They're having kittens!

[FredPuli43]

"He's having kittens over it", "The goalkeeper's giving his defenders kittens" and so on. When and where did 'giving s.o. kittens' or 'having kittens', meaning creating, or suffering, sudden , but not very serious , anxiety, first come into the language? And why 'kittens' ?

[HowardKennitby]

Cassell's Slang Dict. simply relates this to the general nervousness of a cat about to give birth.

[Quizmonster]

It started life as slang in the USA around 1900, originally meaning 'get angry' before taking on the 'anxious' significance. I wondered whether it was intended to mirror the structure of the rather similar word 'jitters', but that is even newer!