Prolactin

Prolactin 101: Everything you need to know about prolactin

September 23, 2022Hertility

Key takeaways

  • Prolactin is an important hormone that has roles all around the body and within the reproductive system
  • Prolactin has a well-established role within breast growth and breast milk production during and after pregnancy
  • Prolactin imbalances can interfere with our menstrual cycles and ovulation, impacting our fertility and chances of conceiving
  • Testing our prolactin regularly with a hormone and fertility test can help us get to the bottom of menstrual cycle irregularities or fertility issues

A lactation pro, prolactin is yet another super important hormone. 

Prolactin is perhaps best known as the ‘milk hormone’ because of its role in helping our breasts grow and produce breast milk (lactation) during pregnancy and after giving birth. 

But prolactin also has hundreds of other effects throughout our bodies that most of us are totally clueless about. 

So exactly what does prolactin do? Where does it come from? And most importantly, why should we test our prolactin levels?

Let’s get to it…

What is prolactin?

Similarly to follicle-stimulating hormone (FSH), luteinizing hormone (LH) and thyroid-stimulating hormone (TSH), prolactin is mainly made by the small but mighty pituitary gland, in the brain. From there, it’s released into the bloodstream where it travels around the body.

As mentioned, prolactin’s main role is encouraging breast growth and milk production during pregnancy and after we give birth—but it also has important roles in maintaining our metabolism, regulating our stress response, maintaining a functioning immune system and in the development of our reproductive organs. 

No matter if you’re someone who can lactate or not, prolactin is present in everyone, regardless of sex. And in anyone who isn’t currently pregnant, lactating or suffering from a hormone imbalance, prolactin is typically produced in low, steady amounts.

Prolactin imbalances

Just like all of our hormones, from time to time, our prolactin levels can get off balance.

This can cause a whole range of different symptoms and effects throughout the body, including affecting our thyroid hormones, stress hormones, menstrual cycles and ovulation.

High Prolactin Levels

If you’re not pregnant or haven’t just given birth but experiencing abnormally high prolactin levels, this is known as hyperprolactinemia. 

Too much prolactin can stop our brains from producing FSH and LH—two key hormones involved in regulating our menstrual cycles and bringing about ovulation. 

If FSH and LH are affected, ovulation can stop leading to the loss of periods, which is called amenorrhoea. No ovulation means no chance of a pregnancy, and therefore big issues for our fertility.

Disruption to our menstrual cycle can also cause knock-on effects on our oestrogen levels, causing oestrogen deficiency.

Some of the most common symptoms of high prolactin levels to look out for are milky white discharge from the nipples when not breastfeeding (galactorrhea), disturbances to the menstrual cycle, visual disturbances, headaches and symptoms of oestrogen deficiency.

Note: If you are experiencing any form of nipple discharge when not breastfeeding, get this checked by a physician or GP as it can be a symptom of breast cancer.

High prolactin levels can be caused by a variety of reasons, including imbalances in our thyroid and stress hormones. Additionally, a growth or tumour present in our pituitary glands, called a prolactinoma, can also cause persistent or increasing prolactin levels. 

If you’re wondering how to lower prolactin levels, this is very much dependent on the cause of your excess prolactin levels. Your doctor may prescribe you medications like bromocriptine or cabergoline to lower your prolactin secretion. Surgery may also be recommended as the best treatment option for you. Persistently high prolactin that has been caused by chronic stress, over-exercising or poor sleep may be lowered by lifestyle modifications.

Low prolactin levels

On the flip side, low prolactin levels, called hypoprolactinemia, is rare. 

Sometimes there aren’t any obvious symptoms of low prolactin levels, other than not being able to produce or release much breast milk after giving birth.

Breastfeeding can increase our prolactin levels naturally—as the more we stimulate the nipples, more prolactin is produced. 

Why should we test our prolactin levels?

Like all of our reproductive hormones, it’s good to check in with prolactin regularly, especially if we’re trying to conceive or having any problems with our menstrual cycles or experiencing hormonal symptoms. 

Testing our prolactin levels can help us to determine if there are any hormonal issues affecting our fertility or menstrual cycle, or investigate any symptoms of prolactinoma. 

With a Hertility Hormone and Fertility test, we can test your prolactin levels alongside your Anti müllerian hormone (AMH), thyroid hormones and cycling hormones (FSH, LH and oestrogen) to help you gain a full insight into your hormonal health and fertility. 

Prolactin FAQs

Can I get an FSH, LH, Prolactin test all in one?

Luckily, you’re in exactly the right place. With our Hormone and Fertility test we will test you for up to 10 reproductive hormones, including your FSH, LH, prolactin and more. 

Do prolactin levels change with age?

Unlike hormones like Anti Müllerian Hormone (AMH) and oestrogen, our prolactin levels should stay relatively consistent post puberty until menopause, with the exception of when we’re pregnant or breastfeeding. After menopause, prolactin levels tend to be slightly lower. Most hormone tests don’t take into account a normal prolactin level by age, and instead have premenopausal and postmenopausal reference ranges. 

Does prolactin increase breast size?

Yes, increased prolactin levels cause the breasts to grow, which is why when we’re pregnant our breasts usually grow. If we’re experiencing high prolactin levels when we’re not pregnant, this can also cause breast swelling and tenderness.

What are normal prolactin levels?

Reference ranges for what is a normal prolactin level will be specific to the lab that is testing your sample and women are expected to have higher prolactin levels than men. However, in general, prolactin levels are expected to be less than 25 μg/L in those assigned female at birth and not pregnant or breastfeeding

Wanting to find out about your prolactin levels and what your levels mean for your overall health? Well we’ve got you covered. With our Hormone and Fertility Test, you can test prolactin alongside your other reproductive hormones to gain an in-depth understanding of your health and fertility. Take our quick and easy online health assessment to get started today.

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