Hi, I think that is rather unfair, as long as you have no major health problmes affecting your ability to trian and sudequently practice as a midwife, I fail to see what difference your size makes!
There are plenty of large midwives who have no problem (well, they have the same problem with scrubs, but that is all)
Honestly?
if you are well, and well done for losing 4 stone btw, that must've been hard, then go for it!