Also known as: The most common forms of oestrogen measured in the laboratory are oestrone (E1), oestradiol (17-beta oestradiol, E2) and oestriol
Name: Oestrogens
Related tests: Maternal AFP, FSH, hCG , LH, Progesterone, SHBG, Testosterone, Prenatal screening
Why is the test done?
To measure or monitor oestrogen levels in women with irregular periods, heavy or abnormal vaginal bleeding, fertility problems, typical symptoms of the menopause or any other hormone disorder; the test is also used to assess the health of the foetus and placenta in the early stages of pregnancy.
When is it done?
When there are symptoms suggesting a hormone imbalance, abnormal vaginal bleeding, or early and/or abnormal sexual development (in boys and girls).
What samples are required?
A blood sample from a vein. Occasionally a urine sample is requested.
What is being tested?
Oestrogens are a group of hormones responsible for the development of the female sex organs and secondary sexual characteristics. Although oestrogens are the main female sex hormones, low concentrations are also present in men.
In women, follicle-stimulating hormone (FSH, produced by the pituitary gland) stimulates the follicle cells surrounding the egg to produce oestrogens. When the concentration
of oestrogens reaches a certain level, the pituitary gland produces luteinising hormone (LH), which causes the egg to be released, making it available for fertilisation.
There are three main types of oestrogen: oestrone (E1), oestradiol (E2) and oestriol (E3).
• Oestrone (E1) is the main oestrogen present after the menopause. It is derived from precursors produced by the adrenal glands and is also made in fatty tissue.
• Oestradiol (E2) is produced mainly by the ovaries. In men, the main sources of oestradiol are the testicles and adrenal glands. Normal oestradiol levels regulate ovulation, conception and pregnancy, stimulate bone metabolism to promote a healthy skeleton, and regulate cholesterol levels in women.
• Oestriol (E3) is the main oestrogen present during pregnancy: large amounts are made in the placenta from precursors produced by the baby’s adrenal glands and liver. Oestriol levels begin to rise in the eighth week of pregnancy and continue to rise until shortly before delivery. Circulating oestriol is rapidly eliminated by the kidneys. Each oestriol value is therefore a snapshot of the health of the foetus and placenta, although oestriol levels vary from day to day.
How is it used?
When is it requested?
What does the test mean?
Is there anything else I should know?
How is it used?
Oestradiol levels are used to assess ovarian function and to find the cause of precocious puberty (very early signs of puberty) in girls and gynaecomastia in men. Its main role is in finding the cause of amenorrhoea (for example, to assess whether it is due to the menopause, pregnancy or a disease). During treatment for fertility problems, serial measurements are used to monitor the development of follicles in the ovary in the days before in vitro fertilisation. Oestradiol is also measured after the menopause to monitor hormone replacement therapy with transdermal 17-beta oestradiol.
Oestriol, together with alpha-fetoprotein (AFP) and human chorionic gonadotrophin (hCG), is used to assess the risk of the baby having certain conditions, such as Down’s syndrome.
Oestrone can sometimes be useful in diagnosing ovarian cancer, Turner syndrome and hypopituitarism. In men it can be used in the diagnosis of gynaecomastia or in the investigation of oestrogen-secreting tumours.
When is it requested?
Oestradiol may be requested (together with other tests) when there are symptoms such as a feeling of heaviness in the pelvis, abnormal vaginal bleeding or changes in the menstrual cycle, or hot flushes, night sweats, insomnia and/or irregular periods, typical signs of the menopause.
During hormone replacement therapy, oestradiol concentrations may be measured to monitor treatment.
In patients with fertility problems, oestradiol may be measured throughout the menstrual cycle to monitor follicle development before in vitro fertilisation (at the peak of oestradiol levels).
During pregnancy, unconjugated oestriol (i.e. not bound to sex hormone-binding globulin) is measured between the fifteenth and twentieth weeks as part of the triple test.
What does the test mean?
Increased or decreased oestrogen values can be found in many metabolic diseases. Great care must be taken in interpreting oestrone, oestradiol and oestriol values, as these hormones vary during the day and with the menstrual cycle. When monitoring hormone levels, changes over time should be considered rather than individual values. A diagnosis cannot be made on the basis of a single measurement.
Is there anything else I should know?
As well as daily and menstrual variations, conditions such as high blood pressure, anaemia and impaired liver and kidney function can affect oestrogen values.
Increases (corticosteroids, ampicillin, oestrogen-containing products, phenothiazines and tetracyclines) and decreases (clomifene) in oestrogen concentrations have also been reported with some medicines.
1. Do all men have female hormones?
2. What are oestrogen receptors?
3. What are phyto-oestrogens and environmental oestrogens?
1. Do all men have female hormones?
Yes. Although at lower concentrations than in women, they are present and needed for hormone balance and for the function of various glands.
2. What are oestrogen receptors?
Oestrogen receptors are proteins that bind oestrogens and are found on the cells of some tissues. One risk factor for breast cancer is an excess of oestrogens. Exposure to this hormone excess appears to stimulate the growth of cancer cells.
3. What are phyto-oestrogens and environmental oestrogens?
Phyto-oestrogens are oestrogen-like compounds derived from plants. The two main classes are isoflavones, found in soya products, and lignans, found in wheat and some fruits and vegetables. It has been proposed to use these products as an alternative to hormone replacement therapy (HRT). Early studies have shown an improvement in some menopausal symptoms, such as hot flushes, but much research still needs to be done.
Environmental oestrogens are chemicals, both natural (for example of plant origin) and industrial (for example the insecticide DDT), that mimic the effect of oestrogens and can cause fertility problems, thickening of the vaginal lining, early breast development and feminisation in young men. These substances build up in the body over long periods, and their long-term effects are being studied.