I'm just wondering out of curiousity if its POSSIBLE to be able to find out what exactly caused a miscarriage?

whether its because the mother was smoking, or a virus caused it or because of abnormaIities. I'm asking because a friend said something contrary and I'm just not sure. this question honestly has nothing to do with anything thats going on in my life.(go ahead and say I have an ulterior motive if you want...but...)