🧪 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).
