The hormonal changes of pregnancy can contribute to gum disease. This problem can be prevented or minimized with good oral hygiene that includes brushing and flossing or using another device that gets to the between-the-teeth surfaces every day. For severe or unresponsive situations, professional care would be required to establish health.
Moderate to severe periodontal (gum) disease has also been associated with women that have delivered preterm and low birth weight babies. Researchers are actively investigating the nature of this association. Even if gum disease is not apparent, the best plan is to get good oral care as early in the pregnancy as possible or better yet even before if you are contemplating becoming pregnant. Especially important is to maintain regular preventive oral care at the frequency required to maintain your health during your pregnancy. If dental treatment is needed during your pregnancy the best time to get this done is early in the 2nd trimester.