Untreated gum disease has been associated with premature birth and low birthweight.  Infection of the gums and underlying bone is called periodontal disease and can be safely treated during the second trimester.  Similarly,  tooth removal, and fillings done with anesthetic, can be done during the second trimester.  Swelling and abscesses should be treated immediately, regardless of the trimester.  Women are encouraged to visit the dentist during pregnancy because good oral health is critical to the overall health of mother and child.