B8-021 CBCL IUGR Flashcards
[…] signaling in the placenta integrates nutrient availability to regulate fetal growth
mTOR
medical conditions associated with placental insufficiency [3]
preeclampsia
chronic HTN
vascular disease (lupus)
how does disruption of uteroplacental contact cause placental insufficiency?
loss of contact between uterine wall and placenta –> reduced surface area for gas/nutrient exchange –> less fetal growth
how does disruption of typical morphology cause placental insufficiency?
gas/nutrient exchange affected by differing surface area
Examples:
too thick/thin = inefficient or hyperefficient
if cord placement is off, nutrients could take longer to reach fetus
in a normal placenta, how do trophoblasts remodel the spiral arteries for maximal blood delivery?
larger, allowing for high volume low pressure system
(also replace with fibrous tissue to limit vasoconstriction)
describe the deficient spiral artery remodeling occurring in preeclampsia
less depth of invasion
blood arrives with higher pressure, less volume, and pulsatility –> placental stress
histopathologic characteristics of severe/early placental insufficiency
fibrinoid deposits (injury to fetal villi)
syncytial knots (syncytiotrophoblast apoptosis)
the amount in maternal blood reflects the size of the footprint of the placenta on maternal wall
pregnancy associated plasma protein (PAPP-A)
decreased PAPP-A is a risk factor for
IUGR
pregnancy associated plasma protein (PAPP-A) is produced by […] cells
syncytiotrophoblast
AFP is produced by […] cells
fetal liver
used to screen for neural tube defects and abdominal wall defects
AFP
elevated AFP may signal [2]
leaky, damaged placenta
fetal malformations
elevated levels of DIA and hCG is a risk factor for
preeclampsia
IUGR
in animal models where undernutrition is created, the […] pathway creates downregulation of placental transporters prior to the reduction in fetal growth
mTOR
(decreased amino acid transport is a direct contribution to IUGR)
ways to measure placental insufficiency [4]
umbilical artery doppler
proteins in mother’s blood
morphology of placenta
uterine artery doppler
[symmetrical or asymmetrical IUGR]
early in gestation
symmetrical
[symmetrical or asymmetrical IUGR]
late in gestation
asymmetrical
[symmetrical or asymmetrical IUGR]
is more common
asymmetrical
[symmetrical or asymmetrical IUGR]
all measurements at antenatal scan are proportionally reduced
symmetrical
[symmetrical or asymmetrical IUGR]
abdominal circumference decreased
other measurements normal
asymmetrical
[symmetrical or asymmetrical IUGR]
caused by a genetic disorder or infection intrinsic to fetus
symmetrical
[symmetrical or asymmetrical IUGR]
caused by utero-placental insufficiency
asymmetrical
some physical features of IUGR babies at birth
absence of buccal fat
large head
loose, dry skin
thin umbilical cord
poor muscle mass
(basically signs of undernutrition)
short term complications of IUGR that are a consequence of being born preterm [2]
pulmonary hypertension
necrotizing enterocolitis
short term complications of IUGR [3]
hypothermia
polycythemia
renal dysfunction
signs of IUGR during pregnancy [4]
poor maternal weight gain
HTN
reduced fetal activity
abnormal fundal height
fundal height that is […] or more behind dates requires US investigation
3 cm
fundal height of normal pregnancy progresses at […] / week
1 cm
IUGR is commonly known as EFW or AC being less than […]% for gestational age
10
placentas with insufficiency will show obliteration of […]
terminal villi
(reduction of surface area in fetal capillary network)
in placental insufficiency, umbilical doppler will show a reduction in blood flow during
diastole
(can even become absent or reversed in later stages)
a AFI measure below […] cm on US is considered the threshold for oligohydramios
5
[poly/oligo]hydramnios is seen with IUGR
oligo
what are the limitations of using EFW and AC as defining measurements in the diagnosis of IUGR? [3]
intrinsic error of US
does not account for ethnicity/other characteristics that alter the typical curve
does not include doppler findings
about […] of suspected IUGR fetuses are normal constitutional small fetuses
2/3
placental cell-type primarily responsible for nutrient transport
syncytiotrophoblast
clinical definition of IUGR
EFW <10%
phase I of fetal growth is characterized by
hyperplasia
process in pregnancy that is responsible for the transition of high pressure low blood flow to low pressure high blood flow system
spiral artery remodeling
what pathway links nutrient availability to fetal growth?
mTOR
an abnormal uterine artery doppler will show low blood flow from […] to […]
from mother to placenta
clusters of nuclei from apoptotic syncytiotrophoblasts are called
syncytial knots
[…] cells are in direct contact with maternal blood and interface with maternal uterine connective tissue
syncytiotrophoblast
[…] cells lie underneath the syncytiotrophoblasts
cytotrophoblasts
cytotrophoblasts differentiate and fuse into […]
syncytiotrophoblasts
[…] cells form the uterine lining
decidual
cells that form the placental barrier and line the outside of placental villi
syncytiotrophoblasts
[…] can trigger premature placental aging
oxidative stress
(caused by inflammation or hypoxia)
increases the bioavailability of IGF, which regulates placental development
PAPP-A
[…] women have increased rates of babies SGA
short
women who continue to smoke beyond […] weeks gestation have an increased risk for a baby of SGA
15 weeks
fetal microcephaly, intracranial calcifications, and chorioretinitis
congenital toxoplasma
MCA doppler measures bloodflow to the
fetal brain
what would you expect to see on MCA doppler in FGR due to placental insufficiency?
increased diastolic flow
what would you expect to see on umbilical artery doppler in FGR due to placental insufficiency?
decreased diastolic flow
poor pregnancy […] can be non-pathological cause of SGA
dating
what is the cause of hypoglycemia in IUGR infants?
decreased placental transfer of nutrients –> reduced supply
an undernourished fetus will direct most of the blood flow to the […] [2]
heart
brain
genetic aberration occurring in the trophoblast or in progenitor cells leading to abnormal placental development and IUGR
confined placental mosaicism
(only affects placenta; no genetic abnormalities seen in fetus)
