Q&A: Do I Need To Sterilize?
If baby is healthy and at home (not sick or in the hospital), there's no need to sterilize her bottles or nipples. Washing them in hot, soapy water or a dishwasher before each use will do just fine.
However, if you're pumping for a baby that is in the hospital, most doctors will recommend sterilizing her feeding equipment. Ask your hospital for their specific milk storage guidelines for your baby's special needs.