• Oestradiol, also called E2, is a hormone that is important for fertility and reproductive health in both women and men.
• There are different types of oestrogen and oestradiol is one type.
• It is the main form of oestrogen during a woman's reproductive years.
• Oestradiol levels may need to be measured if someone has unexplained abnormal menstrual cycles, abnormal or heavy bleeding, infertility problems, symptoms of menopause or other hormonal alterations.
• Oestradiol is also measured in girls who may be going through early puberty.
• Men have low levels of oestradiol. The test can sometimes be used to investigate gynaecomastia (male breast swelling) or to look for oestrogen-producing tumours in men.

Oestrogens are a group of sex hormones made by both females and males but made in larger amounts by females.

Oestradiol is the main form of oestrogen and important for the development of female sex organs, including the ovaries, fallopian tubes, uterus (womb) and vagina, as well as breasts. Menstruation, pregnancy and menopause are all influenced by oestradiol.

It is also made by males, although at lower levels, and it affects male fertility such as the ability to achieve an erection and produce sperm.

There are three main types of oestrogen:

• Oestrone (E1) - the major hormone produced by the adrenal gland and in fat tissue after the menopause.
• Oestradiol (E2) - the main oestrogen produced by the ovaries during childbearing years. Normal levels of oestradiol provide for proper ovulation, conception and pregnancy, in addition to promoting healthy bone structure and regulating cholesterol levels in females. In men, the testes and adrenal glands are the principal source of oestradiol.
• Oestriol (E3) - the main form of oestrogen produced by the placenta during pregnancy.

Oestrone (E1) and Oestriol (E3) are rarely tested and then only in specific circumstances. Oestradiol (E2) is usually measured when oestrogen testing is needed because it is the most potent and prevalent form of oestrogen during a woman's reproductive years.

In females, most oestradiol is made in the ovaries, although the adrenal glands (just above the kidneys) and fat cells also make small amounts.

In males, oestradiol is mostly made in the testicles. High amounts are found in sperm.

Ovarian hormones during the menstrual cycle

A complex system involving several hormones are involved in fertility. In females:

• Follicle-stimulating hormone (FSH) made by the pituitary gland (at the base of the brain) stimulates cells (follicles) surrounding the eggs in the ovaries.
• This causes them to produce oestrogen, mainly oestradiol.
• When oestradiol levels reach a certain level, the pituitary triggers the production of luteinising hormone (LH), which eventually causes the release of the egg.

Oestradiol’s effect on other body processes

Oestradiol also plays a role in other important body processes and it can impact on health in many ways. It affects many organs including heart and circulation, muscles, brain function, bone and muscle mass, glucose and cholesterol levels.

You doctor may request an oestradiol level or monitor levels over time for the following reasons:

In women

• Evaluate ovarian function and fertility – this may require repeated measurements over time.
• Monitor hormone therapy (e.g., in menopause or assisted reproduction).
• Diagnose menstrual cycle irregularities or polycystic ovary syndrome (PCOS)
• Monitor ovarian tumours or adrenal disorders.
• Monitoring follicle development in In Vitro Fertilisation (IVF) treatment.

In men

• Investigate symptoms of low testosterone such as gynecomastia or infertility.
• Detect hormone-related conditions such as oestrogen producing tumours.

In children

• Check for early (precocious) or delayed puberty.

Sample

Blood

Any preparation?

None

Reading your test report

Your results will be presented along with those of your other tests on the same form. You will see separate columns or lines for each of these tests.

Interpreting your results

Results of the oestradiol test are usually considered along with those of other hormone tests. Care must be used in the interpretation of oestradiol levels because their levels will vary on a day-to-day basis throughout the menstrual cycle.

If your doctor is monitoring your hormone levels, they will often be looking at trends in your levels, rising or falling over time, rather than at single test results. A diagnosis cannot be made solely based on one test result.

If your results are flagged as high or low this does not necessarily mean that anything is wrong. It depends on your personal situation. Your results need to be interpreted by your doctor.

Possible causes of an increased oestradiol level are:

In women

• Pregnancy – oestradiol levels increase during pregnancy.
• Ovarian cysts or tumours – some ovarian conditions produce excess oestradiol.
• Polycystic Ovary Syndrome (PCOS) – can cause abnormal hormone levels.
• Liver disease – makes it more difficult for the liver to metabolise oestradiol and may lead to higher levels.
• Certain medications – such as hormone therapy, birth control pills or fertility treatments can increase levels.

In men

• Gynecomastia (breast tissue growth) – high oestradiol levels may cause breast enlargement.
• Testicular tumours – some can increase oestradiol production.
• Liver disease – makes it more difficult for the liver to metabolise oestradiol and may lead to higher levels.
• Obesity – increased fat tissue can convert testosterone into oestradiol.

In children

• Precocious or early puberty – increased oestradiol may indicate early onset puberty in girls or boys.

Possible causes of a decreased oestradiol level are:

In women

• Menopause – leads to natural decline in oestradiol levels.
• Primary ovarian insufficiency (POI) – early loss of ovarian function.
• Turner syndrome – genetic condition affecting ovarian development.
• Intensive exercise or extreme weight loss – can suppress ovarian function.
• Pituitary gland disorders – the pituitary regulates oestradiol production and dysfunction can lower levels.

In men

• Hypogonadism – leads to low testosterone production and disturbs the normal balance with oestradiol.
• Pituitary dysfunction – can reduce overall hormone production.

In children

• Delayed puberty – low oestradiol may indicate delayed puberty in girls.

Reference intervals.

Your results will be compared to reference intervals (sometimes called a normal range).

• Reference intervals are the range of results expected in healthy people.
• When compared against them your results may be flagged high or low if they sit outside this range.
• Many reference intervals vary between labs so only those that are standardised or harmonised across most laboratories are given on this website.

If your results are flagged as high or low this does not necessarily mean that anything is wrong. Your doctor needs to take your medical history to help interpret your result.

• Beyond daily and cycle variations, illnesses such as hypertension (high blood pressure), anaemia and impaired liver and kidney function can affect oestradiol levels in the body.
• Increased or decreased levels of oestradiol are also seen in many metabolic conditions.

The choice of tests your doctor makes will be based on your medical history and symptoms. It is important that you tell them everything you think might help.

You play a central role in making sure your test results are accurate. Do everything you can to make sure the information you provide is correct and follow instructions closely.

Talk to your doctor about any medications you are taking. Find out if you need to fast or stop any particular foods or supplements. These may affect your results. Ask:

• Why does this test need to be done?
• Do I need to prepare (such as fast or avoid medications) for the sample collection?
• Will an abnormal result mean I need further tests?
• How could it change the course of my care?
• What will happen next, after the test?

Pathology and diagnostic imaging reports can be added to your My Health Record. You and your healthcare provider can now access your results whenever and wherever needed.

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