1: Neonatology - IUGR Flashcards
Define IUGR
Failure of growth in-utero that may or may-not cause SGA
Define SGA
Weight below 10th-centile for gestational age
What are the two types of IUGR
1, Symmetrical
2. Asymmetrical
What causes asymmetrical IUGR
- Due to external factors, most commonly placental insufficiency. Occurs late in gestation.
What causes symmetrical IUGR
- Due to internal factors (Chromosomal abnormalities)
What are two maternal causes of IUGR
- Substance abuse
- Teratogenic medications
What is the main utter-placental cause of IUGR
Placental insufficiency
What is placental insufficiency
Disruption in maternal-foetal circulation impairing substances exchange causing foetal compromise
What are 5 causes of placental insufficiency
- DM
- HTN
- Smoking
- Antiphospholipid syndrome
- SLE
- Pre-eclampsia
- Rhesus incompatibility
What are 3 foetal causes of IUGR
Chromosomal abnormality
TORCH
Cyanotic heat defects
What is 70% of IUGR
Asymmetrical
How will symmetrical growth IUGR present
Proportional decrease in head and abdominal circumference
When does symmetrical IUGR usually occur
Abnormalities in brain development
What is a more common complication of symmetrical IUGR and why
Abnormalities in brain development - due to occurring in first trimester
How does asymmetrical IUGR present
Maintained head circumference, small abdominal circumference
Explain pathophysiology of asymmetrical IUGR
Placental dysfunction decreases nutrients and oxygen delivered. Foetus therefore preferentially shunts oxygen and nutrients to vital organs, including the brain. Foetus then switches to glycolysis, which causes metabolic acidosis and foetal multi-organ failure
What are features of IUGR on growth restriction
Below 10th gentile
May have oligohydramnios
In asymmetrical IUGR, what will be seen on doppler US
Reduced umbilical blood flow
What is a risk with IUGR
Baby born low birth weight - which increases risk of sudden infant death syndrome
What is small for gestational-age
Weight below 10th centile of that for gestational age
What is symmetrical SGA
All growth parameters are symmetrically small
What causes symmetrical SGA
Chromosomal aberrations
Constitutionally small
What is asymmetrical SGA
Weight is proportional smaller compared to head circumference and length
What is the main cause of asymmetrical SGA
Pre-eclampsia
What does SGA increase risk of
Perinatal asphyxia Hypoglycaemia Necrotising enterocolitis Meconium aspiration Polycythaemia TORCH infections
Why does SGA increase risk of hypoglycaemia
Less glycogen stores
Why does SGA increase risk of polycythaemia
Chronic in-utero hypoxia
What is LGA
Babies weight >90th centile that for gestational age
What are 4 causes of LGA
Constitutional
Maternal DM
Beckwith-weidemann syndrome
Hydrops foetalis
What is the presentation of beckwith-widemann syndrome
Hypoglycaemia
Crease near ears
Organomegaly
Macroglossia
What are the risks of LGA
Syndrome of over-growth that presents with
- Perinatal asphyxia
- Shoulder dystocia
- Clavicle fracture
- Nerve palsies
- Hypoglycaemia
