<prompt> Chorionic villous sampling done before 10 weeks may result in -Foetal lossFetomatemal haemorrhageOromandibular limb defectsSufficient material not obtained  <response>: 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, 21e, p990NoteDont get confused by what Harrison states on page 399, 15e There is an increased association of limb defects when the procedure in performed later 11 weeks of gestationHarrison is wrong here ! 