15-17 weeks in uterus. foetal cells collected from amniotic fluid surrounding foetus using needle into abdomen. DNA extracted and analysed to detect defective gene mutation
risk of miscarriage (0.5-1%), false positive (abortion of healthy foetus), emotional stress of choosing an abortion
chorionic villus sampling (CVS)?
when foetus is 8-12 weeks in uterus. foetal cells collected from placenta using needle into abdomen/vagina
risk of miscarriage (1-2%), false positive), emotional stress of choosing an abortion
non-invasive prenatal diagnosis?
7-9 weeks in uterus, analyse cell free fetal DNA from mothers blood plasma. DNA extracted and analysed to detect defective gene mutation
false positive, emotional stress of choosing an abortion
testing before implantation?
at 8-cellembryo stage during IVF. 1 cell taken from embryo, DNA extracted and analysed to detect defective gene mutation
false negative, could be used to deal with other characteristics, expensive, stressful, low success rate
