Well - I've heard a story about 19 years old Maine Coon queen (in US) been chased off the tree to give a birth inside! But Maines are big!
That was from very experienced breeder.
I've just spayed one of my girls (5 years old) : she had a litter a year, but always 6 or 7 babies - which is a lot; she was a good mom and granny and now going to enjoy her retirement.

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