I still think it sounds like a pro-choice message, personally. If you don't have a choice, that means you aren't pregnant. If you're pregnant, you have a choice.

Could also be a take-off on the "It's not a choice- it's a child" stickers. Which would also point towards pro-choice.

Personally, I can't figure any way of reading it that makes it anti-choice, unless there's some related info I'm just missing.

geminigirl, enlighten us! :)