Any approach to abstinence is only as effective as the individual agreeing to it.

While religious concerns are not everyones, no one has died from abstinence. It's sad to say that the reverse isn't true.

There is a story about children being shown marshmallows and told that if they don't eat it now they'll get a larger reward later.

Most children eat the marshmallow.

The ones who waited were rewarded with giant marshmallows and had more than one.

The experiment was testing willpower and the ability to believe in greater rewards through abstinence. Most children have no concept of getting any good thing from saying no to themselves.

Most of those children grow up to be adults with the same approach to life. Wanting something and getting it without planning, forethought or discipline is rarely a good way to go.

Religion speaks of rewards for waiting. Even if a person has other reasons (such as avoiding unwanted pregnancies, focusing on school first, waiting for Mr/s. Right), there is value in waiting.

The highest rates of teen pregnancy in the entirety of the developed world are in the region of the United States known as the "Bible Belt". For over a decade now the data has proven beyond a shadow of a doubt that purity/abstinence pledges, religion, and abstinence only education are not only ineffective but actively undermine what they are trying to accomplish.

In short: Not only is the answer no, it is Hell No on a scale which I cannot adequately describe with words.