Small for dates pregnancy Flashcards
Define Small for gestational age
birth weight <10th centile
What is intrauterine growth restriction?
fetus that has failed to reach its growth potential due to
pathological restriction
What is the relationship between IUGR and SGA?
All IUGR babies can become SGA
Not all SGA babies are IUGR
What is symmetrical IUGR? What is it caused by? When does it affect the foetus?
proportional growth restriction in all parts of the foetus.
Caused by intrinsic factors e.g. genetic abnormalities + intrauterine infections.
Affects the foetus early in gestation.
What is asymmetrical IUGR? What is it caused by? When does it affect the foetus?
disproportionate growth restriction with a greater decrease in foetal body + limbs compared to head circumference.
Caused by extrinsic factors e.g. placental insufficiency.
O2 + nutrients directed towards vital organs (brain + heart) bypassing other organs (e.g. liver, muscle + fat tissue).
Affects foetus later in gestation.
Give 4 maternal risk factors for IUGR
Age >40y
Previous pregnancy with IUGR
Smoker
Cocaine use
(+Low pre-pregnancy weight/ Under nutrition)
Give 6 maternal medical conditions that are risk factors for IUGR
Pre-eclampsia
AI disease: SLE
Thrombophilias: antiphospholipid syndrome, sickle cell disease
Renal disease
Diabetes
Essential/ gestational HTN
Give 3 uteroplacental risk factors for IUGR
Placental insufficiency caused by maternal/ pregnancy-related conditions
Placenta praevia or placental abruption
Multiple gestation
Give 3 foetal risk factors for IUGR
Congenital/ early IUI: toxoplasmosis, rubella, CMV, varicella, TB, HSV, HIV, syphilis, malaria
Genetic abnormalities: aneuploidy
Congenital anomalies: tracheoesophageal fistula, cyanotic CHD, gastroschisis, or neural tube defects
What are the 4 most common causes of IUGR in practice?
Idiopathic/Unknown
Preeclamspia
APH
Smoking
How does fundal height relate to gestation?
Fundal height in cm should equal weeks gestation
Give 5 circumstances in which fundal height may be inaccurate
High BMI
Fibroids
Multiple gestation
Polyhydramnios + Oligohydramnios
Non longitudinal lie
How should IUGR/ SGA be assessed?
Assess at booking for risk factors
1 major RF: serial USS measurements + umbilical artery doppler at 26-28w
>,3 minor RFs: uterine artery doppler at 20-24w
What USS investigations can be used for IUGR?
Fetal measurements: Abdo circumference + estimated fetal weight
Amniotic fluid assessment
Dopplers
What monitoring is required for IUGR pregnancies?
Umbilical artery Doppler USS every 2w
Monitor foetal movements
What does uterine artery doppler show?
Low or high resistance in uterine arteries at 20-24w
Marker of increased risk
Impedance to flow a/w adverse outcomes eso. pre-eclampsia + IUGR
“Notching”
What does umbilical artery doppler identify?
Fetal compromise in pregnancies complicated by IUGR
What 3 patterns may be seen on umbilical artery doppler?
Present end-diastolic flow (EDF)
Absent end-diastolic flow (AEDF)
Reversed end-diastolic flow (REDF)
Describe umbilical artery absent end diastolic flow
in mid-late pregnancy usually occurs due to placental insufficiency
flow in umbilical artery should be in the FORWARD direction
If placental resistance increases, diastolic flow may reduce, later becoming absent + finally reverses
What is the order of severity of umbilical artery doppler result?
Raised pulsitility index
Absent end diastolic flow (bad)
Reversed end diastolic flow (severe)
What is the management of IUGR?
Conservative: stop smoking
Medical: low dose aspirin if indicated
Surgical: deliver if non reassuring fetal status/ maternal compromise
