Young mother cat-stray

Question
Over the last four months an adorable stray cat, who I estimate to be about 10 months finally became friendly enough to be petted--I have been leaving food and water twice daily.  My dilemma ia this, while I had made arrangements for a vet to examine her, she had apparently become pregnant and I was unable to trap her in time to have her deliver the kittens at the vet's office.  She disappeared for a day (now about 12 days ago), then returned "skinny" for usual feedings.  We have not been able to locate the kittens, even though she lets us follow her to a point, then gives us the slip.  We want to make sure they are all safe and plan to adopt her and at least one kitten, but I can't let her in the house until I locate the kittens.  What should I do--she's the sweetest cat and trys to get in the door when I go to feed her.

Answer
Hi thanks for the question. Can you get a collar with a bell onto her?? She won't like it at first but even though she may act like she is dying.. she is not !!.... then you will be able to follow the sound...
Otherwise as the kittens get older she will be more calm about you seeing them. There are also pet sized GPS units available now but they are very expensive. Teresa