Pregnancy hormones may cause your gums to swell, become inflamed, and bleed more easily. During pregnancy, your mouth may also become more vulnerable to bacteria and plaque, and this can make your gums more tender gums. For this reason, it is very important to maintain good oral hygiene when pregnant and to visit the dentist for regular cleaning appointments. To help prevent tooth decay and gum disease, always brush your teeth twice a day and floss your teeth once a day, eat a balanced diet and limit between-meal snacks.