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Also known as: Oestrogen forms commonly tested in clinical laboratories are oestrone [E1], oestradiol [oestradiol-17 beta, E2], and oestriol [E3]
Formal name: Oestrogen

At a Glance

Why Get Tested?

To measure or monitor your oestrogen levels if you are a woman who has unexplained abnormal menstrual cycles, abnormal or heavy bleeding, infertility problems, symptoms of menopause, or any other hormonal alterations. It has been used to test for fetal-placental competence during later stages of pregnancy. Oestrogen is also measured in female children suspected of precocious puberty.

When to Get Tested?

When your doctor thinks that you have symptoms of a hormone imbalance, abnormal vaginal bleeding, unusual and/or early sex organ development (male and female).

Sample Required?

A blood sample drawn from a vein in your arm. Occasionally urinary measurements may be required.

The Test Sample

What is being tested?

Oestrogens are a group of hormones primarily responsible for the development of female sex organs and secondary sex characteristics. While oestrogen is one of the major female sex hormones, small amounts are found in males. In women, follicular stimulating hormone (FSH; produced by the pituitary gland) stimulates cells (follicles) surrounding the eggs in the ovaries, causing them to produce oestrogen. When the oestrogen levels reach a certain level, the hypothalamus produces luteinising hormone (LH), which eventually causes the release of the egg, beginning the preparation for fertilisation.

There are three main oestrogen fractions: oestrone (E1), oestradiol (E2) and oestriol (E3). E1 and E2 are the two main oestrogens in non-pregnant females, while E3 is the main pregnancy hormone.

  • Oestrone (E1) is the major oestrogen after the menopause. It is derived from chemicals released from the adrenal gland and is also made in adipose tissue (fat).
  • Oestradiol (E2) is produced in women mainly in the ovary. In men, the testes and adrenal glands are the principal source of oestradiol. Normal levels of oestradiol provide for proper ovulation, conception, and pregnancy, in addition to promoting healthy bone structure and regulating cholesterol levels in females.
  • Oestriol (E3) is the major oestrogen in pregnancy, with relatively large amounts produced in the placenta (from chemicals produced by the baby's adrenal glands and liver). Oestriol levels start to rise in the eighth week of pregnancy and continue to rise until shortly before delivery. Serum oestriol circulating in maternal blood is quickly removed from of the body by the kidneys. Each measurement of oestriol is a snapshot of what is happening with the placenta and fetus but there is also natural daily variation in the oestriol level.

How is the sample collected for testing?

A blood sample will be drawn from a vein in your arm, or rarely you will be asked to provide a urine sample which may involve a 24-hour collection.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

The Test

Common Questions

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.