This subject is clear when it comes to Catholicism who explicitly forbids contraception and encourage natural family planning.
Then most protestants do not forbid the use of contraception.
However when it comes to Eastern Orthodoxy, it seems that there is a smoke in the air, and nobody has a clear position. Orthodox Christians don't have a central catechism like the Catholic Church does, so that only further complicates things.
Does Eastern Orthodoxy have a position at all when it comes to contraception? (My guess would highly be that they forbid it)