This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
[{'content': 'Screening by using maternal serum alpha fetoproteins helps to detect all of the following except: \nSelect and explain. \nA. Neural tube defects, B. Duodenal atresia, C. Talipes equinovarus, D. Omphalocele', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Elevated Levels\n\nError in dates\nMultifetal pregnancy\nSevere oligohydramnios\nNeural tube defects\nPilonidal cysts\nEsophageal or intestinal obstruction (and atresia)\nLiver necrosis\nCystic hygroma\nSacrococcygeal teratoma\nFetal death\nAbdominal wall defects:\n\n– omphalocele\n– gastroschisis\n\nUrinary obstruction\nRenal anomalies:\n\n– polycystic kidney\n– absent kidneys\n\nCongenital nephrosis\nOsteogenesis imperfecta\nCongenital skin defects\nCloacal exstrophy\nChorioangioma of placenta\nLow birth weight\nPlacental abruption\nPlacenta accreta\nPreeclampsia\nImproper adjustment for low maternal weight\nMaternal hepatoma or teratoma\n\nLow Levels\n\nG: Gestational trophoblastic diseases\nO2: Overestimated gestational age, overweight mother\nA: Spontaneous abortion\nT: Trisomy (21 or 18)', 'role': 'assistant'}]