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Gastroschisis represents a congenital defect characterised by a defect in the anterior abdominal wall through which the abdominal contents freely protrude. There is no overlying sac or peritoneum, and the size of the defect is usually less than . The abdominal wall defect is located at the junction of the umbilicus and normal skin, and is almost always to the right of the umbilicus.〔Schwartz's principles of surgery: self assessment and board review, 8th edition, chapter 38, page 278; textbook p.1493〕 The defect occurs 5-8 weeks after conception, most likely due to a disruption of the blood supply to the developing abdominal wall.〔http://www.cdph.ca.gov/programs/CBDMP/Documents/MO-CBDMP-Gastromedications.pdf〕 Widespread use of antenatal ultrasound examination and maternal serum alpha-fetoprotein (MSAFP) screening has made the detection of gastroschisis possible in the second trimester of pregnancy. Omphalocele is another congenital birth defect, but it involves the umbilical cord itself, and the organs remain enclosed in visceral peritoneum. With omphalocele the defect is usually much larger than in gastroschisis. == Causes == Gastroschisis is believed to be caused by a disruption of the blood supply to the developing abdominal wall from the omphalomesenteric duct artery by the eighth week of gestation.〔http://aje.oxfordjournals.org/content/155/1/26.full.pdf〕 It is not exactly known what causes this blood supply disruption, but various factors have been shown to increase this risk. Numerous clinical studies have linked aspirin, a U.S. Food and Drug Administration (FDA) pregnancy category D drug, as an increased risk factor,〔http://aje.oxfordjournals.org/content/155/1/26.full.pdf〕〔http://www.ncbi.nlm.nih.gov/pubmed/11772781〕〔http://www.crd.york.ac.uk/crdweb/ShowRecord.asp?LinkFrom=OAI&ID=12009101330〕 and according to large scale study by the California Department of Public Health aspirin quadruples the risk of Gastroschisis.〔http://www.cdph.ca.gov/programs/CBDMP/Documents/MO-CBDMP-Gastromedications.pdf〕 A change in paternity (childbearing with different fathers) has been implicated as a risk factor in a recent study, suggesting that the immune system of the mother may play a role in the development of gastroschisis. It is most commonly seen in young mothers. Newborns are often smaller for gestational age due to their abdomen not expanding because the bowels (and sometimes other organs) are outside of the body. Whether the intrauterine growth retardation can facilitate the apparition of gastroschisis or the abdominal wall defect impairs fetal growth is not clear yet. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Gastroschisis」の詳細全文を読む スポンサード リンク
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