Hello, I am Dr. Judy. I currently live in Arizona, USA. Thank you for using this site, and for trusting me to help you and your pet today.
Ouch! See if you can try to gently extract the back legs with the tail. Make sure your hands are clean. If you can get the back legs (and hips), then wait until mom has a contraction and pushes while you gently pull the kitten out. Don't be surprised if this kitten doesn't make it--sorry, but the cords tend to clamp off if they get stuck in the canal. If this is going to be a problem for you, or you can't get any other part of the kitten out, then you need to rush her to the emergency vet ASAP--make sure you take any kittens already born. I hope this helps and good luck.
We lost the kitten inside the mom Cat! What now?!?!