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': 'Sonography of a term multigravida shows amniotic fluid index of 3 cm. The fetus may have the following condition: \nSelect and explain. \nA. Oesophageal atresia, B. Spina bifida, C. Cholangioma of placenta, D. Renal agenesis', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Oligohydramnios is defined as an AFI of 5 cm or less, or liquor amnii is deficient in amount to the extent of less than 200 ml at term. Congenital Anomalies Associated with Oligohydramnios: Amnionic band syndrome Cardiac: Fallot tetralogy, septal defects Central nervous system: holoprosencephaly, meningocoele, encephalocoele, microcephaly Chromosomal abnormalities: triploidy, trisomy 18, Turner syndrome Cloacal dysgenesis Cystic hygroma Diaphragmatic hernia Genitourinary: renal agenesis, renal dysplasia, urethral obstruction, bladder exstrophy, Meckel-Gruber syndrome, ureteropelvic junction obstruction, prune-belly syndrome Hypothyroidism Skeletal: sirenomelia, sacral agenesis, absent radius, facial clefting TRAP (twin reverse aerial perfusion) sequence Twin-twin transfusion VACTERL (veebral, anal, cardiac, tracheo-esophageal, renal, limb) association Ref: Cunningham F.G., Leveno K.J., Bloom S.L., Hauth J.C., Rouse D.J., Spong C.Y. (2010). Chapter 21. Disorders of Amnionic Fluid Volume. In F.G. Cunningham, K.J. Leveno, S.L. Bloom, J.C. Hauth, D.J. Rouse, C.Y. Spong (Eds), Williams Obstetrics, 23e.', 'role': 'assistant'}]