UNCONJUGATED ESTRIOL (E3)
Description
- 14th weeks 0.61 – 1.74 ng/ml
- 15th weeks 0.86 – 2.09 ng/ml
- 16th weeks 1.11 – 2.50 ng/ml
- 17th weeks 1.37 – 2.96 ng/ml
- 18th weeks 1.63 – 3.48 ng/ml
- 19th weeks 1.86 – 4.02 ng/ml
- 20th weeks 2.07 – 4.57 ng/ml
- 21st weeks 1.8 – 9.61 ng/ml
- 22nd weeks 2.0 – 10.61 ng/ml
Clinical significance
- Unconjugated Estriol , the biologically active form of estriol, is classified as a weak , short acting estrogen due to its low affinity for the estrogen receptor and its high clearange. It is the weakest of the three major estrogens and is made in large quantities during pregnancy and has potential protective properties against the production of cancerous cells.lt is secreted in small amount by the ovary.
- It is a converted estrogen. It is mainly converted in the liver from estrone and also by a more circuitous route from estradiol.
- During pregnancy, however, the placenta is the major source of estrogen from the hormone DHEA (dehydro epiandrosterone)supplied from either the mother or the adrenal cortex of the foetus. Because of foetal participation in estriol formation, estriol measurements can be a sensitive indicator of placenta and or foetal well being. Normally as the foetus develops estriol production increases resulting in a nearly threefold rise in circulating estriol levels during the final trimester. Persistently low or rapidly falling estriol levels suggest foetal distress.
- Unconjugated or free estriol in serum is used as an aid in monitoring fetal maturity and wellbeing in the context of high risk and poorly dated pregnancies.
- In 2nd trimester Unconjugated Estriol alongwith AFP and HCG (triple marker) forms a powerful tool in evaluation of fetal abnormalities.
- In 3rd trimester: a) Persistently low rapidly falling estriol levels suggest foetal distress b)Serial determination has been used in the management of pregnancies -- complicated by diabetes, hypertension, prolonged gestation, and uncertain dates c) Evaluation of fetal hypothalamic-pituatary adrenal-placental axis d) Evaluation of intrauterine growth retardation e) Very useful in pregnancies with foeto placental dysfunction.
When to get tested
- To Monitor high risk pregnancy
- As a component of second trimester maternal screening
Elevated level
- Increases throughout normal pregnancy
Decreased level
- Trisomy 21( Downs Syndrome)
- Trisomy 18 ( Edwards Syndrome)
- Foetal Distress
- Foetal anencephaly
- Placental sulfatase deficiency
- Foetal death
Profile
Infertility
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