Pregnant Cat Disappeared

Question
From what I've read so far I have a vague understanding that pregnant cats will often wait until they actually begin labor to seek their "birth nest".  My cat, Spooky (approx. 1 y/o), is pregnant and disappeared out the door yesterday morning.  It's been over 24 hours since she's been gone (which is extremely rare).  She gets out quite often, but usually stops by the porch often to "check in" and is visible around the neighborhood, and returns regularly within four or five hours.  Her and our dog, Summer, are always playing around (at first I thought it was aggressive, but seeing as they cuddle on the couch at night I assume it to be innocent roughhousing; neither are food-aggressive or overly territorial).  Honestly I'm not sure how long she's been pregnant, but I wouldn't be surprised if she were due soon.  She's been extremely lethargic the past few days, though eating healthy and still semi-active, but hasn't been trying to get out the door.  When she left the other night, she just up and bolted out after laying in the same spot practically all day, pawing at the dog as she, the dog, passed.  So, to conclude my long-winded -- my apologies -- question, I was wondering if perhaps my cat may have gone into labor and left the house to seek solitude for birth.  If so, will cats usually return "home" with their litter, or at all?  We're very concerned about her and no one has seen her in the neighborhood, which is disconcerting.

Thank you very much for your effort.

Answer
Hi Andrew,

It sounds like she might have had her kittens outside. She may not have felt safe in the house with the dog. She will come back after she has them to eat and drink but will then go back to her nest. You need to watch for her and see where she had them. She will not bring them in. You will need to get them. And the best place to put them is in a cardboard box with sides high enough so she can get out but the kittens can't. Place the box in a closet away from traffic.

Cats will have there kittens in spots where predators can't get them so expect to find them in a area that won't be easy to get them. But you will need to bring them in. There is a lot that can happen to them. Good luck. Write back and let me know if she came back.

Ciao, Karen

Here's some info about nesting boxes from another site.

"The nest box should be large enough for your queen to move and turn around in, and stand up completely, but not so large that it doesn't seem like a private, cave-like, and safe retreat. Cats are known for their love of curling up in small spaces. Cardboard boxes are often used and make great nest boxes. Be sure the front is at least 8-9" high, to keep the kittens in, yet allow your queen to come and go. Do not use any plastic tubs or boxes for your nest boxes, as there have been reports about lost litters due to the chemicals in the plastics. Place several layers of soft clean, absorbent towels inside the nest box, and let your queen dig around and make her nest in them. Once the kittens have been born, it is then fairly easy to peel back and remove the upper, soiled layers of towels with minimal interruption to the mother and her newborn kittens."