Trisomy 18 Flashcards
What ultrasound findings would lead you to suspect Trisomy 18?
Brachycephaly (strawberry head) Choroid plexus cyst Posterior fossa abnormalities Nuchal translucency verses cystic hygroma Cleft lip/palate Micrognathia CDH Cardiac defect Omphalocele Memnigiomyocele Clenched hands with overlapping index fingers Rocker bottom foot
What percentage of first trimester spontaneous abortion are related to trisomy 18?
18%
What percentage of fetuses with cystic hygroma in the first trimester will be diagnosed with trisomy 18?
18-19%
If fetal trisomy 18 is suspected, how do you counsel the patient on additional testing?
Recommend diagnostic testing with amniocentesis or CVS if earlier gestational age. NIPT if patient declines diagnostic testing.
How accurate us cell free fetal DNA screening in the detection of fetal trisomy 18?
Detection rate is in the mid to high 90s depending on lab.
How do you counsel a patient with confirmed trisomy 18?
About 72% of pregnancies from 12 weeks to term will end in miscarriage or stillbirth.
There is a risk for fetal growth restriction and polyhydramnios which increases with gestational age
If the patient continues the pregnancy with a Trisomy 18 fetus, what complications may develop?
Fetal growth restriction, polyhydramnios, IUFD
Why do fetuses with trisomy 18 develop polyhydramnios
obstructed bowel in the setting of omphalocele, pyloric stenosis or esophageal fistula
If the fetus with trisomy 18 is born alive, what is the likelihood of survival?
10% survive to age 1
