All you need to know about progesterone

Progesterone is one of the primary female hormones, alongside oestrogen. It plays an essential role in the menstrual cycle and throughout pregnancy. It’s even important for men - for sperm and testosterone production.

But what can your progesterone level tell you about your health?

 

In this article, we cover:

• What is progesterone?
• What does progesterone do?
• Why do I need a progesterone blood test?
• What is a normal progesterone level?
• What level of progesterone indicates ovulation?
• Symptoms and causes of low progesterone
• Symptoms and causes of high progesterone
• How to increase progesterone levels naturally

 

What is progesterone?

Progesterone, often termed the pregnancy hormone, is a type of sex hormone. It is part of a group of steroid hormones called progestogens.

 

Where is progesterone produced?

In women, progesterone is primarily made in the ovaries. But during pregnancy, the placenta also starts producing progesterone to support the growing baby. The adrenal glands (the glands that sit above the kidneys) also produce small amounts.

In men, the adrenal glands are the primary source of progesterone, but the testes also make a small amount.

 

What does progesterone do?

Progesterone has several functions in the body, but one of its main roles is to support pregnancy.

In women, progesterone mainly helps to:

• Regulate the menstrual cycle
• Prepare and maintain the womb lining for a potential pregnancy
• Support the later stages of pregnancy
• Support the growth of the placenta and foetal development

For more information about the role of progesterone in pregnancy, visit our guide to pregnancy hormones.

In men, progesterone is involved in:

• Sperm production
• Testosterone production

Progesterone is also important for sleep and regulating immune responses. It might also have a protective effect on some neurological disorders and osteoporosis [1].

 

Why do I need a progesterone blood test?

There are several instances where your doctor may recommend checking your progesterone levels.

A progesterone test may be used to:

• Determine if you’re likely ovulating (releasing an egg)
• Assess early stages of pregnancy if there are symptoms of an ectopic or failing pregnancy
• Help check the placenta and foetal health during a high-risk pregnancy
• Monitor progesterone levels while on progesterone replacement therapy
• Investigate abnormal bleeding from the womb
• Investigate symptoms of high or low progesterone

Your healthcare professional will interpret your result alongside your medical history, symptoms, and examination findings. Sometimes, you may need additional tests or investigations.

 

What is a normal progesterone level?

Progesterone levels can vary a lot based on factors like age, menstrual cycle stage, and pregnancy in women. Normal ranges also vary significantly according to the lab. You should bear this in mind if you’re testing your progesterone level in different places.

The following table is given as a guide only.
 

Stage		Progesterone level (nmol/L)	Progesterone level (ng/mL)
Menstruation	Pre-ovulation (follicular phase)	<0.6	<0.2
	Ovulation	0.2–13.2	0.06–4.2
	Post-ovulation (luteal phase)	13.1–46.3	4.1–14.6
Pregnancy	First trimester	11–44	3.5–13.8
	Second trimester	25–83	7.9–26.1
	Third trimester	58–290	18.2–91.2

 

What's a normal progesterone level for menopause?

After menopause (postmenopause), a normal progesterone level is typically less than 1.3 nmol/L (0.4 ng/mL).

What's a normal progesterone level for men? 

A normal progesterone level for men is typically less than 1.6 nmol/L (0.5 ng/mL). But progesterone levels aren't usually checked in men unless an adrenal problem is suspected.

 

What level of progesterone indicates ovulation?

Progesterone is sometimes used to check if you’ve ovulated. For an accurate result, it’s important to take your progesterone sample at the right time in your cycle.

An Ovulation Progesterone Blood Test should be taken seven days before your next period. If you have a regular 28-day cycle, you can take the test on day 21. If you have irregular periods, it’s best to take a blood test on day 21 of your cycle and repeat the test every day until your next period starts.

Labs use different reference ranges to determine how likely it is you’ve ovulated. The following ranges are given as a guide.
 

	Progesterone level (nmol/L)	Progesterone level (ng/ml)
Ovulation likely	>30	>9.4
Ovulation possible	15–30	4.7–9.4
Ovulation unlikely	<15	<4.7

 

If you receive an unexpectedly low result, it could mean you’ve not ovulated in that cycle or that you’ve taken your test too early in your cycle (before progesterone levels have peaked).

 

How can I check my progesterone level?

You can check your progesterone level with a blood test at home. We have several options, depending on your reason for taking the test:

• Ovulation Progesterone Blood Test – to check whether you’ve ovulated.
• Pregnancy Progress Blood Test – to check whether your progesterone levels are normal for your stage of pregnancy.
• Oestradiol, Progesterone, and Prolactin Blood Test – mainly for men taking testosterone replacement therapy to assess its effect on general health.

 

Symptoms of low progesterone

Progesterone plays a crucial role in the female reproductive system and overall wellbeing. If levels are too high or too low, it can cause symptoms.

Symptoms of low progesterone include:

• Irregular periods and short cycles
• Premenstrual spotting
• Mood changes, such as anxiety and depression
• Trouble sleeping
• Headaches or migraines
• Possible weight gain (rare)

Low progesterone levels may also make it more difficult to get pregnant. During pregnancy, low progesterone may lead to spotting or, rarely, miscarriage.

Normally, oestrogen and progesterone help to balance each other out. Having low progesterone may lead to oestrogen dominance, which has lots of possible symptoms.

 

Causes of low progesterone

There are many reasons your progesterone level could be low.

