Low birth weight is a term used to describe babies who are born weighing less than 2.4kg at birth. It may or may not affect your baby as some babies are constitutionally small because of genetics. If that is not the case, then smallness itself can affect the baby in a few ways - lower sugar levels, more prone to certain types of infection. There could be an underlying condition causing the smallness that may require medical attention. A small baby will need to be monitored by a Paediatrician.