What is being tested?

Oestrogen (also known as estrogen) is a group of sex hormones. It’s produced by both females and males, although in much greater amounts in females.

Oestrogen helps the female reproductive organs — the ovaries, fallopian tubes, uterus (womb) and the vagina — to grow and mature. It also helps with breast development.

Oestrogen levels rise naturally during puberty and fall after menopause.

Many females will have a blood test for oestrogen. This might be during pregnancy, or if you are having difficulty getting pregnant. Other times that oestrogen levels are tested are:

• if your menstrual cycles (periods) are not regular
• if you are showing signs of menopause

Your doctor might check 3 types of oestrogen in your blood:

• oestradiol — the main oestrogen hormone important for ovulation (release of eggs) and getting pregnant. Oestradiol supports healthy bones and cholesterol levels in women
• oestriol — important during pregnancy; oestriol levels usually start to rise after week 8 of pregnancy
• oestrone — the most important oestrogen after menopause

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Why would I need this test?

Your doctor might suggest an oestrogen blood test if:

• your menstrual cycle isn’t regular, or you have heavy bleeding
• you can’t get pregnant
• you have symptoms of menopause, like hot flushes
• you have symptoms that might mean your hormones are unbalanced

If you are pregnant, you might have a blood test for oestriol:

• as part of screening for Down syndrome in your unborn child
• to check that your placenta is working properly

Sometimes young people might have an oestrogen blood tests if their sexual development is unusual.

How should I prepare for the test?

What you need to do before your test will depend on the blood test you’re having. Ask your doctor what you need to do before your blood test.

What does the result mean?

Oestrogen levels change during pregnancy, and as you get older. The levels of each type of oestrogen in your blood can change from day to day.

A result outside the normal range might not mean you have a health problem. You might need several tests over weeks or months to check what is happening with your oestrogen levels.

Your doctor is the best person to talk to about your blood test results. You can ask about what they mean and what comes next.

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Resources and support

To learn more about blood tests you can read healthdirect's Guide to blood testing.

Pathology Tests Explained also has lots of information on blood tests including oestrogen tests.

For more information on blood tests during pregnancy check out Pregnancy Birth and Baby.