Has your wife been to the hospital since the miscarriage? The Vale's Lily is right about what the hospital does with a fetus..... but regardless of if you take the fetus in or not, your wife should still be seen so they can make sure that everything has come out properly and there were no complications. I had a miscarriage at 12 weeks, so I can empathize with your wife. Sorry, I can't tell you anything about Islamically how to handle the situation. I wish you and your wife all the best.