Chapter 52- Fetal Measurments Flashcards
First trimester measurements
CRL, MSD
2nd/3rd trimester measurements
- Head circumference(HC)
- Bi Parietal Diameter(BPD)
- Femur Length (FL)
- Abdominal Circumference (AC)
The first and most widely accepted means of measuring the fetal head and estimating fetal age in the 2nd trimester
BPD
BPD should be measure in _____ plane
Transverse
BPD is measured at what level
Midline— thalamus, CSP, midline falx
For BPD: calipers should be placed…
Outer edge to inner edge
HC is imaged/measure in ____ plane
Transverse, same level as BPD
Measurement from occipital bone to frontal bone
OFD
Head is SHORTENED in the transverse diameter(BPD) and ELONGATED in the AP diameter(OFD)
Dolichocephaly
Can cause underestimation of fetal age
Dolichocephaly
Head is ELONGATED in the transverse diameter(BPD) and SHORTENED in the AP diameter (OFD)
Brachycephaly
Can cause over estimation of fetal age
Brachycephaly
Cephalic index formula:
CI= (BPD/OFD) x 100
Normal cephalic index
80% + or - 1%
Range of normal cephalic index
75-85 %