OBGYN Genetic & Aneuploidy Screening Timeline

🧪 OBGYN Genetic & Aneuploidy Screening Timeline

Key prenatal screening and diagnostic test timing by gestational week

10 wks

Cell-free DNA (NIPT)
Chorionic Villus Sampling (diagnostic)

11–13 wks

Combined test:
• Nuchal translucency
• PAPP-A
• Free β-hCG

15–20 wks

Quad screen:
• AFP
• hCG
• Estriol
• Inhibin A

15–20 wks

Amniocentesis (diagnostic)
+ AFP/acetylcholinesterase (NTD)

18–22 wks

Anatomy ultrasound

Buzzword recall:
• 10 wks → NIPT & CVS
• 11–13 wks → NT + PAPP-A + hCG
• 15–20 wks → Quad screen + Amniocentesis
• 18–22 wks → Anatomy scan

✅ Screening = noninvasive (NIPT, serum, US).
✅ Diagnostic = invasive (CVS, amnio).