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Estriol in pregnant women 2

1st trimester:

Less than 38 nanograms per milliliter (ng/mL)

2nd trimester:

38–140 ng/mL

3rd trimester:

31–460 ng/mL


Many conditions can change estrogen levels. Your doctor will discuss any significant abnormal results with you in relation to your symptoms and past health.

High values

High values may be caused by:

Low values

Low values may be caused by:

  • Problems with ovarian function, which can be caused by a failure of an ovary to develop properly (Turner's syndrome) or because of a drop in pituitary gland activity.
  • Anorexia nervosa.
  • Menopause.
  • A problem with the fetus or placenta during pregnancy.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

  • Hormone therapy after menopause.
  • Birth control pills, patches, or rings and other forms of hormonal birth control.
  • Having a test that uses a radioactive substance, such as a bone scan, within 1 week before the test.
  • Medicines, such as clomiphene or steroids (for example, prednisone).
  • High levels of sugar in the urine caused by diabetes.

What To Think About

  • Blood estrogen levels are a more accurate indicator of how well the ovaries are working than urinary estrogen levels.
  • Tests that measure blood levels of progesterone, luteinizing hormone, and follicle-stimulating hormone are often used to study the problems that can affect fertility and the menstrual cycle.
  • In some cases a combination of screening tests is done in the first trimester to look for Down syndrome. The first trimester screening often combines ultrasound measurement of the thickness of the fetus's neck (nuchal translucency) and measurements of hCG and a protein called pregnancy-associated plasma protein A to check for problems. To learn more, see the topic Birth Defects Testing.
  • The level of estriol in the blood is often used in a maternal serum triple or quadruple screening test. To learn more, see the topic Triple or Quad Screening for Birth Defects.

WebMD Medical Reference from Healthwise

Last Updated: March 12, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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