Screening

• Screening embryos


  1. Harvest cells from the developing individual

  2. Amniocentesis (15-16 weeks)

  3. Chorionic villus sampling (10-12 weeks)

  4. Analyse fetal cells in mother's blood
• Amniocentesis


  • Takes fluid from around the developing fetus, which contains fetal cells for genetic screening
• Chorionic villus sampling


  • Takes a small sample of tissue from the developing placenta, which provides fetal cells to screen
• Both amniocentesis and chorionic villus sampling have an associated risk of causing a miscarriage
• Carrying out the screening

  1. Isolate DNA from embryo/fetus cells

  2. Test for specific disorders
• Screening shows fetus is affected


  Parents have a choice to keep the baby or have an abortion/not proceed with implantation
• Pre-implantation embryo screening using IVF can be used to avoid having another affected pregnancy
• Concerns about embryo screening

  • Increased risk of miscarriage from collection procedures
  • Possibility of false positive/negative results
  • Difficult decision to terminate a pregnancy
  • Economic considerations of screening costs and supporting affected children
  • Potential for 'designer babies'
• At the moment, embryo screening can only identify genetic disorders, not cure them
• In future, genetic engineering techniques may be able to repair damaged genes so the child is born unaffected