Low progesterone symptoms, causes & treatment

Why is progesterone important?

Progesterone is one of the main female hormones (alongside oestrogen),  which help regulate the menstrual cycle. 

Levels of progesterone change throughout the menstrual cycle. This is how it all works: 

• In the first part of the menstrual cycle, the levels of progesterone are naturally low. 
• After ovulation (release of an egg), something called a corpus luteum is produced. This is a tiny structure that forms on your ovary after you have ovulated. Its job is to make your womb a healthy place for a pregnancy to develop. It does this by releasing progesterone, so progesterone levels rise sharply at this point in your cycle.
• If a woman becomes pregnant after ovulation, progesterone levels stay high and will rise as the pregnancy develops.
• In a menstrual cycle where a woman does not become pregnant, the corpus luteum breaks down and progesterone levels fall in the second half of the menstrual cycle.
• The fall in progesterone levels at the end of the cycle leads to a period, as the womb lining is shed.

There are several symptoms of low progesterone in women. They often relate to changes in the menstrual cycle. Many women notice;:

• Shorter cycles
• Irregular periods
• Spotting in between periods (a sign of low progesterone after ovulation, as the corpus luteum is producing less progesterone)

Sleep disturbances, headaches and mood changes are also sometimes an issue. 

Of course, all of these symptoms can be caused by other medical issues and by other hormonal changes. So it isn’t easy to know exactly what’s going on based on these symptoms alone. 

What causes progesterone to be low? 

Reasons for low progesterone:

• Polycystic ovary syndrome (PCOS)

Women with PCOS sometimes have menstrual cycles in which they do not release an egg (ovulate). Not ovulating means that there is no corpus luteum left behind to release progesterone. So, low progesterone and PCOS sometimes go hand in hand. 

• Under-active thyroid gland 

If the thyroid gland (in your neck) is not producing enough of a hormone called thyroxine, this can lead to a lower production of progesterone in your ovaries.  

• Low cholesterol levels 

Our bodies need cholesterol (found in food) to be able to make progesterone. Therefore, sometimes if cholesterol levels are low, progesterone is also low. 

• High prolactin levels

Prolactin is a hormone produced by the pituitary gland in the brain. If prolactin levels are high, the body’s production of other hormones (such as progesterone) can be suppressed. 

• Perimenopause

When a woman enters the perimenopause, the amount of progesterone produced by her ovaries starts to fall naturally. Low progesterone produces symptoms of perimenopause such as changes in cycle length, which is often one of the first symptoms that women notice in the perimenopause.

Can you test for low progesterone?

A low progesterone test is a blood test. The timing of the blood test is important, as progesterone levels change during the normal menstrual cycle. 

Progesterone levels are usually checked in the second half of the menstrual cycle. If your periods are irregular, this can be more of a challenge, so sometimes other hormones (such as luteinizing hormones or follicle stimulating hormone) are checked instead. 

Checking the progesterone levels in the second half of the cycle is one way to tell if you have ovulated. Basically, a level of progesterone that’s more than 10 ng/ml indicates normal ovulation, but if progesterone is lower than that, it means ovulation didn’t happen or the corpus luteum didn’t produce enough progesterone after ovulation. 

These tests are often done for women who are finding it difficult to get pregnant, alongside other hormonal blood tests¹.

Low progesterone in pregnancy

Good progesterone levels help to maintain the womb lining, which is needed for a healthy pregnancy². 

• Some studies have suggested that having a low progesterone might increase the risk of miscarriage in the first trimester³ (the first twelve weeks of pregnancy). 
• For this reason, healthcare professionals may treat women who have had a miscarriage with progesterone in the early stages of pregnancy if they have any bleeding.

However, progesterone is not the only important hormone involved in maintaining a pregnancy. It’s a complex issue, and it is a very small proportion of women who require additional progesterone to be able to carry a pregnancy. There isn’t enough research evidence yet to know whether progesterone reduces the risk of miscarriage in women who have not suffered a miscarriage before⁴.  If you’re worried about low progesterone in pregnancy, talk to your doctor. 

How to treat low progesterone 

You may be reading this and thinking that your symptoms align with low progesterone. If so, it is important to speak to your doctor first to have all the causes tested for..

Medical treatment options to increase progesterone include: 

• Oral progestogen-only pills (the mini pill) which are contraceptives and will prevent pregnancy
• Vaginal pessaries containing progesterone for fertility or pregnancy treatment
• Hormone replacement therapy (HRT) – often offered to women in perimenopause and menopause

If you think your progesterone levels may be low and are looking for a way to fix this naturally, you could try modifying your diet. There isn’t a lot of research in this area, but here are a few pointers that may help;

• Foods containing vitamin B6 (poultry, oats, bananas, milk)⁵ , may increase progesterone levels
• Foods high in vitamin C (citrus fruits, broccoli, peppers, strawberries)⁶
• Foods high in magnesium and zinc including (green leafy veg, nuts and seeds)⁷. 

Of course, as with managing any hormonal issue, sleeping well, managing stress levels and maintaining healthy levels of exercise are also very important. 

Progesterone is an important hormone in the female body. When it’s out of balance, it can affect your health and menstrual cycle.

If you are not sure whether low progesterone is the cause of the symptoms you are experiencing, speak to your doctor. It is important to have some tests to find out what is causing the symptoms so that you can get the right support.