It is strongly suggested that pregnant women schedule a prenatal visit with the dentist since hormonal changes related to pregnancy make women particularly prone to gum disease (gingivitis). Women who already have gingivitis will likely find that their gums will become increasingly more inflamed, especially if they do not receive treatment. It should also be pointed out that research shows that changes in estrogen and progesterone levels associated with pregnancy affect the nature of the body’s response to the bacteria responsible for causing periodontal (gum) infections. These infections may pose a threat to the placenta and fetus, increasing the likelihood of preterm delivery. This potential complication alone should prompt pregnant women to schedule regular dental visits. You may not even be aware that you have gum disease because often there is no pain.
P.S. About 40% of women develop gingivitis at some point in their pregnancies.