Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
14 Cards in this Set
- Front
- Back
|
Risk factors to consider pre-natal screening
|
- Age
- Diabetes - Any personal/family history of genetic defects (NTD, chromosomal, etc.) - Abnormal ultrasound - Abnormal serum screening |
|
|
Non-invasive screening techniques
|
NOT diagnostic, just indicators
- Maternal serum screening - Triple Screen - Quad screen - 1st trimester screen - Combined screen - ccffDNA testing - Ultrasonography |
|
|
Maternal serum screen
|
Detects MS-AFP (maternal serum alpha-fetoprotein)
- Too high - possible NTD's - Too low - possible triosomies (18 and 21) |
|
|
Triple screen
|
1) AFP
2) hCG (human chorionic gonadotropin) 3) uE3 (unconjugated estradiol) |
|
|
Quad screen
|
1) AFP
2) hCG 3) uE3 4) Inhibin |
|
|
First trimester screen
|
1) hCG
2) PAPP-A (pregnancy-associated plasma protein-A) |
|
|
Combined screen
|
1st trimester screen + NT (Nuchal translucency - thickness)
- Thick NT indicates greater risk of trisomy - Together, these have greater than 90% detection accuracy |
|
|
ccffDNA
|
Circulating cell-free fetal DNA
- found in maternal serum and purified - test for trisomy 13, 18, 21 - Only recommended if positive 1st trimester screen or other family risk factors - Best after 10 weeks |
|
|
Positive indicators of Trisomy 18
|
- low AFP
- low uE3 - low PAPP-A - low hCG - Thick NT *** Inhibin not great test for 18 |
|
|
Positive indicators of Trisomy 21
|
- low AFP
- low uE3 - low PAPP-A - HIGH hCG - Thick NT *** Also high inhibin (if using quad screen) |
|
|
Invasive techniques
|
- Amniocentesis
- Chorionic villus sampling - Percutaneous umbilical blood sampling (cordocentesis) |
|
|
Amniocentesis
|
Take amniotic fluid via syringe
- 15-16 weeks - Isolate, test fetal cells for AFP and other abnormalities - Risk of miscarriage 1/2-300, also infection, cramping, etc. |
|
|
Chorionic villus sampling (CVS)
|
Take some tissue to biopsy
- 11-12 weeks - Risk of miscarriage 1/1-200, others same as amniocentesis |
|
|
NTD
|
Greatly reduced by folic acid intake
- 0.4mg for women with no history, 4mg for those who have - Higher MSAFP for ONTD's! |
