When a woman has difficulty conceiving or experiences repeated pregnancy loss, the focus often turns to the uterus, the quality of the embryos or ovarian reserve . However, hormones, too, can play an important role, and one hormone that deserves attention is prolactin.
When true hyperprolactinaemia is confirmed, dopamine agonist medications such as cabergoline or bromocriptine are effective at normalising prolactin levels in most cases. Prolactin is produced by the pituitary gland and is best known for its role in breast milk production. Its levels naturally rise during pregnancy and breastfeeding. Outside these periods, however, persistently elevated prolactin, a condition known as hyperprolactinaemia, can interfere with normal reproductive function. The relationship between elevated prolactin and recurrent pregnancy loss is documented in clinical literature but described with appropriate caution. The guideline recommends prolactin testing in women with recurrent pregnancy loss who also present with irregular periods or unexplained breast discharge. The clinical nuance here is important. Hyperprolactinaemia is one contributing factor among several more established causes of recurrent pregnancy loss, such as chromosomal abnormalities in the embryo, uterine structural issues, antiphospholipid syndrome, and thyroid dysfunction . This does not reduce the clinical relevance of elevated prolactin, but it does mean that a single elevated test result should not be treated as the explanation before other causes have been assessed. Research has demonstrated successful restoration of ovulation and term pregnancy outcomes in women with hyperprolactinaemia following dopamine agonist therapy, including in cases involving pituitary tumours. The condition, when properly identified and treated, is one of the more manageable contributors to fertility challenges.
A 2025 guideline published in the Journal of Obstetrics and Gynaecology Canada found that elevated prolactin is associated with pregnancy loss and may contribute to luteal phase deficiency. The 2025 guideline is explicit on this: elevated prolactin should be confirmed through repeat testing before any treatment is initiated, and thyroid function should be checked first, as hypothyroidism can independently raise prolactin levels.
Hyperprolactinaemia is not considered a clinical manifestation of PMOS, and the two conditions are assessed and managed independently. Some research has found a mean hyperprolactinaemia prevalence of 11.9% in women with PMOS, though the range across studies is wide, reflecting how variable the relationship is across different populations and diagnostic thresholds.
Among women with PMOS, earlier known as PCOS, mildly elevated prolactin levels are occasionally found alongside the more typical hormonal pattern of the condition.
