Many patients are tested for infertility and found to have increased prolactin, and further tests for increased prolactin reveal pituitary tumors. So what is the relationship between the 3? Are all hyperprolactinemia caused by pituitary tumors? Is it necessary to cure pituitary tumor in order to get pregnant? Professor Kemin Li of the Department of Gynecology and Endocrinology at Peking University First Hospital was interviewed to answer your questions.
Increased prolactin in women can lead to infertility First of all, Prof. Li reminded that there are three different measurement units for prolactin (PRL) test reports in different hospitals, commonly used as ng/ml, mIU/L, or nmol/L. The laboratory testing methods and measurement units applied in each hospital are different, so patients should identify them clearly and pay attention to the measurement units and the reference values of the testing hospitals.
Prolactin (PRL), also known as prolactin, is one of the many hormones secreted by the pituitary gland. Prolactin levels in the serum of non-pregnant women should be less than 25ng/ml, or less than 1.14nmol/L, or less than 500mIU/L. In addition, the secretion of prolactin is affected by many factors and is very unstable, fluctuating greatly from day to day, so two or more tests must be above normal to diagnose hyperprolactinemia.
So is it true that if the prolactin (PRL) is ≥25ng/ml, it will definitely cause infertility? Prof. Li said that if the prolactin is mildly elevated, not more than twice the normal value, it may slightly affect ovarian function and may not necessarily show obvious clinical symptoms, only shortened menstrual cycles and luteal insufficiency, which may not necessarily lead to infertility, but may easily lead to miscarriage after pregnancy. If prolactin is significantly elevated, more than 2 times the normal value, it often affects ovarian function, resulting in menstrual disorders, amenorrhea, overflow, anovulation and infertility. About 20% of clinically infertile patients are found to have varying degrees of increased prolactin.
For women who have irregular menstruation, are not easily able to conceive or are prone to miscarriage, it is important to check sex hormones, including prolactin, before conception.
Pituitary tumors are one of the common causes of high prolactin. The causes of elevated prolactin include hypothalamic disorders, pituitary disorders, hypothyroidism, medications, and idiopathic, temporary failure to detect pituitary or central nervous system disorders.
If you take antipsychotics or antidepressants or antihypertensives for a long time, your prolactin level may be elevated, but it is usually not too high (no more than twice the normal value), and most of them return to normal after a month of discontinuation. If prolactin is >100ng/ml, pituitary prolactin microadenoma can be detected in about 50% of patients; if prolactin is >200ng/ml, pituitary tumor can be detected in almost 100% of patients. Prof. Li suggests that if you find a prolactin >50ng/ml, you should have an MRI of the pituitary gland to detect pituitary tumors. Generally speaking, the higher the PRL level, the larger the pituitary prolactinoma is likely to be, but there is not always a positive correlation.
Therefore, the relationship between infertility, prolactin and pituitary tumor can be understood as follows: one of the causes of infertility may be high prolactin, and one of the causes of high prolactin may be pituitary prolactin glands only.
In the treatment bromocriptine mesylate is undoubtedly the drug of choice. Why is it so? Because bromocriptine not only rapidly reduces the level of prolactin (PRL) in the patient’s blood, but also effectively shrinks pituitary prolactinomas and even eradicates some patients with microadenomas. It can control the disease and restore menstruation and fertility in 70% to 90% of patients with pituitary lactinomas. How exactly do I take bromocriptine? Please see “How to take bromocriptine correctly in patients with hyperprolactinemia”.