This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Obstetrics, Subject name: Gynaecology & Obstetrics
IUGR is defined when :- 
Select and explain. 
A. Bih weight is below the tenth percentile of the average of gestational age, B. Bih weight is below 20 percentile of the average of gestational age, C. Bih weight is below the 30 percentile of the average of gestational age, D. Weight of baby is less than 1000 gm
A: Bih weight is below the tenth percentile of the average of gestational age
Answer: A: Bih weight is below the tenth percentile of the average of gestational age 
Explanation: IUGR is defined as, when the Bih weight is below the 10th percentile of the average of gestational age . Classification of IUGR TYPE SYMMETRIC / TYPE 1 (20%) ASYMMETRIC / TYPE 2 (80%) ONSET Early in utero Later onset ETIOLOGY Congenital infections, genetic disorders Utero - placental insufficiency, maternal malnutrition, hypeension,renal disease PATHOPHYSIOLOGY Impaired cell division Decreased cell number Irreversible Impaired cellular hyperophy Decreased cell size Reversible CLINICAL FEATURES Inadequate growth of head and body Head: abdomen ratio may be normal Brain is spared, therefore head: abdomen ratio increased PROGNOSIS Poor prognosis More orable prognosis