What do I need to do if my baby had teeth at birth?

If loose see a DDS. If the teeth are well anchored then they are a normal first tooth, even at birth. Clean it as you would any tooth daily with a cloth or brush. If the tooth is loose see a pediatric dentist, the tooth may need to be pulled.
Ask about removing. A tooth present at birth usually has no real root and may be a choking hazard if it falls out. These teeth are generally removed soon after birth. If the tooth has a good root, it can be left alone. Ask your doctor or dentist whether the tooth needs to be removed.
See your provider. Natal teeth are teeth that are present in an infant's mouth at the time of birth. They're different than regular teeth - often mal- or under-formed. They may be loose, and often doctors consider removing them, especially if they are at risk of falling out (for fear of causing a choking hazard). I'd recommend having a provider check them out for this risk.
Get them removed. This happens sometimes. It will have to be removed so that your baby doesn't choke on it in case it gets loose. Also, you don't want your baby biting you just yet!
See the dentist. If a baby is born with teeth, these teeth usually lack any strong roots. A pediatric dentist can remove the teeth so they won't accidentally fall out and be a choking hazard for the baby. Often there will not be baby teeth in those same spots that had the teeth at birth.