Fetal Imaging Flashcards
if you can only request for one uts throughout pregnancy, do it at ____ weeks
18-20 weeks
clinical use of first trimester uts
fetal age
cardiac activity
fetal number and chorionicity/amnionicity
fetal abnormalities (nt, anencephaly, ventral wall defects)
what do you see when aging fetus
5 weeks: gestational sac
5.5 weeks: gs + yolk sac
6 wks: gs + ys + embryo + cardiac activity
most accurate method to get aog
crown rump length
indications for first trimester uts
- chorionic villus sampling, embryo transfer, localization, removal of iud
- assess for fetal anomalies
- evaluate maternal pelvic masses and/or uterine abnormalities
- measure nuchal translucency for fetal aneuploidy
- evaluate suspected gestational trophoblastic disease
when to measure nuchal translucency
11-14 wks aog
t/f decreased nt in the first trimester may be associated with chd in the second trimester
false, INCREASED NT
trisomy 21 or 18
sign for anencephaly in uts
“frog’s sign”
ventral wall defects
omphalocoele and gastroschisis
t/f if the patient is suffering for pain or bleeding, do not wait for 11-14 wks for an uts
true
three types of uts in second and third tri
standard specialized (congenital anomaly, doppler velocimetry, fetal echocardiography) limited exam (fetal presentation, amniotic fluid, placental localization, fetal gender)
clinical use of uts in 2nd and 3rd trimesters
accurate determination of fetal age fetal number cardiac activity placental localization diagnosis of major anomalies fetal weight estimation
methods for fetal aging in second trimester
biparietal diameter
head circumference
fetal abdominal circumference
femur length
margin of errors in fetal aging via bpd
12-18 wks aog, ~1 wk
2nd t: 2 wks
3rd t: 3 wks
(similar to hc)
purpose of ac
reflects how thin baby is
done when searching for iugr
purpose of fl
most accurate measurement in intrauterine fetal demise
uts can be accurate for fetal imaging until __ weeks
24 weeks with error of 1-2 weeks
t/f the second trimester scan is when fetal presentation is best seen
false, third trimester in order to plan for delivery
how to measure amniotic fluid volume
single deepest pocket: 2-8 cm
amniotic fluid index: 5-24 cm
how to measure fetal weight
biparietal diameter, head circumference, abdominal circumference, femoral length
components of standard fetal anatomical survery
head, face, neck chest and heart abdomen spine and extremities fetal gender
when to do biophysical profile
at term or 28 wks if there are indications
what is tested in biophysical profile
fetal movement fetal tone (flexion/extension) fetal breathing (abdomen) amniotic fluid non-stress test
indications for congenital anomaly scan
- maternal age >35
- previous child with congenital anomaly
- fhx of congenital anomaly
- exposure to radiation or teratogen
- iddm
- repeated pregnancy loss
- severe oligo or polyhydramnios
- iugr
- abnormal placenta
- suspicious findings (enlarged heart)
