Progesterone an important part of hormone replacement therapy for some, but not all women. Here we explain who needs progesterone, why they need it, and the best forms of progesterone.
Progesterone is a hormone released by the ovaries. It prepares the lining of the womb for conception each month. It also regulates the monthly cycle.
During perimenopause progesterone levels bounce around, but decrease over time. These changing progesterone levels can contribute to abnormal menstrual periods and menopausal symptoms.
After menopause progesterone levels continue to decline until they settle at a lower level.
Hormone therapy progesterone is often called progestogens. There are different forms of progestogens women can take.
For women who still have a womb (uterus) it is important to take a progestogen. It should be prescribed alongside oestrogen to make up your HRT. You take a progestogen to stop the lining of the womb building up (caused by taking oestrogen) - which can increase your risk of cancer. The progestogen stops the lining building up, and so lowers the risk of cancer.
Women who have had a hysterectomy do not need to take a progestogen - as the lining of the womb can not built up.
Women who have a mirena coil do not need a progestogen prescription. This is because the mirena coil slowly releases the hormone levonorgestrel - a synthetic form of progesterone. Some women who have a mirena have told us they suffer with less severe menopause symptoms.
Body identical hormone replacement therapy is the gold standard for care. The molecular structure of the body identical HRT is the same as the progesterone in your body. For progesterone the body identical form is ‘micronised’ progesterone (Utrogestan). Micronised progesterone is made from yams.
Body identical progesterone has fewer side effects than other synthetic forms - taking it is simply topping up your own hormones. Body identical progesterone is available on the NHS, and through private providers.
Synthetic progesterones contain molecules which are like progesterone (e.g. MPA, dydrogesterone) or testosterone (e.g. levonorgestrel, drospirenone). Look out for these words long on your medication packet to identify if you're taking a synthetic form of progesterone. These have a slightly higher risk of breast cancer than for body identical forms. 
Yes - most medications can have some side effects. For progestogens side effects may include bloating, spots and mood swings. Women who have Premenstrual dysphoric disorder (PMDD) may be particularly sensitive to changes in progesterone. If advised to try HRT these women should carefully track their symptoms and mood.
We already mentioned that for women with a womb taking a progestogen is important to reduce cancer risk. There are some other risks attached progesterones. They do carry a slight increased risk of breast cancer. If you are taking the body identical form there is no increased risk for the first 5 years of taking it. After 5 years on body identical progestogens there is a small increased risk of getting breast cancer. Importantly this is lower than the risk for a woman taking synthetic progestogen.
The dose you are recommended depends on whether you are taking HRT cyclically or continuously. Learn more about cyclical and continuous HRT in our library.
If you start taking HRT it's important to track your symptoms, and any side effects you might have. It's common that the dose of HRT might need to be adjusted across the first few months.
1 A, Noor et al. (2016). “Progesterone vs. synthetic progestins and the risk of breast cancer: a systematic review and meta-analysis.” Systematic reviews vol. 5,1 121. 26 Jul. 2016, doi:10.1186/s13643-016-0294-5
2 Hillard T., et al. (2017). Management of the menopause. 6th edn. British Menopause Society. UK.
3 Panay, N., Briggs, P., & Kovacs, G. (Eds.). (2015). Managing the Menopause: 21st Century Solutions. Cambridge: Cambridge University Press.