Well, a couple of things. Was this intended or accidental? If intended, has she been cardiologist and MRI screened for the two serious health issues in the breed, MVD and syringomyelia, and has the male? If not, I would not go ahead with a litter as it only increases the likelihood of these devastating diseases remaining widespread in the breed.
If accidental, then you have another set of issues to consider. First, she needs to *immediately* see a vet for professional advice on whether she is actually pregnant (and if you go head with the litter, expect this to be the first of many regular and costly visits to xray and monitor then for aftercare...) and to then discuss the options. Foremost will be whether you want to risk your cavalier by putting her through having a litter (there is a fatality risk) and potentially take on very costly emergency care that any pregnant female but especially this small breed, sometimes needs. And also: consider that cavalier mix puppies are no easier to home than any other mix (as you can see by looking at Petfinder or animal shelters nationwide).
If you think the accidental mating was with a dog of larger size, I'd terminate this pregnancy immediately. She could die --painfully -- trying to give birth to puppies from a larger male that she cannot expel (and you could be saddled with thousands of dollars of vet bills trying to save her and/or the puppies). You also need to consider that having a litter generally always carries a risk of death to your cavalier (especially if you have no idea what she mated with, and are unfamiliar with all the complications that can occur during and after pregnancy (very experienced breeders often fail to save a dog or puppies from complications and this breed often has more difficulty than some others).
The issue of making her comfortable is so massive that it really cannot be addressed in a forum (and not here as you will see below
) -- there are literally dozens of considerations, many very serious, and they will change week by week and continue well after any puppies are born. Again, you need expert advice to decide if it is right to have a litter, and that needs to come from a vet and an experienced breeder who can more accurately describe the issues and risks. But as a basic introduction, here's some experienced show breeders explaining what can happen, and what can go wrong:
http://www.angelfire.com/in/kissamikennel/breeding.html
http://www.woodhavenlabs.com/breeding/breeder3.html
http://www.k9web.com/dog-faqs/breeding.html
Also: you need to consider that reputable breeders have a spay clause in their homing contract and if she is pregnant, the breeder needs to be informed while you decide what to do and this may be an ownership issue.
Finally: you are very welcome here to discuss cavaliers, ownership, training, showing, share pictures and so on -- we all love all those aspects of having this lovely breed.
But as you will see if you read the Getting Started section, discussions on breeding cavaliers or whelping litters are not allowed, so I will close this thread (though feel free to start another on a different topic at any time :flwr
.
For all of us: it is so, so critical that females that are not spayed stay inside for the full 4 weeks while they are in heat and are never allowed into a situation where they might become accidentally pregnant. Not only is this a dog welfare issue (millions of unwanted puppies die every year in US pounds -- no breed or mix is immune) but it is also a key responsibility of an owner to keep their dogs safe and healthy. A pregnancy is always a risk, and with the health issues in pedigree breeds, breeding dogs a serious health issue.
