Most women show some degree of gingivitis during pregnancy. Pregnancy tends to exaggerate the body's normal response to dental plaque. Hormonal increases create a heightened immunological response to the bacteria in plaque, leading to an increased likelihood for pregnant women to develop gingivitis.  It is important to note, that it is the plaque (bacteria) not the increased levels of hormones that is the major cause of pregnancy gingivitis.

A general swelling of the gums is usually noted in the second month of pregnancy and generally reaches its peak by the middle of the last trimester. The gums can remain swollen for up to 3-6 months after delivery. Pregnancy generally tends to make preexisting gum conditions worse.