I would interested to know how she is putting her baby and herself at risk sitting in the exit. Pregnant women are just pregenant, not useless. If she is happy opening the exit and throwing it out then I fail so see why it is an issue.

Surely it's far safer to be in an exit row than not, provided you are not in the A or F seat and the door falls on your head.

There are going to be plenty of people to give a hand if needed, and this applies equally to "able" people who are clueless at opening the door or don't realise how heavy it is and drop it etc.