Non-spayed female cats will go into "heat" or estrus seasonally in the spring and fall and may go into heat several times during the season. The period of heat lasts an average of about a week, but can vary from three to 14 days. Your cat will exhibit many behaviors during estrus that you should expect. The only cure for these behaviors is to have the cat spayed.
Five Stages of the Feline Estrus Cycle
- Proestrus: Not many signs are seen in the cat for this stage. The female is attractive to the male but unwilling to mate. Length: one to two days.
- Estrus (Heat): This is when the female cat is receptive to the male. External signs such as a swollen vulva are not as obvious in the cat as they are in the dog. The main signs seen are behavioral—loud vocalizing, rolling on the floor, elevating the hindquarters, and possibly a decrease in appetite. Many people have confused the signs of the feline estrus phase as signs of being in pain. Length: three to 14 days (average of one week). If the female is not mated, she may go back into heat within several days.
- Interestrus: The period between estrus cycles if the female isn't bred. Length: two to three weeks.
- Metestrus (or Diestrus): Period after estrus or mating. Length: 30 to 40 days. If pregnant, pregnancy lasts on average 60 to 64 days in the cat.
- Anestrus: Period of inactivity (sexual and hormonal) between estrus phases. Length: two to three months.
Facts About Feline Estrus
- The first estrus cycle usually occurs by age 6 to 12 months; for some cats as early as 4 months of age, for others not until age 12 months or so.
- Cats are considered to be seasonal breeders, most often showing signs of mating behavior in the spring and fall.
- Cats are induced ovulators, meaning that they only ovulate (release an egg from the ovary) if mated.
- If not mated (no ovulation), the estrus phase of the cycle will return in one to three weeks.
- Multiple matings produce more ovulations; more than one male can be the sire of a litter.
- Cats can get pregnant during their first heat cycle, but this is not advisable as a 6-month old cat is not yet fully grown/mature, and complications for the mother and the kittens are more likely.
- An intact (not spayed) female cat of reproductive age is called a queen.
- Cats do not shed their uterine lining as humans do, so you should not see a bloody discharge.
What to Expect When Your Cat Is in Heat
- Your cat will be extremely eager to mate due to the effects of her hormones.
- She yowls to attract attention and show she is eager to mate, although it can seem as if she is in pain.
- She will pace and may attempt to run out the door.
- She will rub against you. If you pet her, she may assume a mating position.
- She may lick her genitals. Note that bleeding is rare and you may want to contact your vet.
- She may mark her territory by spraying.
These are all normal behaviors when in heat, but they can make an intact female cat difficult to live with during estrus. Your vet may be able to provide hormone injections, but the best solution is to have your female cat spayed.
Spaying Your Cat at the Right Time
For cats that are pets, it is recommended to spay them before the first heat, eliminating the risk of accidental pregnancy and reproductive diseases later on in life.
Cats may be spayed while in heat (or pregnant), but there is an additional risk due to the engorged vessels and tissue of the reproductive tract—a higher chance of bleeding during surgery or other complications. The cost of surgery while in heat or pregnant is often higher as well.