1. Aneuploidy and NTD screening
Karen Marchand, MS, CGC
Lauren Briere, MS, CGC
August 27, 2008
August 27th, 2008
Karen Marchand CGC & Lauren Briere CGC BIDMC OB/GYN RESIDENT DIDACTIC SESSION

2. Overview Markers First trimester screen Quad screen Sequential screen
Interpretation factors
Adverse outcomes
August 27th, 2008
Karen Marchand CGC & Lauren Briere CGC BIDMC OB/GYN RESIDENT DIDACTIC SESSION

3. Nuchal Translucency Measured between 11w2d and 13w6d
Increased: aneuploidy, malformations, parvo, genetic conditions
> 3.0mm- offer CVS, plan for fetal cardiac echo after 20 weeks
August 27th, 2008
Karen Marchand CGC & Lauren Briere CGC BIDMC OB/GYN RESIDENT DIDACTIC SESSION

4. (pregnancy-associated plasma protein A)
PAPP-A
(pregnancy-associated plasma protein A)
Measured in 1st trimester
Produced by placenta
Decreased: trisomies 13, 18, and 21
August 27th, 2008
Karen Marchand CGC & Lauren Briere CGC BIDMC OB/GYN RESIDENT DIDACTIC SESSION

5. (human chorionic gonadotropin)
hCG
(human chorionic gonadotropin)
Measured in 1st and 2nd trimesters (more sensitive in 2nd)
Produced by placenta
Increased: trisomy 21
Decreased: trisomies 13 & 18
August 27th, 2008
Karen Marchand CGC & Lauren Briere CGC BIDMC OB/GYN RESIDENT DIDACTIC SESSION

6. AFP (Alpha fetoprotein) Measured in 2nd trimester
Produced by fetal liver
Increased (>2.50 MoM): NTDs, AWDs . . .
Decreased: Down syndrome
August 27th, 2008
Karen Marchand CGC & Lauren Briere CGC BIDMC OB/GYN RESIDENT DIDACTIC SESSION

7. (unconjugated estriol)
uE3
(unconjugated estriol)
Measured in 2nd trimester
Produced by placenta (precursors from fetal liver & adrenals)
Decreased: trisomies 18 & 21, SLOS, STS
August 27th, 2008
Karen Marchand CGC & Lauren Briere CGC BIDMC OB/GYN RESIDENT DIDACTIC SESSION

8. Inhibin Measured in 2nd trimester Produced by placenta
Increased: trisomy 21
August 27th, 2008
Karen Marchand CGC & Lauren Briere CGC BIDMC OB/GYN RESIDENT DIDACTIC SESSION

9. First Trimester Screening
Free beta hCG & PAPP-A (9w0d 13w6d)
Nuchal translucency (11w2d13w6d)
85% detection rate for Down syndrome
90% detection rate for trisomies 18 & 13
Does not screen for fetal malformations
August 27th, 2008
Karen Marchand CGC & Lauren Briere CGC BIDMC OB/GYN RESIDENT DIDACTIC SESSION

10. Nuchal translucency August 27th, 2008
Karen Marchand CGC & Lauren Briere CGC BIDMC OB/GYN RESIDENT DIDACTIC SESSION

11. August 27th, 2008
Karen Marchand CGC & Lauren Briere CGC BIDMC OB/GYN RESIDENT DIDACTIC SESSION

12. Quad Screen hCG, uE3, AFP, & Inhibin (15-21w)
75-80% detection rate for Down syndrome
65% detection rate for trisomy 18
85-90% detection rate for open defects
Does not screen for trisomy 13
August 27th, 2008
Karen Marchand CGC & Lauren Briere CGC BIDMC OB/GYN RESIDENT DIDACTIC SESSION

13. Sequential screening
First trimester screening PLUS Quad screening (through the SAME lab)
>92% detection rate for Down syndrome & trisomy 18
~90% detection rate for trisomy 13
~85-90% detection rate for open defects
August 27th, 2008
Karen Marchand CGC & Lauren Briere CGC BIDMC OB/GYN RESIDENT DIDACTIC SESSION

14. August 27th, 2008
Karen Marchand CGC & Lauren Briere CGC BIDMC OB/GYN RESIDENT DIDACTIC SESSION

15. Interpretation Factors
Maternal age
Gestational age
# of fetuses (or recent twin demise)
Maternal weight
Maternal race
Vaginal bleeding
FHx NTD
FHx trisomy
Pre-existing IDDM
Maternal AED use
Smoking
August 27th, 2008
Karen Marchand CGC & Lauren Briere CGC BIDMC OB/GYN RESIDENT DIDACTIC SESSION

16. Increased risk? Ultrasound If too early, redraw
If dating off (>1 week) or twins, recalculate
Dating correct:
Aneuploidy – do not re-draw
Open defect – redraw if AFP <3.0 MoM
August 27th, 2008
Karen Marchand CGC & Lauren Briere CGC BIDMC OB/GYN RESIDENT DIDACTIC SESSION

17. (Risk factors are cumulative!)
Adverse Outcomes
Low PAPP- A: IUFD,IUGR, preterm delivery
High hCG: IUFD, pre-eclampsia
High AFP : IUGR, IUFD, preterm delivery, pre-eclampsia, placental abruption
Low uE3: IUGR, IUFD
High Inhibin: IUGR, preterm delivery, pre-eclampsia
(Risk factors are cumulative!)
August 27th, 2008
Karen Marchand CGC & Lauren Briere CGC BIDMC OB/GYN RESIDENT DIDACTIC SESSION