A week before menstruation, the gums appear swollen and painful situation, may be gingivitis, apical inflammation and other diseases, should pay attention to keep the mouth clean, under the guidance of a professional doctor can use antibiotic treatment or root canal treatment. 1. Gingivitis: when the teeth are infected by bacteria and other pathogens, there may be congestion and swelling, at this time you should actively brush your teeth to keep clean, rinse your mouth with salt water, you can also use antibiotics such as metronidazole for treatment. 2. Root canal inflammation: the deeper layers of the teeth are damaged at this time, which can also cause the gums to become swollen and painful. After adjusting your dental care habits, you need to undergo root canal treatment to remove the necrotic tooth nerves so as to alleviate the pain. Gum swelling and pain before menstruation, and menstruation is not a big relationship, you need to consult a doctor in a timely manner, targeted treatment, to avoid unauthorized use of medication, to prevent the triggering of adverse consequences.