Prolactin Levels and Testing

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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.

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.

It is unclear what role prolactin plays in men, but abnormal results have been clearly linked to infertility and sex drive.

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 but 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. If a result is abnormal your physician may ask you to repeat a fasting Prolactin; abstaining from food and sexual activity for a prescribed time before the test is repeated.

Testing Prolactin Levels

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

High prolactin levels inhibit secretion of FSH, which is the hormone that triggers ovulation. So, 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 excretes excess prolactin in your body.

Rarely, high levels of prolactin may cause liver disease, kidney disease, polycystic ovary syndrome (PCOS), shingles, or hypothyroidism.

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, it’s important to find out what is causing the irregularity and to try to treat it. The solution 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.

Dr. Alan Copperman is a board-certified reproductive endocrinologist and infertility specialist with a long history of success in treating infertility and applying fertility preservation technologies. He serves as Medical Director of Progyny, a leading fertility benefits management company, and co-founded and serves as Medical Director of RMA of New York, one of the largest and most prestigious IVF centers in the country. Dr. Copperman is also the Vice Chairman and Director of Infertility for the Icahn School of Medicine at Mount Sinai, and Chief Medical Officer of Sema4, a health information company. Dr. Copperman has been named to New York magazine’s list of Best Doctors 17 years in a row. He has been recognized by his peers and patient advocacy organizations for his commitment to patient-focused and data-driven care. He has published more than 100 original manuscripts and book chapters on reproductive medicine and has co-authored over 300 scientific abstracts on infertility, in vitro fertilization, egg freezing, ovum donation, and reproductive genetics.