Prenatal Diagnosis Flashcards
What is prenatal testing?
It is used to detect abnormalities in a fetus’ genes or chromosomes before birth-offered when there is an increased risk of having a child with a genetic condition due to mother’s age, family history, ethnicity, or US exam.
a needle is inserted transabdominally into the amniotic cavity, and a sample of aniotic fluid is withdrawn
amniocentesis
What is amniocentesis used to look at?
chromosome studies, enzyme measurements, and or DNA analysis
What is an AFP elevation associated with?
an open NTD
Where is AFP produced?
mainly in the liver, secreted into the fetal circulation, and excreted through the kidneys into the amniotic fluid by fetal urine
What are the two approaches for Chorionic Villus sampling?
transcervical and transabdominal
What does a sample from CVS obtain? What is it used for?
fetal trophoblastic cells used for DNA and chromosome analysis
When is CVS performed?
During 10-12 week of pregnancy
When is amniocentesis preformed?
during 15-16 week of pregnancy
the highly vascular outer embryonic membrane that is associated with the allantois in the formation of the placenta
chorion
When is maternal serum screening performed?
during the 1st and 2nd trimesters
When is the maternal serum screen for alpha-fetoprotein for alpha-fetoprotein?
16 weeks
What decreases the incidence of NTDs?
folic acid supplementation starting at least 1 month before conception and continuing through the first trimester reduces by nearly 75%
when does first trimester screening take place?
weeks 11 and 13
When does second trimester screening take place?
weeks 15 and 20
