I`d just give her a little time and see what happens as long as she does`nt seem to be in distress ,other than being in labor.
Is she licking the kitten and otherwise acting motherly?
If so, maybe give her some quiet, alone time, and just keep checking on her.(unless, of course she acts like she wants your company and won`t stay with the kitten she`s already had if you go away)
There may possibly be another (identical twin) attatched to the same placenta, so I would`nt "cut the cord" for her at this point.
I hope all goes well for mama and babies.