Assessment of Size & Growth Flashcards
How does growth follow a predictable pattern?
influenced by genetic and environmental factors, from conception through neonatal period and beyond
What is the most sensitive biometric parameter for determining GA in the first trimester?
crown-rump length; gauges with a week of accuracy
What is the most sensitive biometric parameter for determining GA in the second and third trimesters?
the fetus is too large to use the crown-rump length measurement, so other features are used
1) OFC- single best predictor
2) abdominal circumference
3) biparietal diameter
4) femur/ humerus length
5) nuchal translucency
6) foot length (least predictive >26 wk)
Why is abdominal circumference a useful diagnostic tool?
functions as a gauge that the baby isn’t growing well- best indicator of IUGR
What are measurements to assess nutrition?
skin fold thickness & mid arm circumference
How should growth be charted daily/weekly?
plot once GA has been determined
1) compare infant to themselves
2) compare to similar infants
3) standard growth charts
What is the expected growth pattern of OFC?
premature infants > 1cm/wk; term 05.cm/wk
How is AGA determined?
weight between the 10th and 90th precentile for GA
How is SGA determined?
< 10th precentile
How is LGA determined?
> 90th percentile
How is LBW defined?
< 2,500g
How is VLBW defined?
< 1,500g
How is ELBW defined?
< 1,000g
What is IUGR?
a neonate who has not grown at the expected rate in utero for wt, length or OFC; not the same as SGA
When does IUGR occur?
typically subsequent to a pathophysiologic process occuring during the perinatal period
What are some clinical features of an IUGR infant?
1) relative lg head compared to body
2) shrunken abd with scaphoid appearance
3) loose skin, sometimes peeling, dry, with appearance of hanging, occasional mec staining
4) long fingernails (especially in term and postterm)
5) face with shrunken appearance; wizened
6) widened or overriding sutures; AF larger than usual
7) thin umbi cord
What is symmetrical IUGR?
proportionate decrease in wt, ht and OFC
What is typical of the etiology of symmetrical IUGR?
usually occurs early in the pregnancy; attributable to single gene defects, chromosomal abnormalities or congenital viral infx
What is asymmetrical IUGR?
decreased in only one biometric parameter (usually weight); usually “brain/head sparing”; a/w better outcomes
What is typical of the etiology of asymmetrical IUGR?
a/w unfavorable intrauterine environment (decreased placental fx or nutritional deficiency)- PIH, poor maternal caloric intake, chronic fetal stress; occurs late in pregnancy, usually 3rd trimester
To whom are LGA infants most frequently born?
DM MOBs with poor glycemic control; maternal hyperglycemia»_space;> fetal hyperglycemia& hyperinsulinemia
Why are IDM infants LGA?
inuslin acts as a growth hormone resulting in macrosomia; IDM baby is more quickly resolved than SGA
Why classify infants?
1) helps establish level of risk for neonatal & long-term morbidity and mortality
2) AGA= at lowest risk for mother and babe
3) if both preterm & SGA= highest risk
4) SGA, LGA & IUGR- at risk for perinatal & long-term problems
How is nutritional status assessed?
1) hair
2) cheeks
3) neck & chin
4) arms
5) back
6) chest
7) abdomen
How can dwarfism be assessed with crown-rump measurement?
should be 2/3 of length
What is the normal range for OFC in a term infant?
33-35.3cm (range 31-38 cm); general rule: HC in cm= 1/2 the length in cm + 10
What is indicated by transillumination of the head with a ring of light > 2cm than the light source?
increased fluid or decreased brain tissue
Why might an infant with a h/o surgically managed NEC present with microcephaly months later?
r/t inflammatory cascade
Why is head growth significant?
correlates with brain growth
How large should the AF be?
size variable from barely palpable to 4-5 cm; larger fontanel may indicate hypothyroidism; closes ~ 18-24mo
How should the AF be measured?
diagonally from bone to bone
What are typical findings of the AF?
1) described as soft and flat
2) tensing or bulging- sign of increased ICP or can occur with crying
3) may appear as bulging in older preterm infants whose skull growth has not kept up with brain growth (lack of Ca and nutrition)
4) sunken- sign of severe dehydration
5) normal to see pulsations
How is the PF located?
run finger along the sagittal suture, may be the size of a dimple
When is the PF closed?
it is usually small, closes by 2-3mo or may be closed at birth
How is chest circumference obtained?
measure horizontally around the upper body at level of nipples; measure during expiration; nipples should not be spaced more than 1/4 of entire chest circumference apart
what is the average chest circumference of a term infant?
33cm +/- 3 cm; about 2cm < OFC
What is the typical nipple width distance of an infant?
27 wks: 4.75cm; term: 7.75 cm
What are the common threats to the IUGR infant’s well being?
- perinatal asphyxia
- PPHN
- RDS
- mec aspiration
- hypothermia
- hypoglycemia
- hyperglycemia
- hypocalcemia
- hyperviscosity
- polycythemia
- decreased immunity
What other anomalies are typically a/w the presentation of a single umbilical artery?
fetal CV, GI and GU
Why does the IUGR infant’s skin appear wizened?
IUGR infants typically have less vernix than their typically developing counterparts, exposing their skin to the harshness of the amniotic fluid
