clinical consequences of poor placentation - fetal growth restriction Flashcards
objectives
- discuss the causes if a small fetus
- define the concept of fetal growth restrictions (FGR)
- pathophysiology of poor placentation using Doppler assessment
- methods of detecting ….
Define FGR
- conceptual
- condition in which fetus does not reach its biological growth potential
- not all small fetuses are growth restricted (parents small =baby also small genetically)
-not all growth restricted fetuses are small
=> so its hard to define
growth over time (growth vs size
above 90th centile is big
below 10 centile too small
=> growth involves increment in time interval
- usual method is to plot fetal size against gestation
- various centile cut offs are used for diagnosis of SGA
causes of smallness
- dating problems
-constitutional
-primary fetal/environmental problem
-placental insufficiency
smallness : fetal/environment
- edward syndrome > invasive testing putting needle into placenta or uterus to test it
-larger head > triploidy you have an additional set of chromosomes
-dismorphic features > russels silver syndrome which is a genetic cause for growth restriction
Different factors causing smallness
-chromosomal conditions
-congenital infections(rubella, CMV)
-genetic syndromes (eg. Russell-silver)
…..
placental insufficiency
- placental function is nutrient and gas exchaneg
-poor function will lead to : slowing of growth , hyp……
clinical setting - to check for placental insufficiency
- risk factors
-previous history
-positive uterine artery doppler screen
-abnormal placental echo- texture
-AC/EFW below the 3rd centile
doppler screen
high resistence in eye of artery can show risk (doppler screen)
why the eye? bc its a maternal artery , your blood vessels will have high resistance
maternal risk factors
- maternal age > 40
-drug issue
-ongoing smoker - reduces placental function - reduces risk of preeclampsia bc nicotine is a vasodilator
previous pregnancy history
maternal medical history
feto-maternal circualtion
embilical vein - oxygenated blood
baby shunts oxygenated blood via ductus venosus into the heart …..
heart gets oxygenated first
=> system that is prefrentially supplying blood to heart and brain to protect these vital organs
=> ductus venous? and umbilical artery important when looking at…
redistribution
high resistence in umbilical and uterine artery so we look at babys response if baby does not reditribute its fine but if the baby has to do redistribution then you can see this in the doppler screen
-ductus venouses ….?
Doppler flow basics
Defractions are picked up by transducers
-pulse : systolic ejection (peak) and the gaps in between is diastolic
-flow must be forward and if it is reversed it means deoxygenated blood is going back into the baby
during diastole when heart is not pumping blood is still pumping to the placenta
reversed and diastolic - blood goes back - deliver the baby!
-> good end diastolic flow
-> reduced diastolic flow
-> end diastolic flow
-> reversed diastolic flow
