Prenatal (1) Flashcards
What is the background risk for neural tube defects?
1/1000
What are the 3 most common neural tube defects?
spina bifida
anencephaly
encephalocele
How much folate should women take to reduce risk of neural tube defects?
400 micrograms daily
Name 2 heart defects detected on ultrasound that are associated with T21
AVSD
VSD
Name 1 heart defect detected on ultrasound that is associated with Turner syndrome
coarctation of the aorta
Name 1 heart defect detected on ultrasound that is associated with 22q11.2 deletion
tetralogy of Fallot
What percentage of fetuses with T21 have an absent / short nasal bone on ultrasound?
60%
What are the main things to think about with an absent / short nasal bone? (5)
often normal variation T21 T18 T13 Turner syndrome
What is the incidence of nonsyndromic cleft lip and/or palate? What ethnic groups have a higher incidence?
1/1000 live births
more common in Native Americans and Asians
What is the percentage break down of isolated vs. syndrome cleft lip and/or palate?
60% isolated
40% syndromic
What are the most common syndromes associated with cleft lip and/or palate? (5)
more common: T18, T13
other: T21, 4p-, 22q11.2 deletion
What is the incidence of clubfoot?
1/1000 live births
What can cause clubfoot? (4)
- multifactorial inheritance
- intrauterine environment
- T18
- smoking (20-fold increase in risk)
What is the recurrence risk of clubfoot if a parent was affected?
20%
What is the recurrence risk of clubfoot if a non-parent first-degree relative was affected?
4%
What is the incidence of increased NT / cystic hygroma?
1/500 pregnancies
What conditions are most commonly associated with increased NT / cystic hygroma? (7)
T21 Turner Noonan 22q11.2 T18 T13 cardiac defects
What factors other than genetic conditions can be associated with increased NT / cystic hygroma? (2)
virus
alcohol
If increased NT / cystic hygroma is seen in the first trimester, what is it more likely to be due to?
In the second trimester?
1st: autosomal aneuploidy
2nd: Turner
What is the incidence of choroid plexus cyst (CPC)?
1/100 normal fetuses
What is the natural progression of a choroid plexus cyst (CPC)?
usually resolves by 26 weeks without problems
What conditions is choroid plexus cyst (CPC) most commonly associated with? (2)
T18
other chromosome abnormalities
What is the incidence of echogenic bowel?
1/100 - 1/200 fetuses
What is the natural progression of echogenic bowel?
usually not associated with anything major and resolves without problems
What genetic conditions can echogenic bowel be associated with? (2)
T21
CF
Other than genetic conditions, what can echogenic bowel be associated with? (4)
viral infection
GI malformations
IUGR
intra-amniotic bleeding
Name 6 genetic syndromes associated with NTDs:
- Meckel-Gruber
- Roberts
- Jarcho-Levin
- HARD
- T13
- T18
What percentage of twins are monochorionic vs. dichorionic?
30% mono
70% di
What U/S finding has a very high association with spina bifida?
lemon sign
What recommendation should you make to a woman who has had a previous pregnancy with a NTD?
10x the dosage of folic acid
What do gravida and para stand for?
gravida = number of pregnancies para = number of pregnancies carried to full term
What percentage of T21 is detected on ultrasound?
50%
What percentage of T18 is detected on ultrasound?
75%
What percentage of T13 is detected on ultrasound?
75%
What percentage of spina bifida is detected on ultrasound?
80%
What percentage of anencephaly is detected on ultrasound?
100%
Name 5 US findings indicative of T21:
- increased NT
- heart defect
- echogenic bowel
- short leg bones
- ventriculomegaly