how old does a female cat have to be to come in heat?

Kittens can & quite commonly DO go into heat for the first time as wearly as 6 months...usually it tends to be a bit alter but if you REALLY dont need kittens you need to get her spayed ASAP! Especially as you say she is indoor/outdoor if there are males in the area it can trigger her to go into heat earlier. With animals its all about survival & continuing the line so nature takes its course & does what needs to be done to make those things happen....make a vet apt ASAP & for precautionary reasons Id keep her inside untill shes spayed. Best of luck.

My 2 kittens are 9 months they started acting strangely at 6 mo. They are indoor though we have a male cat also.. but neutered (sp?).. p.s. when they are in heat they like to be outside because they wont stop goin in heat until they have mated or are spayed..

spay her...

Get her indoors and stop letting her run free - cats are NOT wild animals like squirrels or raccoons and should not be allowed to run loose. And get her to the vet NOW, tomorrow if possible - she is plenty old enough to be spayed. If she's pregnant now, the vet can remove the fetuses if they're not too big. Just get it DONE and then quit letting her run loose.

My cat wasn't even one year old when she had kittens, so pretty young.

I have good news and bad news.

The good news is your cat is old enough to be spayed by a veterinarian so that she will not have kittens.

The bad news is that if you don't do this soon you will have kittens.

Hope this helped :)

HE HAS EVERY RIGHT TO BE WORRIED, GET HER INDOORS ASAP, UNTIL YOU GET HER TO THE VET TO GET HER FIXED..THEY TOLD ME THEY CAN START AT 5 MONTHS SOMETIMES 4...ALSO, WHY DO YOU PEOPLE LET YOUR CATS OUT???? I STILL CAN'T UNDERSTAND THIS..IS IT BECAUSE YOU DON'T WANT TO BUY LITTER, OR YOU LIKE HIGH VET BILLS???