Lecture 5B - Fetal Age + Growth Flashcards
2 clinical ways of measuring GA
uterine size/growth
LMP
Exception in which LMP IS accurate (normally is not)
IVF
cons/inaccuracy to measuring GA with uterine size (3)
fibroids
multiple pregnancy
body habitus
small for dates (SFD) (4)
wrong dates
miscarriage
oligohydramnios
inadequate fetal growth (IUFG)
large for dates (LFD) (5)
wrong dates multifetal gestation polyhydraminos fetal macrosomia fibroids
sono measures can be used to determine (3)
fetal age
growth
Estimated fetal weight (EFW)
early sono findings to determine GA (pre 6 weeks)
gest sac = 5 wk
gest sac + YS = 5.5 wk
gest sac + embryo = 6 wk
when is CRL used to determine GA? when is it unreliable
6 weeks
12 weeks
t/f with increasing GA, accuracy of measures decrease
true
4 min measurements for 2nd/3rd trimester
BPD
HC
AC
Femur length
what plane do you measure BPD, HC, OFD?
transverse
what are landmarks for head measurements? (3)
falx cerebri
cavum septum pellucidum (CSP)
thalami
HC formuma
HC = (BPD + OFD) x 1.57
t/f HC is a better predictor than BPD for GA
true
anechoic “box” anterior to thalamus
CSP
in what plane do you measure abdo circumference
transverse
landmarks for AC
liver
umbilical vein
stomach
AC formuma
AC = (AD1 + AD2) x 1.57
what are you measuring with femur length? in which field?
long axis of femoral diaphysis - NOT INCLUDING distal hypo epiphysis
- the nearfield
what is composite dating
using a combination of 2 or more parameters to calc mean GA (if 2 standard deviations, omit from average)
SGA
small gestational age
LGA
large gestational age
what is considered SGA
below 10th percentile
what is considered LGA
above 90th percentile
weight gain reaches a max rate of ______ per week
220 g (1/2 lb)
