The most guaranteed way to prevent an infection of trichomonal vulvovaginitis is to abstain from any sexual activity. If you choose to have sex, there are a few ways to reduce your risk of catching trichomonal vulvovaginitis and other sexually transmitted diseases. The next best way to prevent STD's is to commit to a relationship in which both partners agree to remain exclusive to each other. It is helpful to know if you or your sexual partner has a history of sexually transmitted diseases, and to get tested to see if either of you is currently infected with anything. Condom use greatly reduces, but does not eliminate, your risk of catching or spreading STD's. Other contraceptive methods, such as birth control pills, female condoms, and spermicide, do not protect against sexually transmitted diseases.