[31] Small for Gestational Age Flashcards
What is meant by small for gestational age (SGA)?
An infant with a birth weight <10th centile for its gestational age
What is severe SGA?
Birth weight <3rd centile
What is fetal SGA?
An EFW or abdominal circumference <10th centile
What is severe fetal SGA?
EFW or AC <3rd centile
What is fetal growth restriction?
When a pathological process has restricted genetic growth potential
How can fetal growth restriction present?
Fetal compromise, including reduced liquor volume or abnormal Doppler studies
What is low birth weight?
An infant born with birth weight <2500g
What can the pathophysiology of SGA be divided into?
- Constitutionally small
- Placenta mediated growth restriction
- Non-placenta mediated growth restriction
What % of SGA foetuses/infants are constitutionally small?
50-70%
How are constitutionally small foetuses identified?
Small size at all stages, but growth following the centiles
What is the pathology in constitutionally small foetuses?
No pathology is present
What are the contributing factors for constitutionally small foetuses?
- Ethnicity
- Sex
- Parental height
How is placental mediated growth restriction identified?
Growth is normal initially, but slows in utero
What are the maternal factors that can result in placental insufficiency?
- Low pre-pregnancy weight
- Substance abuse
- Autoimmune disease
- Renal disease
- Diabetes
- Chronic hypertension
What can cause non-placenta mediated growth restriction?
- Chromosomal or structural abnormality
- Error in metabolism
- Fetal infection
When should women be assessed for risk factors for SGA?
At booking, and again in 20 weeks
What are the major risk factors for SGA?
- Maternal age >40
- Smoker 11 or more per day
- Previous SGA baby
- Maternal/paternal SGA
- Previous stillbirth
- Cocaine use
- Daily vigorous exercise
- Maternal disease
- Heavy bleeding
- Low PAPP-A
What maternal disease is a risk factor for SGA?
- Chronic hypertension
- Renal impairment
- Diabetes with vascular disease
- Anti-phospholipid syndrome