I have to agree with Cetti that the leaflet you found is not Christian.
It doesn't line up with anything I've ever read in the Bible. God has called us to live for Him, to seek to glorify Him in all we do. The Bible does tell us to save our bodies for marriage. A Christian is just a name for a follower of Christ. If you believe Jesus is the son of GOd and that He was sent to save you from your sins, and you desire to know Him and grow in a relationship with Him, then you are a Christian. Jesus was the only human to walk the earth sinless, we can't abstain from sin any more than we can abstain from breathing. But Jesus bridged the gap between God and humans, by paying for our sins on the cross. We can't be perfect, it's impossible, but we can accept God's forgiveness, b/c He freely offers that. And none of that has anything to do with contraception.