"Again, Miss Granger, I’m not here to interrogate or investigate you over magic. I don’t have to inform you that all magic has consequences. Dark Magic is illegal because it is dangerous. Magic that is particularly dark or ritualistic in nature can have permanent and damaging effects on the body just because of the sheer amount of force and energy that is required. So in this case, by rendering your mind unconscious, your baby was not only protecting its own growth and development, but giving your body a chance to recover. If you perhaps were not magically pregnant, you might have died from casting such intense magic. You could have easily overexerted yourself from performing a simple spell afterwards. Your heart likely would have stopped."