In Chinese Culture we normally have a tradition of going into “confinement” for at least 30 to 100 days. During this period, is it OK for friends and relatives to visit me in the hospital and at home? My mother is discouraging me from having any visitors during this time.

There is nothing wrong with receiving visitors right after birth. However, do try to limit the number of people coming to visit you at one time so that you do not expose you and your child to a large number of potential disease transmission and also energy transfers.
This tradition has been passed down through the generations for several reasons.
Firstly, from a practical point of view, by limiting the number of outsiders visiting you, you and your baby are safer from diseases that may be brought by others. Remember, that you are in recovery mode – your body needs alot of rest. New mothers need rest, while juggling the responsibilities of having a new baby to care for!
Another reason why there is a tradition to limit the number of visitors after giving birth, is that sometimes friends and relatives have spirits who follow them. This could be harmful to your child if your child’s internal Spirit Essence or Life Force is not strong. Hence, the traditional custom is to wait for a few months before receiving visits from too many people.
Having said this, visits from close relatives when a child is born, is always regarded as a positive thing. It brings a lot of loving energies as well… so just exercise your discretion. If you are feeling week or if the baby is not well, don’t receive large gathering of visitors.