"Might" have been behind it? It was pretty obvious that Norman ordered Mongrain to deliberately put something in MJ's drink to cause her to miscarry (or, depending on how you want to look at it, something which would seem similar to a miscarriage).
Whatever happened to Baby May, there's no denying Norman is responsible. Although it does make sense for the writers not to mention that, because frankly, Peter must be a saint not to have tried to kill the man who killed his girlfriend, "brother" and daughter by now.