Spontaneous Heat in a Spayed Cat

Question
I recently adopted a cat from the humane society in my town.  She was five
months old when I got her, and already spayed.  Everything was fine for about
two months, but now she seems to be in heat.  I understand that the spaying
procedure could have been incomplete, but how does that explain her not
going into heat over the past two months?  She isn't very vocal, but is making
strange cooing noises and squatting with her hindquarters in the air and
waddling that way.  Could there be any other explanation for this other than a
botched procedure?  Why would she go for two whole months without going
into heat at a mature enough age to do so, and then spontaneously act this
way?  Thank you for your input!

Answer
Hi Miranda,

On rare occasions there could be some residual ovarian tissue left in a spayed cat. This would account for this behavior. A vet needs to go back into her and remove the ovarian tissue left over. This procedure should be done when your cat is exhibiting the heat signs. You need to take her back and have a vet confirm this. Good luck.

Ciao, Karen