What is the normal birth weight?

Question
I am 30 years old and eight months pregnant. I got a sonography done 10 days back, and the report showed my fetus as underweight, only 1.58 kg. The doctor advised me to have a lot of milk, bananas, apples and eggs. He also prescribed Mama Protinex. What is the normal birth weight?
Expert Answer
M
The baby's weight at birth should be more than 2.5 kg.