Which parameter is most useful for diagnosing fetal growth restriction (FGR)?

Fetal growth restriction (FGR) is a condition characterized by a fetus that is smaller than expected for its gestational age. Among the parameters used in ultrasound assessments to diagnose FGR, the abdominal circumference (AC) is particularly significant because it reflects the growth of the fetus in terms of its nutritional status and liver size, both of which are affected by placental insufficiency, a common cause of FGR.

The AC is measured because it typically provides insight into the fetal growth patterns especially when compared to the expected growth trajectory for the gestational age. When the AC is below the 10th percentile for gestational age, it indicates that the fetus may not be receiving adequate nutrition or has growth abnormalities. This is crucial in diagnosing and managing the potential complications associated with FGR.

While head circumference (HC), biparietal diameter (BPD), and fetal weight estimation also provide valuable information about fetal size and development, AC has been consistently shown to be the most reliable single parameter for assessing fetal growth restriction. The other measurements may not reflect nutritional status as directly as AC does, making it a key parameter in the evaluation of FGR.