B8.021 Prework 2: IUGR Flashcards
what is IUGR
intrauterine growth restriction
failure of the fetus to attain its pre-determined growth potential
baby does not grow at the normal, expected rate
clinical definition of IUGR
estimated fetal weight (EFW) < 10th percentile
abdominal circumference < 2.5th percentile
3 phases of fetal growth
phase 1 (4-20 wks) = hyperplasia phase 2 (20-28 wks)= hypertrophy and hyperplasia phase 3= hypertrophy and tissue growth
phase 1 growth pattern
rapid cellular development with mitosis
phase 2 growth pattern
increase in cellular size combined with ongoing mitosis
phase 3 growth pattern
cells rapidly increasing in size
peak at 33 weeks
rapid accumulation of fat, muscle, and connective tissue
when does 95% of fetal weight gain occur
last 20 weeks of gestation
symmetric IUGR
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 #
asymmetric IUGR
70-80% incidence head and brain normal in size, abdomen is smaller third trimester due to placenta problems normal cell #, small cell size
mixed IUGR
decrease in cell # and size
symmetrical and aymmetrical IUGR
symmetrical IUGR is additionally affected in 3rd trimester due to placental causes
physical features of IUGR babies at birth
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
what differentiates IUGR from small babies?
important cause of fetal and neonatal morbidity and mortality
may also develop additional conditions in adulthood
causes of IUGR
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
how do you diagnose IUGR
poor maternal weight
development of HTN (due to associated placental insufficiency)
reduced fetal activity
small for date of pregancy
normal pregnancy sizes
fundal height progresses at 1cm/week
fundal height that is 3 cm or more behind dates requires US investigations
tests done to diagnose IUGR
fundal height fetal biparietal diameter abdominal circumference head circumference femur length HC:AC amniotic fluid index doppler analysis ponderal index
fundal height
height from top of uterus to pubic bone
measurements from US
biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), femur length (FL)
amniotic fluid index
estimating the amount of amniotic fluid in gestatoinal sac by US
decreased volume of amniotic fluid (oligohydramnios) is closely associated with IUGR
ponderal index
weight-height related parameter
usually normal in symmetric and low in asymmetric
considerations for management of IUGR
- confirm pregnancy dating
- customization of growth curve (parental characteristics and weights of previous babies)
- review maternal and pregnancy risk factors
- investigate non-placental causes
- placental function testing
- plan of serial monitoring
- pediatric consultation for delivery
placental functional tests
- doppler of uteroplacental circulation
- fetal derived factors in the mother’s blood
- abnormalities in placental size, shape, texture
