High prolactin levels are one of many causes of infertility. Infertility can be a tremendous disappointment for couples desiring children. It can cause stress and treating it can be expensive. There are many causes of infertility but there is one that affects fertility in both women and men and that is high prolactin levels. Another cause of fertility in women that we have written about is related to high FSH levels.
What is Prolactin?
Prolactin is a hormone made in the anterior pituitary gland. The pituitary gland is pea size gland that sits at the bottom of the brain and close to the optic nerve and sphenoid sinus. Prolactin aids in breast development and stimulates milk production by the breasts after childbirth.
Normally small amounts of prolactin circulate in the bloodstream in both men and women. After a baby is born there is a sudden drop in estrogen and progesterone in women follow by a significant elevation of prolactin. The elevated prolactin level stimulates the production of milk for breastfeeding. Milk production outside of pregnancy is called galactorrhea and can be seen in men as well as women.
Most of us have normal prolactin levels. But a small number of women and men have elevated prolactin levels called hyperprolactinemia. Hyperprolactinemia is reserved for abnormal high prolactin levels in non-pregnant women and men – not the elevated prolactin levels following the birth of a child.
High Prolactin Levels and Infertility
In women hyperprolactinemia interferes with normal estrogen and progesterone production leading to irregular and/or missed periods and anovulation. In men hyperprolactinemia leads to decrease testosterone production and impaired sperm production. It also can cause erectile dysfunction and decreased male libido.
Prolactin levels are routinely obtained during the course of an infertility work-up.
Causes of High Prolactin Levels
There are several causes of high prolactin levels. These include:
- pituitary tumors called prolactinomas
- low thyroid function
- some medications uses to treat depression, high blood pressure, and psychiatric disorders (see list below)
- stress including physical stress from excessive exercise
- some foods and herbal supplements (feneugreek, fennel, and red clover)
- nipple stimulation
Drugs that Cause High Prolactin Levels
Any drug that suppress dopamine function or production can potentially cause elevated prolactin levels. There are several drug classes that can blunt dopamine function and include:
- antipyschotics: risperidone, chlorpromazine, perphenazine, haloperidol, metoclopramide, α-methyldopa, and reserpine.
- H2 antagonists used to treat peptic ulcer or esophageal reflux: ranitidine and cimetidine.
- Imipramines used to treat depression: amitriptyline and amoxapine
- Some SSRIs used for depression: fluoxetine (Prozac)
- Calcium channel blocker used for hypertension: verapamil
- Others: estrogen and thyroid releasing hormone
Prolactinomas are benign tumors of the pituitary. They are either called microadenomas when less than one centimeter in size or macroadenomas when greater than one centimeter in size. They either cause symptoms due to their effects on other hormones or due to their size. Macroadenomas can compress the optic nerve leading to peripheral vision loss or cause enough pressure to trigger headaches. But, some prolactinomas cause no symptoms and do not require any treatment and can be followed by regular MRI scans to monitor size and growth.
Treatment of Hyperprolactinemia
Treatment of high prolactin levels depends on the cause. In the case of low thyroid simply restoring thyroid levels to normal with thyroid replacement will lower prolactin to normal levels. If hyperprolactinemia is related a medication then a change in medication can be considered when possible. Foods and herbs known to cause high prolactin levels should be eliminated.
Prolactinomas can be usually managed with medications called dopamine agonists which shut down prolactin production. There are two dopamine agonists used – bromocriptine and cabergoline. Parlodel is the brand name for bromocriptine and Dostinex is the brand name of cabergoline.
In cases where bromocriptine and cabergoline are ineffective or cause side effects (nausea, lightheadedness, and mental fogginess) surgery can be performed to remove the adenoma. Radiation is rarely used and usually reserved when there is residual tumor following surgery in the face of still elevate prolactin levels.
Hyperprolactinemia is a very treatable cause of infertility in men and women. If you suspect you may have it ask your doctor to order a prolactin level.