It's one of the great many myths out there associated with spaying which are ALL FALSE
CLAIM: Your cat will have a personality change after a spay/neuter.
FACT: It is true that your cat may be a little timid or may just want to curl up and sleep when returning home. That is because they are recovering from surgery, more so if your cat is female. Her operation is equivalent to that of a hysterectomy.
Give her time to recover, about a week. Check that she still eats, drinks, urinates and defecates as normal. Let her come to you. Don't pick her up to give her an affectionate cuddle, she is recovering and not to mention, hurting, thus will lash out at you if you add to the pain. Some vets do provide painkillers if requested. And only use painkillers from the vet as the ones for humans are fatal to cats.
And after recovery, your cat or kitten will be their normal playful self. Keep in mind that their personality is still developing and you still shape it by your actions.
CLAIM: Your cat will gain weight after a spay/neuter.
FACT: As with humans, your cat will gain weight if he/she is fed a rich diet and doesn't excercise. Continue to play with your kitten and once reaching adulthood, change the diet from kitten food to adult food that is a balanced diet.
Encourage your kitten or cat to climb the cat tree or condo. Play games in which they use their hunting abilities and to chase toys.
CLAIM: It's best to allow your kitten, (particularly females), to have a litter of their own first.
FACT: A kitten can reach sexual maturity as early as four months old. And not all female kittens are capable mothers, particularly that young. Not to mention there are millions, possibly billions, of kittens and cats worldwide without homes.
A heat cycle places a lot of stress on the body of the female cat and heat cycles will continue until she is mated or spayed.
Reproduction for a female cat is actually painful. There are barbs on the end of the male penis that cause the female cat pain when he withdraws. This pain is to start ovulation in the female cat.
CLAIM: Males don't need to be neutered.
FACT: An intact male, if an outdoor cat has a significantly larger territory than that of a neutered male. In addition to this, your little boy may be more aggressive towards yourself and other neighbourhood cats.
Wounds from a cat fight can turn into infections that can turn into cysts resulting in large vet bills and constant visits.
In addition to this, an intact male has the ability to impregnate many female cats adding to the situation of where not every kitten has a home. Just because you may not see the litter your male cat has fathered does not mean you are not responsiblle.
They're the ones that I can think of off the top of my head. There are many out there.
Your female kitten will be fine. Let her rest and recover after the operation. Provide a warm sleeping area at ground level, and all the other essentials and before you know it, you woudn't know that she had a spay except for perhaps a tattoo or the certificate.
You're doing a good thing for her.