Pleasure is not a sin. Neither is pleasure without conscience.

Enjoying the feeling of mud oozing between your toes or the wind stimulating your leg hairs are pleasurable to people and they don't consciously think about it, they just enjoy it.

Lust is the deadly sin you're thinking of. Lust is not the same as pleasure without conscience. Lust is a sin because it leads to disordered love for individuals, is obsessive and can become abusive, and when out of control becomes a distraction from spiritual focus growth. Sin is anything that turns believers away from God.

As you can see, the reasons lust is a sin have nothing to do with pleasure, sex, or unwanted/problematic pregnancies.