Yes, an infected tooth can harm your unborn baby. An untreated infection in your mouth can increase the risk of preterm labor and low birth weight babies, as well as cause serious problems for you during pregnancy such as endocarditis (heart inflammation), sepsis (blood poisoning) and meningitis (brain swelling). Additionally, bacteria from the infected tooth may travel to other parts of your body, including the placenta or amniotic fluid around your baby, potentially leading to a miscarriage or even stillbirth. Therefore, it is important that if you experience any pain or discomfort in your teeth while pregnant to see a dentist immediately so they can diagnose and treat any potential issues—for both yours and your unborn baby's safety.