Can high prolactin be linked to repeated pregnancy loss or PMOS?

Persistently elevated prolactin, a condition known as hyperprolactinaemia, can interfere with normal reproductive function. Image used for representational purposes only | Photo Credit: Getty Images 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.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 symptoms are not always obvious. Some women may have irregular or absent periods, difficulty conceiving or an unexpected milky discharge from the breasts. Others may have no noticeable symptoms at all.Prolactin and fertilityReproductive hormones work as a closely connected system. Prolactin is part of this system, and when its levels remain elevated, it can interfere with the hormonal signals required for ovulation.High prolactin can suppress the release of gonadotropin-releasing hormone from the brain. This can subsequently affect Luteinising Hormone (LH) and Follicle Stimulating Hormone (FSH), which are involved in follicle development and ovulation. As a result, some women may ovulate irregularly or stop ovulating altogether. Their periods may become longer, unpredictable or absent, making conception more difficult.Prolactin also interacts with reproductive hormones after ovulation. This is one reason why its possible role in the early stages of pregnancy has attracted clinical attention, although the relationship is more complex than simply linking one abnormal hormone level to pregnancy loss.The link to repeated pregnancy lossThe relationship between elevated prolactin and recurrent pregnancy loss is documented in clinical literature but described with appropriate caution. 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 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. 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.The connection with PMOSAmong women with PMOS, earlier known as PCOS, mildly elevated prolactin levels are occasionally found alongside the more typical hormonal pattern of the condition. 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. Hyperprolactinaemia is not considered a clinical manifestation of PMOS, and the two conditions are assessed and managed independently.Why the elevationThe causes of elevated prolactin are varied. A benign, prolactin-secreting pituitary tumour called a prolactinoma is among the more significant causes and is identified through an MRI when prolactin levels are substantially elevated. Hypothyroidism, certain medications including antipsychotics and some antihypertensives, and occasionally stress or intensive exercise can also raise prolactin levels transiently. This is why repeat testing under standardised conditions such as fasting and avoiding physical stress before the blood draw, is important before a diagnosis of hyperprolactinaemia is established.When true hyperprolactinaemia is confirmed, dopamine agonist medications such as cabergoline or bromocriptine are effective at normalising prolactin levels in most cases. 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.What women should knowFor women experiencing recurrent pregnancy loss or difficulty conceiving, prolactin testing is a reasonable part of a comprehensive hormonal evaluation. The results need to be interpreted alongside thyroid function, ovarian reserve, and a full assessment of both partners, because the factors that influence reproductive outcomes are rarely operating in isolation.(Dr. Prachi Benara is a fertility specialist at Birla Fertility and IVF, Gurgaon. prachi.benara@birlafertility.com) Published - September 16, 2026 04:17 pm IST