What are other Names for this Test? (Equivalent Terms)
- E4 Blood Test
What is the Estetrol Blood Test? (Background Information)
- Estetrol is a hormone produced by a developing fetus during pregnancy. It appears in the mother’s bloodstream, where it may serve as an indicator for the health of the growing, unborn child
- Estetrol is a type of estrogen hormone. It is made from estradiol (E2) and estriol (E3) by the actions of two enzymes, which are 15a-hydroxylase and 16a-hydroxylase. The reactions are carried out in the developing baby’s liver.
- Estetrol crosses the placenta and enters the mother’s blood circulation. Levels of estetrol are detectable after week 20 of pregnancy (in the second trimester)
- During the third trimester of pregnancy, estetrol levels may be used to indicate certain health conditions with respect to the pregnancy. Specifically, if levels of estetrol in the mother’s blood decrease, there may be a problem with the placenta or the fetus
- By the time the baby is born, estetrol makes up 0.05% to 2% of its total estrogen content. Estetrol is no longer made after birth, because the two enzymes responsible for its production stop being made
- The Estetrol Blood Test helps determine the levels of estetrol in the mother’s blood. It is used to help diagnose any associated problems with pregnancy
What are the Clinical Indications for performing the Estetrol Blood Test?
Following are the clinical indications for performing the Estetrol Blood Test:
- Following up to ultrasound imaging indicating problems with fetal development
- Vaginal bleeding
- High blood pressure
- Abnormal weight gain (less than 20 lbs or more than 40 lbs)
How is the Specimen Collected for the Estetrol Blood Test?
Following is the specimen collection process for Estetrol Blood Test:
Sample required: Blood
Process of obtaining blood sample in adults:
- A band is wrapped around the arm, 3-4 inches above the collection site (superficial vein that lies within the elbow pit)
- The site is cleaned with 70% alcohol in an outward spiral, away from the zone of needle insertion
- The needle cap is removed and is held in line with the vein, pulling the skin tight
- With a small and quick thrust, the vein is penetrated using the needle
- The required amount of blood sample is collected by pulling the plunger of the syringe out slowly
- The wrap band is removed, gauze is placed on the collection site, and the needle is removed
- The blood is immediately transferred into the blood container, which has the appropriate preservative/clot activator/anti-coagulant
- The syringe and the needle are disposed into the appropriate “sharp container” for safe and hygienic disposal
Preparation required: No special preparation is needed prior to the test.
What is the Significance of the Estetrol Blood Test Result?
Interpretations of the Estetrol Blood Test value depend on how far the pregnancy progressed.
A low value is indicated as follows:
- Weeks 20-26: less than 140-210 pg/mL
- Week 30: less than 350 pg/mL
- Week 36: less than 900 pg/mL
- Week 40: less than 1050 pg/mL
A low value for the test may indicate:
- Fetal distress
- Intrauterine fetal death
- Anencephalic fetus
- Fetal malformations
The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.
Additional and Relevant Useful Information:
- Currently, there is no one single test that helps determine fetal distress. The Estetrol Blood Test is just one of several tests, including the amniotic fluid index, used for this purpose
Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider of the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.
What are some Useful Resources for Additional Information?
The following DoveMed website link is a useful resource for additional information:
Please visit our Laboratory Procedures Center for more physician-approved health information:
References and Information Sources used for the Article:
Kee, J. L. (2010). Laboratory and diagnostic tests with nursing implications (8th ed.). Upper Saddle River, NJ: Pearson.
Martini, F., Nath, J. L., & Bartholomew, E. F. (2012). Fundamentals of anatomy & physiology (9th ed.). San Francisco: Benjamin Cummings.
Schwers, J. (1965). 15a-hydroxylation: A new pathway of estrogen metabolism in the human fetus and newborn. Biochimica et Biophysica Acta, 100, 313-16.
Williamson, M. A., Snyder, L. M., & Wallach, J. B. (2011). Wallach's interpretation of diagnostic tests (9th ed.). Philadelphia: Wolters Kluwer/Lippincott Williams & Wilkins.