my son birth weight is 1.9 kg ..he is pre term baby ....but now he is 2 months old and his weight is 3.7 ...¿?is it normal or lower ....than a birth?

A. It is actually better than normal I must tell you why a child who is pretty mature is expected to gain 350 g in a month on the minimum side if you look at that your child has gained about 850 g in a month on top of the birth weight so the weight of the child is excellent and the growth is going very good