What is progesterone?

What is progesterone?

Progesterone is one of the main female sex hormones. It plays a key role in preparing your body for a potential pregnancy after ovulation. 

Males also produce progesterone — it’s linked to supporting sperm development.

What does progesterone do?

During ovulation, a follicle in your ovary releases an egg. This follicle then forms a temporary mass of cells in your ovary. This is called the corpus luteum, and it’s responsible for producing progesterone.

As your progesterone levels rise after ovulation, it prepares the lining of your womb for a fertilised egg to implant — by stimulating the development of new blood vessels and the release of mucous secretions. This provides a good environment for a fertilised egg to implant. 

If an egg becomes fertilised, the corpus luteum continues to produce progesterone for the first 7-10 weeks of pregnancy.

If you don’t get pregnant after ovulation, the corpus luteum breaks down and your level of progesterone drops. This sudden drop causes your body to shed the thickened lining — your period starts. 

Why is progesterone important for fertility and pregnancy?

If you have low progesterone levels, it can lead to irregular periods. You might also struggle to get pregnant because there isn’t enough progesterone to create the ideal environment for a fertilised egg. 

Having low progesterone levels is also linked to a higher risk of miscarriage — as progesterone helps maintain early pregnancy. 

Signs of low progesterone levels

If your progesterone level is too low, you might experience:

• irregular or absent periods
• spotting during pregnancy
• a history of miscarriages 
• difficulty getting pregnant 

Low progesterone levels can also cause too high oestrogen levels. This can cause symptoms like:

• headaches 
• mood changes
• tender breasts — often with fibrocystic lumps (lumpy or rope-like tissue in your beasts)
• increased symptoms of premenstrual syndrome (PMS)
• bloating 
• a low sex drive

How to test your progesterone levels

You can measure your progesterone levels with a blood test. You can do this with your GP or using a home finger-prick blood test. 

Progesterone tests are most commonly done to check if you’re ovulating. Measuring your progesterone levels when they're expected to peak (7 days before your period), can tell you if you've ovulated or not. This is sometimes called a day-21 progesterone test.

How to improve your progesterone levels

Eating a healthy diet can help increase your progesterone levels, opt for foods rich in:

• magnesium — like pumpkin seeds, brazil nuts, soy, Marmite, and dark chocolate
• zinc — like shellfish, legumes seeds, and nuts
• vitamin B6 — like chickpeas, tuna, salmon, chicken, potatoes, oats, soy, and bananas 
• omega-3 fats (support general hormone production) — like oily fish, chia seeds, flaxseed, and walnuts

Managing your stress levels can also help support your hormone levels.  

If you’re not ovulating and are trying to get pregnant, your doctor might prescribe you medication. For example, clomifene is a medication that’s often used to help stimulate ovulation.