The variety of injuries to a fetus caused by material consumption of ethanol is called FETAL ALCOHOL SYMDROME. 
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In catabolism of ethanol by the body, the first step is the conversion to acetaldehyde- the reverse of the last reaction in alcoholic fermentation. The level of acetaldehyde in the blood of a pregnant woman is the detecting Fetal Alcohol Syndrome.
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It has been shown that the acetaldehyde, is transferred across the placenta and that it accumulates in the liver of the foetus, Acetaldehyde is toxic and this is one of the most important factors in Fetal Alcohol Syndrome.
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In addition to the toxic effects of acetaldehyde consumption of ethanol during pregnancy harms the foetus in other ways it depresses transfer of nutrients to the fetus, resulting in low level of sugars (hypoglycemia), vitamins and essential amino acids. Low level of oxygen (hypoxia) also occurs.
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This effects is more drastic when the mother smokes during pregnancy, as well as consume as alcohol. 
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The lebels of alcohol beverages now includes a warning consumption during pregnancy 
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