Dear friend,
These can be roundworms (most common) hooks, tapes, whips, etc. I am sending you a link so you can see pictures of worms and identify it. Then you can order the appropriate wormer. The vomited up worm is not the issue - it is the eggs that are present in thhe kittens stool. If the pregnant cat comes in contac via the litterbox - she can contract these and pass them to her babies. Keep the boxes separate and do not let the mama cat lick, groom or lie with these kittens.
Hopefully you can treat and eradicate these before the birth. The monthly product revolution will also kill these worms except tapes.
Let me know if you still have questions. I am happy to help inany way possible.
Thank you for being such a wonderful friend to cats. May God bless you.
Very sincerely,
Terri
Dedicated to Cats and the people who love them!
Please press ACCEPT if my answer was helpful and leave feedback Thank you! Terri