Both MJ and Peter would be incredibly hesitant about having kids. Purely because of the lifestyle Peter leads. If a pregnancy does happen, I could see it being a unexpected one. MJ wrestling with whether to tell Peter on not. Some great drama could come out of such a situation. But, again, once you head down that road it is a hard one to backtrack on if editorial or writers wish to ditch it later.
Nobody would want another miscarriage situation to occur again. Nor would they welcome a termination.