Marathon mum?
From the net, week 27: Around this time, Baby’s eyelids open, so now he is capable of opening and closing his eyes while still inside your uterus! As Baby grows bigger, you may notice some shortness of breath, because your growing uterus presses on your diaphragm and it becomes harder to fill your lungs and breathe out completely.

This is very true. The sleeping part extends to simply sitting down or lying on the couch watching telly: it can be very uncomfortable and tight. But the tougher part is feeling like a big ol' granny, when i try to walk to the store and i arrive completely out of breath, as if i had been running a marathon.

This is when i don't miss my high heels at all.