Is it ok to have a fellow instead of the main doctor taking care of your baby in the icu?

Academic Hospital ?: If it is an academic or teaching hospital, the "fellow" is probably an advanced post-residency specialist and can provide minute to minute intensive care for your baby.

Be aware of system: Institutions that have "fellows" take doctors that have finished their primary training,including that needed to monitor sick babies & give them added years to focus their activities on the sick babies & do research.Their "main" doctor supervises the program & is available for any questions the fellows may have.This allows the main doc to provide advanced care for more babies.You are lucky.