I thought this was interesting:
You might also feel clumsier than normal, which is perfectly understandable. Not only are you heavier, but the concentration of weight in your pregnant belly causes a shift in your center of gravity. Plus, thanks to hormonal changes, your ligaments are more lax, so your joints are looser, which may also contribute to your balance being a bit off. Also, this relaxation of your ligaments can actually cause your feet to spread permanently, so you may have to invest in some new shoes in a bigger size.