There are two types of abstinence. Both prevent pregnancy. Both keep sperm out of the vagina.
Periodic abstinence is a way that sexually active women prevent pregnancy.
They become familiar with their fertility patterns. Then they abstain from vaginal intercourse on the days they think they could become pregnant. Continuous abstinence is not having sex play with a partner at all. This is the kind of abstinence discussed here. 100 Percent Effective Continuous abstinence is 100 percent effective in preventing pregnancy.