30.下列何種情形不會造成懷孕時母親雌激素（estrogen）濃度降低？
(A)胎兒死亡（fetal demise）
(B)胎兒胎盤硫酸酯酶缺乏（fetal-placental sulfatase deficiency）
(C)唐氏症（Down syndrome）
(D)胎兒骨髓成紅血細胞增多症（fetal erythroblastosis）

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統計： A(18), B(22), C(251), D(277), E(0) #3260694

詳解 (共 2 筆)

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Fetal Conditions aff...
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#6423895

Role of DHEA in the Feto-Placental Unit

image2052.jpg
1. Production of DHEA-S by the Fetal Adrenal Glands
The fetal adrenal cortex, particularly the inner fetal zone, produces large amounts of DHEA sulfate (DHEA-S) under the stimulation of ACTH. By mid-gestation, the fetal adrenal glands can produce approximately 100–200 mg/day of DHEA-S .


2. Conversion in the Fetal Liver
DHEA-S is transported to the fetal liver, where it undergoes hydroxylation to form 16α-hydroxy-DHEA-S (16α-OH-DHEA-S). This metabolite is a key intermediate in the biosynthesis of estriol (E3), the predominant estrogen during pregnancy .

3. Transformation in the Placenta
The placenta takes up 16α-OH-DHEA-S and, through the action of steroid sulfatase and aromatase enzymes, converts it into estriol. This process involves several steps, including desulfation, conversion to 16α-hydroxyandrostenedione, and aromatization to 16α-hydroxyestrone, which is then transformed into estriol.
沒有sulfatase這部沒辦法達成

4. Secretion into Maternal Circulation
The estriol produced is predominantly secreted into the maternal circulation. Approximately 90% of estriol precursors originate from the fetus, highlighting the interdependence of the fetal and placental units in estrogen production during pregnancy.
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這也是為什麼二唐的檢查項目 （AFP uE3 bhCG DIA)裡面有uE3，量大概是正常預測值的75%
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私人筆記 (共 1 筆)

私人筆記#7616522
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唐氏症 → 雌三醇（estriol）...
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