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While spaying is traditionally recommended for kitties between 4 and 6 months of age, spaying as young as 8 weeks old is considered safe, according to Cat Channel. Many animal shelters actually spay kitties prior to adopting them out at this age.
Newborn kittens are tiny and cute, but they grow up startlingly quickly. Many female kittens actually will have their first heats as young as 4 months. To spare your sweet little furball any possibility of pregnancy so young, you can consider spaying as early as 8 weeks old.