How is severe intrauterine growth restriction (IUGR) defined?

Severe intrauterine growth restriction (IUGR) is defined as fetal growth that falls below the 3rd percentile for gestational age. This means that the estimated fetal weight is less than the weight of 97% of fetuses at the same gestational age, indicating a significant deviation from normal growth patterns. When the fetal weight is below this threshold, it suggests serious concerns regarding fetal development, nutrient supply, or overall health.

This classification is important for identifying fetuses at risk for adverse outcomes, such as complications during labor or long-term developmental issues. Careful monitoring and potential intervention, including early delivery or increased surveillance, may be required for fetuses diagnosed with severe IUGR to minimize the risks associated with inadequate intrauterine growth. The other definitions of IUGR, such as less than the 5th percentile or specific weights at term, do not capture the severity as completely as the 3rd percentile does.