. If associated symptoms arise, prompt medical evaluation is recommended. We hope this information is helpful to you.