Female cats should be spayed before they are 6 months old to prevent urine spraying and to stop them from becoming pregnant. It is not a good idea to spay cats that are in heat, because they are vulnerable to increased blood loss.
Kittens as young as 8 weeks old are often spayed in animal shelters so that they are more suitable for adoption. Cats should be spayed so that they do not become pregnant from non-neutered male cats, adding to the already out-of-control feline population. Spaying reduces the risk of cats developing breast cancer. It also eliminates the risk of them developing uterine or ovarian cancer.