4 things you should know for a clean, healthy smile - Parenting.com
Q. Is it safe for me to use a tooth whitener while I'm pregnant?
A. No. You won't find pregnancy-related warnings on most over-the-counter whiteners, but dentists suggest avoiding them until after you give birth (and finish nursing, too).
Your gums are more sensitive when you're expecting, so using a tooth whitener might increase irritation -- although no studies have actually been done, according to Kimberly Harms, a dentist in Farmington, MN, and a spokesperson for the American Dental Association. And if you swallow some, it isn't clear how the product's ingredients can affect your baby-to-be, another reason to steer clear.