Prolactin

Prolactin is naturally elevated during breastfeeding to stimulate milk production. Outside of lactation, elevated prolactin (hyperprolactinemia) can suppress GnRH pulsing, reducing FSH and LH secretion and disrupting ovulation. It is checked in the evaluation of irregular cycles and infertility.

Causes of high prolactin include a benign pituitary tumor (prolactinoma), certain medications (antipsychotics, metoclopramide), hypothyroidism, and stress or recent exercise before the blood draw.

Treatment with dopamine agonists (cabergoline or bromocriptine) typically normalizes levels quickly and restores ovulation without IVF in many patients.