In asymmetrical IUGR which organ is not affected –
IUGR is classified as
1) Symmetric IUGR

Reduced growth is an asymmetric → head circumference, length and weight equally affected.
Has earlier onset.
Is associated with diseases that seriously affect fetal cell number, such as conditions with chromosomal, genetic malformation, teratogenic, infectious or severe maternal hypertensive etiologies.

2) Asymmetric IUGR

Reduced growth is asymmetric with relative sparing of head growth.
Has late onset.
Is associated with poor maternal nutrition or with late onset/exacerbation of maternal vascular disease (preeclampsia, chronic hypertension).
Subcutaneous fat
Muscle
Liver
Brain