Symmetrical intrauterine growth restriction is a type of intrauterine growth restriction (IUGR) where all fetal biometric parameters tend to be less than expected (below the 10th percentile) for the given gestational age. Both length and weight parameters are reduced.
Please, refer to the article on asymmetrical intrauterine growth restriction for a particular discussion of this other type of IUGR.
As a general rule, fetuses with this type of IUGR pattern may present at an earlier stage in gestation compared with the asymmetrical IUGR pattern.
- aneuploidic syndromes
- infections, e.g. TORCH 7
- topical use of maternal fluorinated glucocorticoid (rare) 3
- external agents, e.g. nicotine, alcohol, heroin, ionising radiation 7
All sonographic biometric parameters tend to be symmetrically reduced. Therefore, fetuses have normal or near normal:
- HC (head circumference) : AC (abdominal circumference) ratio
- FL (femoral length) : AC (abdominal circumference) ratio
Differential considerations on ultrasound assessment include:
- incorrect dates
- lower end of normal variation, i.e. if parents are small
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