Cigarette smoking just before you get pregnant can increase the risk of an ectopic pregnancy. The more you smoke, the greater the risk. There's no way to prevent an ectopic pregnancy, but here are some ways to decrease your risk: Limiting the number of sexual partners and using a condom during sex helps to prevent sexually transmitted infections and may reduce the risk of pelvic inflammatory disease. Don't smoke. If you do, quit before you try to get pregnant.