B8.021 Prework 2: IUGR

Question 1

what is IUGR

Answer 1

intrauterine growth restriction
failure of the fetus to attain its pre-determined growth potential
baby does not grow at the normal, expected rate

Question 2

clinical definition of IUGR

Answer 2

estimated fetal weight (EFW) < 10th percentile

abdominal circumference < 2.5th percentile

Question 3

3 phases of fetal growth

Answer 3

phase 1 (4-20 wks) = hyperplasia
phase 2 (20-28 wks)= hypertrophy and hyperplasia
phase 3= hypertrophy and tissue growth

Question 4

phase 1 growth pattern

Answer 4

rapid cellular development with mitosis

Question 5

phase 2 growth pattern

Answer 5

increase in cellular size combined with ongoing mitosis

Question 6

phase 3 growth pattern

Answer 6

cells rapidly increasing in size
peak at 33 weeks
rapid accumulation of fat, muscle, and connective tissue

Question 7

when does 95% of fetal weight gain occur

Answer 7

last 20 weeks of gestation

Question 8

symmetric IUGR

Answer 8

20-25% incidence
internal organs reduced in size
reduction in all size parameters
early gestation
genetic disorders and infected fetus
poor prognosis
normal cell size, small cell #

Question 9

asymmetric IUGR

Answer 9

70-80% incidence
head and brain normal in size, abdomen is smaller
third trimester
due to placenta problems
normal cell #, small cell size

Question 10

mixed IUGR

Answer 10

decrease in cell # and size
symmetrical and aymmetrical IUGR
symmetrical IUGR is additionally affected in 3rd trimester due to placental causes

Question 11

physical features of IUGR babies at birth

Answer 11

malnutrition and growth restricted

• small, weight deficit
• head tends to be larger than body
• dry and wrinkled skin (due to decreased subQ fat)
• thin umbilical cord

Question 12

what differentiates IUGR from small babies?

Answer 12

important cause of fetal and neonatal morbidity and mortality
may also develop additional conditions in adulthood

Question 13

causes of IUGR

Answer 13

placental insufficiency (most common)
abnormal chromosomes
abnormalities in a cluster of genes or single gene
silencing of normal genes
syndromes w presumed genetic basis
infections passed to fetus
substance abuse (smoking)
pregnancy at high altitude
starvation
anemia

Question 14

how do you diagnose IUGR

Answer 14

poor maternal weight
development of HTN (due to associated placental insufficiency)
reduced fetal activity
small for date of pregancy

Question 15

normal pregnancy sizes

Answer 15

fundal height progresses at 1cm/week

fundal height that is 3 cm or more behind dates requires US investigations

Question 16

tests done to diagnose IUGR

Answer 16

fundal height
fetal biparietal diameter
abdominal circumference
head circumference
femur length
HC:AC
amniotic fluid index
doppler analysis
ponderal index

Question 17

fundal height

Answer 17

height from top of uterus to pubic bone

Question 18

measurements from US

Answer 18

biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), femur length (FL)

Question 19

amniotic fluid index

Answer 19

estimating the amount of amniotic fluid in gestatoinal sac by US
decreased volume of amniotic fluid (oligohydramnios) is closely associated with IUGR

Question 20

ponderal index

Answer 20

weight-height related parameter

usually normal in symmetric and low in asymmetric

Question 21

considerations for management of IUGR

Answer 21

1. confirm pregnancy dating
2. customization of growth curve (parental characteristics and weights of previous babies)
3. review maternal and pregnancy risk factors
4. investigate non-placental causes
5. placental function testing
6. plan of serial monitoring
7. pediatric consultation for delivery

Question 22

placental functional tests

Answer 22

1. doppler of uteroplacental circulation
2. fetal derived factors in the mother’s blood
3. abnormalities in placental size, shape, texture