I came across a piece from about a year ago, talking about celebrity shoe choices and foot problems. How can these ladies grin and bear it when their feet are screaming!?! As I've said in the past, your choice of shoes greatly influences your function later on. Some shoes can be worn in moderation, but others are just plain not worth the risk, even for just a night.
If you are pregnant, take care of your feet and give them the room and support they need. If there is an event that you need to dress up for - at least make sure your shoes fit. Instability in high heeled shoes is a given - when this is coupled with inappropriate fit, your risk of sprain or fracture is even higher.
Learn what NOT to wear for shoes here...these pictures make my feet hurt!