Is it normal for a cat to only have one kitten?

If a female cat has had several litters yes it is normal for her to have only one kitten and indication the cat is having too many litters. And she needs to be spayed.

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It isn't normal, but it isn't out of the question either, and here is why.

Cats mate differently from most other mammals. When they go into heat, it just means they are ready to get pregnant. They only release an egg when they mate with a male cat, and even that isn't guaranteed. So if you cat only mated once with a male, it is likely to only have one kitten. If your cat mated several times with a male (or several males, which does happen), your cat will likely have multiple kittens. Their ovaries can only release so many eggs per heat cycle, so that is also why if a cat mates, let's say fifteen times in one heat cycle, they won't have fifteen kittens; they will only have four-six, for example. And as the person said above, the more litters a cat has had, the less eggs it will release.