Why is Prolactin Low? Causes, Symptoms, and What to Do

Prolactin is a hormone primarily associated with lactation, or milk production, in women. While it plays a crucial role during pregnancy and breastfeeding, both men and women produce prolactin. Low levels of this hormone can impact various bodily functions and may be a sign of underlying health issues.

What is Prolactin?

Prolactin is a hormone produced by the pituitary gland, a small gland located at the base of the brain. It is essential for milk production in women after childbirth. In addition to its role in lactation, prolactin influences reproductive health and the immune system in both men and women.

Check your own value in the calculator above

Why Low Prolactin Matters

Prolactin levels can vary based on several factors, including sex and physiological conditions. For men, about 15 ng/mL is a common upper limit of the reference range, so values below it are usually normal rather than low. For non-pregnant women, about 25 ng/mL is a common upper limit of the reference range, and a low result is one below the lower limit printed on your lab report. During pregnancy, prolactin levels naturally rise to support milk production and other pregnancy-related changes. A low prolactin level can affect reproductive health and may indicate an issue with the pituitary gland or other health concerns.

Causes of Low Prolactin

There are several potential causes of low prolactin levels:

• Pituitary Disorders: Damage or dysfunction in the pituitary gland can lead to decreased production of prolactin.
• Certain Medications: Some medications, particularly dopamine agonists such as cabergoline or bromocriptine, can lower prolactin levels.
• Hormonal Imbalances: Reduced overall pituitary function (hypopituitarism) can lower prolactin together with other pituitary hormones.
• Chronic Illness: Long-term illness is not a typical cause of low prolactin; kidney or liver disease more often raises prolactin.

Symptoms of Low Prolactin

Symptoms of low prolactin can vary, but may include:

• Infertility: Difficulty in conceiving can be associated with low prolactin levels.
• Menstrual Irregularities: Irregular or absent cycles are more typical of high prolactin, so they usually point to other causes when prolactin is low.
• Reduced Milk Production: After childbirth, low prolactin levels can lead to insufficient milk production.
• Low Libido: A decrease in sexual desire can occur in both men and women.

Frequently Asked Questions

What are normal prolactin levels? Normal prolactin levels vary: for men, values up to about 15 ng/mL are typical, and for non-pregnant women, values up to about 25 ng/mL are typical; a low result is one below the lower limit on your lab report. During pregnancy, higher levels are normal.

Can low prolactin affect fertility? The link between low prolactin and fertility is not well established; irregular cycles and problems with ovulation are more typical of high prolactin.

What can cause low prolactin levels? Low prolactin can be caused by pituitary disorders, certain medications, hormonal imbalances, and chronic illnesses.

When to see a doctor

If you experience symptoms such as irregular menstrual cycles, difficulty conceiving, or low milk production after childbirth, it may be helpful to consult a healthcare provider. They can evaluate your symptoms and may recommend testing to assess prolactin levels and identify any underlying conditions.

Decisions about your health should always be made in consultation with your healthcare provider.