So I like words. I like when we can string words together and make terms we can all understand. I like terms like 'Natural Family Planning.' I like the term 'marital act.' Though both of those get people looking at me funny. Plus there are many people who will always read 'marital' as 'martial' and wonder what the military has to do with making love.
One term that I do not use often is the term 'Birth Control.' Why don't I like the term? Gee, let me count the ways. Wait, let's not and remain charitable instead. Suffice to say I don't support the group who coined the term and it is not a clear or precise term. 'Birth Control' runs the gamut in definition. Contraception is obviously birth control, but then Natural Family Planning is too. Abstinence and abortion are both forms of birth control. Actually even being post-menopausal or pregnant can be termed as forms of birth control. It seems that the only thing not considered birth control by such loose definitions is when a baby is being born. But isn't there an old joke about not asking a woman if she is pregnant unless you actually see a baby coming out of her? I forget which comedian tells it though.
So by formal definition, contraception is a more precise term. If I have to use the other I might use the term 'Birth Regulation' instead. To paraphrase G.K. Chesterton: "With this so-called birth control there is very little birth and almost no control."
Contraception refers to an act done within the context of a sexual act. These acts include using contraceptive devices or practices (e.g. condoms; hormonal pills, rings, injections, or patches; IUDs; oral, rectal, and manual acts that mimic intercourse, yet do not achieve it; and an important note: withdrawl falls in this category.) There is nothing natural about withdrawl and it is in fact the original contraception. To practice contraception one must be engaging in a sexual act. To practice "birth control" one must only need to be breathing.
So if you are used to using those two terms interchangeably, please get un-used to it. 'Contraception' is a precise term while 'Birth Control' is a sloppy one. When a person uses as many words as I do, one tends to get precise before one runs out of air.