Fetal Biometry Flashcards
What is the most accurate sonographic method for determining gestational age?
CRL
pg. E 174
If the AC falls below 2 SD, what can it indicate?
IUGR
pg. E 174
If the FL falls below 2 SD, what can it indicate?
skeletal dysplasia
pg. E 174
If the head and/or AC fall short, what should be calculated?
HC/AC ratio
pg. E 174
What does Nagele’s Rule determine?
due date from LMP
pg. E 174
What is Nagele’s Rule equation?
EDC = LMP - 3 months + 7 days
pg. E 174
What is a cephalic index?
defines head shape by dividing BPD by OFD
pg. E 174
What is the normal range for a cephalic index?
- 70 - 0.86
pg. E 174
When is a head considered dolichocephaly?
CI < 0.70
pg. E 174
When is a head considered brachycephaly?
CI > 0.86
pg. E 174
How is OFD measured?
outer to outer (anterior to posterior skull)
pg. E 175
At what level is the AC taken?
stomach
portal sinus of umbilical vein
pg. E 175
What is included in the circumference of the abdomen?
along skin line to include soft tissue and fat
pg. E 175
What is included in the circumference of the head?
not include scalp
pg. E 175
Which measurement is the least reliable in establishing gestational age?
AC
pg. E 174
When is the distal femoral epiphysis visualized?
33 weeks
pg. E 176
What is binocular distance?
measurement from lateral orbital rim to lateral orbital rim
pg. E 176
What is included in a BPP?
fetal breathing gross body movements fetal tone amniotic fluid NST pg. E 177
What is footling breech?
hips extended
feet presenting
pg. E 178
What is frank breech?
hips flexed
knee extended
pg. E 178
What is complete breech?
hips flexed
knees flexed
pg. E 178
A BPD greater than __ cm can indicate macrosomia.
10
What fluid measurement is taken with twins?
maximum vertical pocket
What is included in the NST?
Doppler records fetal heart rate
Stress is added and baby’s heart rate should accelerate
Cerebellum is equal to gestational age up to how many weeks?
28 weeks
When does CRL become invalid for fetal dating?
12 weeks
