Symmetric intrauterine growth restriction (IUGR) is most often associated with which etiology?

• A. Chromosomal abnormalities
• B. Uteroplacental insufficiency
• C. Severe maternal hypertension
• D. Placental intrauterine infection

Answer: (A)

Symmetric IUGR reflects a growth restriction that affects the fetus globally, indicating an insult that occurs early in development. Chromosomal abnormalities are the classic early insults that disrupt growth of the whole fetus, leading to uniformly small measurements (head, abdomen, and limbs). This early, global disruption makes chromosomal abnormalities the most common etiology associated with symmetric IUGR.

In contrast, uteroplacental insufficiency from maternal hypertension or placental problems tends to cause asymmetric IUGR, where abdominal growth is more affected than head growth due to late-onset placental dysfunction and a brain-sparing effect. Placental infection can contribute to IUGR as well, but the hallmark pattern most strongly linked to symmetry is chromosomal abnormalities.