High Prolactin and Infertility: Test and Treatment
High prolactin levels in women may cause infertility. Not all women need treatment. Accurate testing is critical. Learn about high prolactin levels from a fertility expert.
I have gotten several questions asking me to discuss the hormone prolactin. How to diagnose high prolactin levels in women and when to treat. Many women being treated for high prolactin levels are being treated unnecessarily.
What is prolactin?
Prolactin is the name given to a group of hormones that are produced by the pituitary gland. That's right! Prolactin isn't just one hormone but a group of hormones.
Prolactin has many different roles throughout the body. Perhaps the most important role of prolactin is to stimulate milk production in women, after the delivery of a baby, and to help with the release of milk when the baby is nursing.
During the first few months that a woman is breastfeeding, the high prolactin levels also serve to block ovulation. This is the reason why women who are breastfeeding do not get their periods and therefore do not get pregnant as often.
As time goes on however, the prolactin levels do not stay as high with breastfeeding and the women may start to ovulate.
High prolactin levels may cause infertility in women
Women who are not pregnant and are not breastfeeding should have low levels of prolactin. If a non-pregnant woman has abnormally high levels of prolactin, it may cause her difficulty in becoming pregnant.
High prolactin may block ovulation
Prolactin may cause infertility in several different ways. First, prolactin may completely stop a woman from ovulating. If this occurs, a woman may stop getting her period.
In less severe cases, high prolactin levels may make ovulation less frequent. Women in this category may experience infrequent or irregular periods.
High prolactin may cause luteal phase defect
Women with the mildest cases involving high prolactin levels may ovulate regularly but not produce enough of the hormone progesterone after ovulation. This is known as a luteal phase defect.
Deficiency in the amount of progesterone produced after ovulation may result in a uterine lining that is less able to have an embryo implant. Some women with this problem may see their period come a very short time after ovulation.
There is no evidence that high prolactin levels will interfere with your ability to get pregnant if you are doing IVF. There is also no evidence that high prolactin levels will increase your risk for miscarriage.
Symptoms of high prolactin
Women with high prolactin levels may not have any noticeable symptoms. Some women with high prolactin levels may have no periods or have irregular or infrequent periods.
Another common symptom is breast discharge.
How to test prolactin
Prolactin can be measured with a simple blood test drawn at the fertility doctor's office. In order to get accurate results, prolactin should be drawn first thing in the morning and ideally soon after a period has started and before ovulation.
Women should have had nothing to eat from the night before and they should avoid any stimulation of the breast or nipples from the day before.
Remember earlier when I said that prolactin is actually a group of hormones? This becomes really important now because when your doctor does that blood test, she is measuring all of the types of prolactin in your blood.
Different types of prolactin (some don't need treatment!)
Even though only one type called monomeric prolactin causes problems.
It is really really important if your total prolactin level is high, to follow that up with another blood test to look at your monomeric prolactin.
You only need to be treated if your monomeric prolactin is high. Many of my patients ask why we don't do the monomeric prolactin test first. The reason is is that it is a more expensive test to do and most women won't need it. If your total prolactin is normal so is your monomeric prolactin.
Think of the first test as a screening test. If your screen is abnormal, then you do the more accurate test to see if it is real or not. If your total prolactin level is high and your monomeric prolactin is normal, you do not need treatment.
Causes of high prolactin levels
There are many different causes for high prolactin levels once you have a diagnosis, your doctor should do a thorough search for these before starting treatment. This can include problems with your thyroid, medications you're taking or even a small cyst in your pituitary gland called an adenoma.
The good news is that if you do have high levels of monomeric prolactin, treatment with medication is very effective at returning your levels to normal, getting ovulation to occur and getting you pregnant.