Prolactin Levels

Prolactin is a hormone that plays a role in fertility by inhibiting follicle stimulating hormone (FSH) and gonadotropin-releasing hormone (GnRH), the hormones that trigger ovulation and allow eggs to develop and mature.

Prolactin (also called luteotropic hormone) is also associated with the production of breast milk.

It is unclear what role prolactin plays in men, but it is clearly linked to infertility.

Why Would You Have Prolactin Levels Checked?

You would have your prolactin levels checked if you or your partner is having trouble becoming pregnant.

If you are a woman, you might also have your prolactin levels checked if you have stopped having your period or have any abnormal nipple discharge.

When Are Prolactin Levels Checked?

You can have your prolactin levels checked at any point in your menstrual cycle. Prolactin levels vary throughout the day, however. They are highest while you are asleep and first thing in the morning, so the test is usually done about three hours after you wake up.

Testing Prolactin Levels

A prolactin test measures the amount of the hormone prolactin in your blood.

High prolactin levels inhibit secretion of FSH. Therefore, if your prolactin levels are high, your ovulation may be suppressed. This is why women who are breastfeeding (and thus have high levels of prolactin) usually don’t become pregnant.

These high prolactin levels are often caused by prolactinoma, which causes a tumor to grow on your pituitary gland. This tumor then excretes excess prolactin in your body. Rarely, liver disease, kidney disease, polycystic ovary syndrome (PCOS), shingles or hypothyroidism may cause high levels of prolactin.

Several common problems may also affect prolactin levels. Strenuous exercise, lack of sleep, and some foods and medications (especially some anti-depressants and painkillers) can raise prolactin levels. Your health care provider may give you information about how to prepare for the test so that the impact of these factors will be minimized.

Prolactin Levels and Fertility

If your prolactin levels are abnormal, the most important thing is to find out what is causing the irregularity and to try to treat it. It could be as simple as stopping particular prescription drugs you are taking, or could involve treating an underlying condition such as hypothyroidism. Your fertility doctor will work with you to discover and address any underlying problems with the hope of resolving your infertility. If elevated prolactin levels are brought down, the chances of pregnancy are usually excellent.