Recommend 35 years by time delivery
High risk, family history
Triple screen 70% sensitivity
- AFP dec 0.7
- HCG inc 2.0
- Estriol dec 0.7
Quad Screen 80%
- Add inhibin inc 1.77 (not used in trisomy 18)
Nuchal translucency 1st trimester 11-13 weeks 70% alone
- Fluid collection back neck fetus
NT+B HCG & PAPP-A (glycoprotein like HCG produced by trophoblasts dec 0.43)
1st trimester 85%
Combined HCG/PAPP-A & AFP/Estriol/inhibin
Integrated Screen 94-96% (NT +HCG, PAPP-A & QUAD)
Serum Integrated 85& (PAPP-A & QUAD)
NT- useful multigestation since serum screening not accurate in twins. Not available with triplets or high order multiples
- 12-13 weeks 70% trisonomy 13, 18, 21
- 87% Turner’s syndrome
- 59% triploidy
Positive 1st trimester screen
- Genetic counseling
- Invasive testing
U/S 2nd trimester
- Soft markers pyelectasis, shortened femur or humerus, echogenic bowel, and intracardiac echogenic focus individually do not significantly increase risk Down’s syndrome
Question-
Highest detection rate for Down’s syndrome
- Thickened muchal fold
- Cardiac defects
Nasal bone and tricuspid regurgitation clinical useful uncertain still research
Increased AFP > 2.0-2.5
- NTD’s anencephaly, spine bifida, gastrichasis, omphecele
Increased acetylcholine 100% with anencephaly and open spine bifida