Prenatal Diagnostic Testing Flashcards
What are ultrasounds used for?
Presence of pregnancy and location, multifetal gestation, gestational age, viability, abnormalities
What gestational age can gender be determined?
Around 12 weeks but isn’t always clear
What is a color doppler used for?
To sight the umbilical vein and two arteries
What pregnancy complications would a doppler ultrasound be used for?
Hypertension, fetal growth restriction, placental insufficiency
When is a fetal anatomy scan done?
20 weeks
What is an alpha-fetoprotein screening used for?
To sight open body wall defects/neural tube defects & chromosomal anomalies
When is an AFP screening done?
16-18 weeks
Where is alpha-fetoprotein found?
Maternal serum or amniotic fluid - blood is taken
What is multiple marker screening?
Markers that are added to AFP testing - hCG and unconjugated estriol
What does multiple marker screening increase the chance of finding?
Trisomy 18 or 21…. if positive amniocentesis is recommended
What is chorionic villus sampling and when is it done?
Goes through cervix or abdomen to scrape a sample on villi in placenta. Done at 10-13 weeks
What info does chorionic villus sampling bring us?
Chromosomal defects, metabolic/DNA abnormalities
What is amniocentesis?
Aspirating amniotic fluid from sac
When is the first time an amniocentesis would be done?
15-20 weeks (2nd trimester) to see chromosomal or biochemical abnormalities
When is the second time an amniocentesis might be done?
3rd trimester…. to see fetal lung maturity if baby can survive on own and be delivered OR worried about ABO incompatibility
What is percutaneous umbilical blood sampling used for?
Aspirates fetal blood in umbilical cord near placenta… detects blood disorders, acid-base imbalances, infection, genetic disease
What does a non-stress test (NST) evaluate?
Fetal heart rate accelerations with or without movement. Variation is reassuring (fetus has O2 and neural pathways)
When do we see reactivity in fetal heart rate? How can we stimulate it?
32 weeks - vibroacoustic stimulation
What is a contraction stress test?
Oxytocin given or stimulated to make mom have contractions - sees how fetal heart responds
What are the 5 parameters in a biophysical profile?
Non-stress test Fetal breathing movements Gross fetal movements Fetal tone Amniotic fluid volume (AFI)
How can the mom assess fetal movement?
“Kick counts” - mother can count at least 10 fetal movements within 2 hours or 5-10 movements per hour
When is genetic counseling offered?
Occurrence or risk of occurrence of genetic disease in the family
Who should get genetic counseling? Examples.
Certain racial or ethnic groups, women >35, family history, previous child with disorder, women with past SABs, women with abnormal screenings, etc.
