They are probably dropping and will have less space to dance around in there.
Many momma cats wont let their kittens nurse until after they are done birthing the whole litter. If the kitten is still not latching on after the other kittens are born you may have to supplement it with a needless syringe and some KMR.The kitten doesn't seem to be latching on to any nipples, is this a cause for concern?