This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Paediatric Care in RCH: BW, BL, PEM, Breast Feeding, Subject name: Social & Preventive Medicine
Field instrument used to measure bih weight:- 
Select and explain. 
A. Salter's spring balance, B. Electronic weighing scale, C. Mass produced balance scale, D. Roberval balance
A: Salter's spring balance
Answer: A: Salter's spring balance 
Explanation: - Field instrument to measure bih weight is Salter's Spring balance (kind of sling balance on which child is hung) - Average bih weight = 2.8kg - According to WHO, Low bih weight = < 2.5kg Very Low bih weight = < 1.5 Kg Extremely Low bih weight = < 1 Kg - Bih weight Doubles by 5 months Triples by 12 months Quadruples by 2yrs