Tinsel, stronger muscles for labour is not a bad idea. But I wouldn't be too worried about thunder thighs. It is normal during pg to put weight on your thighs and bum - it's your body stockpiling reserves for bfing. If you are like many of us, you will find it will fall off during bfing. If you are unlucky and that is not the case, you can work it off once you are settled with the new baby and certain that the reserves are no longer needed.