This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Antenatal Screening, Subject name: Gynaecology & Obstetrics
[{'content': 'Chorionic villous sampling done before 10 weeks may result in - \nSelect and explain. \nA. Foetal loss, B. Fetomatemal haemorrhage, C. Oromandibular limb defects, D. Sufficient material not obtained', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. is \'c\' ie Oromandibular limb defects " Chorionic villous sampling is usually performed at 10-13 weeks and is associated with several complications but studies suggests that limb reduction and oromandibular limb hypogenesis is more common if CVS is done before 9 weeks so CVS is done after 9 wks because it is more safe" - Williams, 21/e, p990NoteDon\'t get confused by what Harrison states on page 399, 15/e" There is an increased association of limb defects when the procedure in performed later (>=11 weeks of gestation)"Harrison is wrong here !', 'role': 'assistant'}]