This is very common to have gum problem in pregnancy
due to hormonal changes in the body. But any kind of dental treatment is strictly prohibited in this phase of pregnancy. So you do proper vertical brushing twice a day, massage your gums after brushing twice daily (for upper teeth, massage from upside -down and for lower teeth massage down to upside. And do gargle with warm saline water 2-3 times a day. It will help you.