Ch. 3 Prenatal Genetics Flashcards
What is Roberstonian translocation?
structural rearrangement involving one or mroe acrocentric chromosomes (13, 14, 15, 21, 22)
What is considered advanced maternal age?
woman is 35 years or older at time of delivery
What are the 3 major categories of prenatal genetic screening?
ultrasound | maternal serum screening | noninvasive prenatal screening (NIPS)
What are soft markers?
subtle changes that alter a woman’s risk for specific types of aneuploidy
At what fetal age does nuchal translucency measurement via ultrasound need to be done?
11wks 1 day to 13wks 6 days
What are some possible indications of a thick nuchal translucency? What is the next step if thick NT is shown?
structural anomaly, cardiac defect, pending fetal demise | fetal echocardiogram during 2nd trimester
What are the 7 things an ultrasound evaluates for?
fetal number and presentation | amniotic fluid volume | fetal biometry | cardiac activity | placental position | anatomic survey | due date
What is the earliest gestation time an ultrasound is done?
18-22wks
What is the gestation period for high miscarriage zone (spontaneous abortion)?
8-10 wks
What is non-invasive prenatal screening entail?
cell free DNA screening = evaluates fragment DNA in mother’s blood from placenta | highest detection rate and lowest false positive rate
What does non-invasive prenatal screening detect?
DNA fragments associated with aneuploidy conditions
What gestation age can NIPS be done?
10 wks
What is nuchal translucency?
how much can you see through the region to see the fetus
What is maternal serum screening and what is it used for?
analysis of analytes found in pregnant woman’s blood to assess risk of aneuploidy and ONTDs
What is open neural tube defects?
problems with how the brain, spinal cord/spine forms during gestation