Helpline: 0207 713 7486

Helpline: 0207 713 7486

Timing

Timing of prenatal screening and diagnostic tests offered in the NHS

Early ultrasound scans

  • Fetal viability scan: 6 – 10 weeks
  • Dating scan:  9 – 14 weeks

Screening tests

  • Sickle cell & thalassaemia blood test:  Ideally before 10 weeks
  • Infectious diseases blood test:  8 – 12 weeks

Down’s syndrome, Edwards' syndromne and Patau's syndrome screening

  • Combined test: 11 – 14 weeks + 1 day, (NT scan and two pregnancy hormones are also measured)
  • Quadruple test: 14 weeks +2 days  – 20 weeks + 0 days (four pregnancy hormone levels are measured)
  • NIPT: 10 weeks onwards 

Fetal anomaly scan

  • Detailed ultrasound scan: 18 – 20 weeks + 6 days

Invasive diagnostic tests

  • Chorionic villus sampling (CVS): usually 11 – 14 weeks
  • Amniocentesis: usually between 16 - 22 weeks (but can be done later)

ARC's national helpline

Want to talk? We’re here to talk through your options. Our helpline is answered by trained staff Monday to Friday, 10.00am-5.30pm; call 0207 713 7486.