Common causes of low progesterone include:

• No ovulation – if no egg is released, there isn’t an empty follicle (corpus luteum) left behind to produce progesterone.
• Polycystic ovary syndrome (PCOS) – PCOS is a condition associated with raised levels of male hormones which can prevent ovulation.
• Underactive thyroid – a longstanding underactive thyroid (hypothyroidism) can affect the hormone axis and reduced progesterone release from the ovaries [2].
• Luteal phase defect (LPD) – when the second half of the menstrual cycle is shorter than it should be (less than ten days), the corpus luteum fails to release enough progesterone. There are several proposed causes of this, including stress, eating disorders, excessive exercise, thyroid disease, and obesity [3].
• Raised prolactin levels – due to the feedback loop, raised prolactin levels can inhibit follicle-stimulating hormone (FSH) and luteinising hormone (LH). This can prevent ovulation from occurring.
• Perimenopause – progesterone levels naturally decline with age and throughout perimenopause.
• Stress and overtraining – stress can affect hormone production by affecting the body’s feedback loop.
• Contraception containing progesterone (e.g. mini-pill, the implant, or injection) – some oral contraceptions contain a synthetic version of progesterone which thickens cervical mucus and prevents ovulation. It also provides feedback to the body to release less gonadotropin-releasing hormone (GnRH), FSH, and LH. The result is that the body produces less progesterone than it naturally would during the menstrual cycle. If you're experiencing side effects or concerned about your contraception options, you may wish to review this with your healthcare provider. 
   

Symptoms of high progesterone

Progesterone levels naturally rise during the second half of the menstrual cycle and may give rise to symptoms.

Symptoms of raised progesterone levels include:

• Breast tenderness
• Tiredness
• Bloating
• Low mood
• Low sex drive
   

Causes of high progesterone

It’s normal for progesterone levels to fluctuate. But consistently raised levels of progesterone or very high levels may indicate an underlying problem.

Possible causes of raised progesterone levels include:

• An ovarian cyst
• Adrenal problems, such as congenital adrenal hyperplasia (CAH)
• Ovarian cancer

During pregnancy, abnormally high levels of progesterone may point to a molar pregnancy or a multiple pregnancy (i.e. more than one baby).

 

How to increase progesterone levels naturally

Wondering how you can boost your progesterone levels?

If your progesterone levels are persistently low (or very low), it’s worth speaking to your GP, especially if you have symptoms. There could be an underlying condition to blame.

Otherwise, there are some natural ways to help support your progesterone levels from home. Note that some of these studies are small-scale and further research is needed to prove any conclusive benefit.

8 natural ways to raise progesterone levels:

1. Reduce chronic stress – one study of 259 women found that high stress levels were associated with reduced luteal progesterone levels, by about 10% [4]. These women were also less likely to ovulate. Here are our top ten ways to de-stress.
2. Get enough vitamin C – vitamin C is an antioxidant which is thought to play an important role in women’s reproductive health. A study of 259 women found that higher vitamin C levels were associated with higher progesterone levels [5]. Another study of 122 women with a luteal phase defect found that supplementing with 750 mg of vitamin C significantly increased progesterone levels by an average of 18.3 nmol/L [6].
3. Get enough vitamin E – a study looked at the effect of taking 600 mg vitamin E supplements daily among a small number of women. Two-thirds of the participants saw an improvement in their progesterone levels [7].
4. Get enough folate – a study of 259 healthy women showed that a higher intake of folic acid supplements was associated with higher progesterone levels in the luteal phase [8].
5. Get enough selenium – though there is limited research in humans, animal studies have shown that selenium supplementation increases progesterone levels [9,10].
6. Treat underlying conditions – Treating conditions such as PCOS, hypothyroidism, and raised prolactin can help to improve low progesterone levels. Our Advanced Female Hormone Blood Test includes biomarkers such as thyroid-stimulating hormone (TSH), testosterone, and prolactin to help check for these conditions.
7. Avoid overexercising – physical activity is great for reducing stress levels, maintaining a healthy weight, and balancing hormones. However, overdoing it can negatively impact progesterone levels, especially during the luteal phase [11].
8. Avoid endocrine-disrupting chemicals (EDCs) – EDCs interfere with the normal function of hormonal systems, including progesterone [12]. EDCs can be found in food and drink containers, plastic wraps, pesticides, and some textiles.

 

Takeaway

Progesterone is a primary female sex hormone for regulating the menstrual cycle, supporting a healthy pregnancy, and overall health. Low levels can affect ovulation, fertility, as well as mood and sleep quality.

A healthy lifestyle and diet can help you support your progesterone levels. But if your levels don’t improve or you continue to experience symptoms, it’s best to visit your GP who may want to rule out other causes or consider other forms of treatment.  
 

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References

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9. Kamada H, Hodate K. Effect of dietary selenium supplementation on the plasma progesterone concentration in cows. J Vet Med Sci. 1998;60: 133–135.
10. Kamada H, Nonaka I, Takenouchi N, Amari M. Effects of selenium supplementation on plasma progesterone concentrations in pregnant heifers. Anim Sci J. 2014;85: 241–246.
11. Kossman DA, Williams NI, Domchek SM, Kurzer MS, Stopfer JE, Schmitz KH. Exercise lowers estrogen and progesterone levels in premenopausal women at high risk of breast cancer. J Appl Physiol (1985). 2011;111: 1687–1693.
12. Impact of EDCs on Reproductive Systems. [cited 22 Nov 2022]. Available: https://www.endocrine.org/topics/edc/what-edcs-are/common-edcs/reproduction