During puberty, there is increased production of sex hormones. These higher levels increase gum sensitivity and lead to greater irritations from plaque and food particles. The gums can become swollen, turn red, and feel tender. Similar symptoms occasionally appear several days before menstruation. There can be bleeding of the gums, bright red swelling between the teeth and gum, or sores on the inside of the cheek. The symptoms clear up once the period has started. As the amount of sex hormones decrease, so do these problems. Your gums and teeth are also affected during pregnancy.