Page 54 - SONO 260 The Fetal Head and Brain
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NEURAL TUBE DEFECTS AND THE BRAIN
Alpha-fetoprotein (AFP) is initially produced by the yolk sac, fetal gastrointestinal tract, and the fetal liver, respectively.
AFP exits the fetus through an opening in the neural tube if one is present (i.e., an opening in the cranium or spine), thus allowing for a greater amount to pass into the maternal circulation.
However, increased levels of AFP may not always mean that a neural tube defect is present.
Elevated levels of AFP are also found in the presence of omphalocele, gastroschisis, multiple gestations, fetal demise, and incorrect gestational dating.
