Macroprolactinemia: a mini-review and update on clinical practice

Area of Science:

• Endocrinology
• Reproductive Medicine

Background:

• Hyperprolactinemia is a frequent endocrine cause of infertility, affecting 15%-20% of women with oligomenorrhea.
• Elevated prolactin (PRL) can suppress the hypothalamic-pituitary-gonadal axis, disrupting reproductive function.
• Human prolactin exists as monomeric, dimeric, and macro-PRL (big-big PRL), with macro-PRL being a high molecular weight form.

Purpose of the Study:

• To highlight the prevalence and diagnostic challenges of macroprolactinemia.
• To emphasize the importance of differentiating macroprolactinemia from true monomeric hyperprolactinemia.
• To advocate for routine screening of macro-PRL in patients with elevated prolactin levels.

Main Methods:

• Review of existing literature on prolactin variants and their clinical significance.
• Analysis of the prevalence of macroprolactinemia in hyperprolactinemic patients.
• Discussion of diagnostic implications and management strategies.

Main Results:

• Macroprolactinemia is identified in 10%-46% of patients with hyperprolactinemia.
• Macroprolactinemia can lead to misdiagnosis, resulting in unnecessary pituitary imaging and dopamine agonist therapy.
• Distinguishing macroprolactinemia from monomeric hyperprolactinemia is critical for appropriate patient management.

Conclusions:

• All patients with persistently elevated prolactin levels should be screened for macro-PRL.
• Accurate diagnosis of macroprolactinemia prevents iatrogenic complications and ensures appropriate infertility treatment.
• Early identification of macroprolactinemia improves patient outcomes in reproductive endocrinology.