Fetal Alcohol Syndrome: Facial and Developmental Features

Fetal Alcohol Syndrome

FAS requires:
1. Characteristic facial features
2. Growth restriction
3. Neurodevelopmental impairment

Alcohol dose
The uncomfortable truth

There is no proven safe dose in pregnancy.

Why?
• Placenta does not block alcohol
• Fetal blood alcohol ≈ maternal level
• Fetal liver cannot metabolize alcohol
• Individual susceptibility varies

Dose categories

  Exposure pattern   Fetal risk
  Heavy chronic drinking (daily, ≥2–3 drinks/day)   Very high risk of FAS
  Binge drinking (≥4–5 drinks in one sitting)   High risk, even if infrequent
  Low-level regular drinking (1 drink/day)   Increased neurodevelopmental risk
  Occasional small amounts   Risk cannot be excluded

Why dose–response is unpredictable
• Genetic susceptibility
• Maternal metabolism
• Nutrition (folate, choline)
• Timing of exposure
• Placental transport differences

➡ Two women drinking the same amount can have very different fetal outcomes.

Gestational age: timing matters more than total dose
First trimester (3–8 weeks): organogenesis

Highest risk for classic FAS

Alcohol exposure here causes:
• Facial anomalies
• Cardiac defects
• Limb anomalies
• Brain malformations