Prolactin is a hormone produced by the pituitary gland, a small organ located at the base of the brain. Its primary function is to stimulate breast development and milk production, particularly during pregnancy and after childbirth. When prolactin levels become abnormally elevated, a condition known as hyperprolactinemia, it can interfere with the body’s normal reproductive processes.
What is Prolactin and Hyperprolactinemia?
Prolactin is a hormone that supports lactation and mammary gland development. During pregnancy, prolactin levels naturally increase, preparing the breasts for milk production. Hyperprolactinemia occurs when prolactin levels are higher than normal in the bloodstream. For non-pregnant and non-breastfeeding women, normal levels are generally below 25 ng/mL. Elevated levels can impact both men and women, though this article focuses on female fertility.
How High Prolactin Impacts Fertility
Elevated prolactin levels can disrupt the female reproductive system, making conception challenging. Prolactin interferes with the release of gonadotropin-releasing hormone (GnRH), which signals the pituitary gland to produce other hormones. This reduces follicle-stimulating hormone (FSH) and luteinizing hormone (LH). FSH and LH are essential for ovarian function, including egg development and release during ovulation. Insufficient FSH and LH can lead to irregular or absent ovulation, known as anovulation.
Causes and Diagnosis of High Prolactin
High prolactin levels can stem from various sources, including physiological changes, certain medical conditions, and medications. A common cause is a prolactinoma, a non-cancerous tumor of the pituitary gland that produces excess prolactin. Other potential causes include an underactive thyroid gland (hypothyroidism) and chronic kidney disease. Certain medications, such as some antipsychotics, antidepressants, and high blood pressure drugs, can also elevate prolactin levels. Stress and excessive stimulation of the chest wall can also temporarily increase prolactin.
Diagnosis typically involves a blood test to measure prolactin levels. If levels are consistently high, further evaluation, such as an MRI of the pituitary gland, may be recommended to identify an underlying cause.
Treatment Approaches for High Prolactin
Treating hyperprolactinemia primarily aims to lower prolactin levels and restore normal reproductive function. Pharmacological treatments are usually the first-line approach. Dopamine agonists, such as bromocriptine and cabergoline, are commonly prescribed. These medications work by mimicking the effect of dopamine, a neurotransmitter that naturally inhibits prolactin release.
By reducing prolactin, dopamine agonists can help normalize FSH and LH levels, leading to the resumption of regular ovulation. For individuals with larger prolactinomas that do not respond sufficiently to medication, or in cases where medication is not tolerated, surgery to remove the tumor might be considered. With appropriate and timely treatment, many individuals with hyperprolactinemia can successfully achieve pregnancy.