If your pregnant and do not realise it and you keep taking your pill will it cause a miscarriage?

No; at least not with my pill. It says it on the package though, so read the instructions.

Miscarriage / Pregnancy Loss - FAQ (http://miscarriage.about.com/od/riskfactors/f/birthcontrol.htmhere's) an article you might find helpful

can taking birth control cause miscarriage? - Google Search (http://www.google.com/search?sourceid=chrome&ie=UTF-8&q=can+taking+birth+control+cause+miscarriage%3F)
As well as some other sources