From the Research
A low prolactin level in non-pregnant women is generally considered to be below 5 ng/mL (or below 5 μg/L in SI units). Prolactin is a hormone produced by the pituitary gland that primarily stimulates milk production in women after childbirth. While much attention is given to elevated prolactin levels, low levels can also be clinically significant. Normal prolactin ranges for non-pregnant women typically fall between 5-25 ng/mL, though reference ranges may vary slightly between different laboratories.
Key Points to Consider
- Low prolactin levels are relatively uncommon but may be associated with pituitary insufficiency, certain medications (particularly dopamine agonists), or conditions affecting the hypothalamus.
- Symptoms of low prolactin are often subtle or absent but might include infertility, decreased libido, or irregular menstruation in some cases.
- If low prolactin is detected, further evaluation of pituitary function may be warranted, especially if other pituitary hormones are also affected.
- A recent study 1 found an association between low prolactin levels and type 2 diabetes, highlighting the potential clinical significance of low prolactin levels.
Evidence Review
The most recent and highest quality study on this topic is from 2024 1, which found that low prolactin levels are associated with an increased risk of type 2 diabetes. While this study did not specifically define a cutoff value for hypoprolactinemia, it suggests that low prolactin levels may have clinical significance.
Clinical Implications
In clinical practice, a low prolactin level in a non-pregnant woman should be evaluated in the context of the patient's overall clinical presentation and medical history. Further evaluation of pituitary function may be warranted if low prolactin is detected, especially if other pituitary hormones are also affected.