Do cats get their period?

Cats have their heat cycles. A queen would go in and out of its heat cycle several times a year. Some would even have a continuous heat cycle especially during early spring. These animals though do not get their period. Menstruation, commonly called period is the shedding of the uterine lining. Some female mammal species would have periods or vaginal bleeding. Female humans menstruate. Vaginal bleeding during the heat cycle is seen in dogs too but not in cats. This condition is favorable for cat owners because there will be no need to clean the bloody mess the pet has made on the floor, on the white seat cover or on the light colored rug. However, cat parent can’t help but wonder why their pets don’t get period given the fact that cats and dogs practically have the same reproductive organs and anatomical structure.

Female cats go into heat several times during the breeding season. Female cats usually have their first heat cycle between 5 to 9 months in age. Some cats would even reach puberty much earlier. A cat’s heat cycle has four stages – anestrous, proestrus, estrus and metestrus. Unlike male cats that are always ready to mate, female cats would only be receptive to the sexual attention of a male cat if it is in the estrus stage. Thus no sexual activity will occur during the anestrous, proestrus and metestrus stages. In dogs, vaginal bleeding and swelling of the vulva are signs that the animal is in the proestrus stage. The dog will allow to be mated when the vaginal discharge becomes more yellowish and less bloody. Cats do not get their period. However, a cat that is ready to be mated will show behavioral changes. The queen will be more vocal and would tend to incessantly call. The cat would show a more affectionate behavior to its owners.

Owners of female cats are glad of the fact that they have no need to use panty liners or mini pads on the pet to avoid blood spots in the house. Some owners may not even realize that the pet does not get a period. Other cat owners though would wonder why. A period (menstruation to us humans) is basically the shedding off of the endomitrium or the uterine lining. Every heat cycle, eggs will travel down the fallopian tube but only the dominant egg will reach the uterus and wait to be fertilized by the sperm. Prior to every heat cycle, the body would prepare the uterus for possible fertilization of an egg. The uterine walls will be made thicker with blood vessel-rich glandular tissues to create an ideal environment that will support the growing fetus. If the egg was not fertilized because the animal was not mated or a physical condition prevents conception, the body has to make a spring cleaning to prepare for the next heat cycle. The egg as well as the uterine lining will be shed.

Cats do not get periods because these animals are induced ovulators. Unlike other mammals that ovulates and releases eggs regularly, ovulation or the release of eggs would only occur if the cat is mated. This means that the body would have no reason to prepare the uterus beforehand. As there is no thickening of the uterine walls, no menstrual fluid that contains blood, vaginal secretions, pieces of the endometrial tissues and cervical mucus needs to be shed. Another reason why cats do not get periods is because they belong to the species that reabsorb the endomitrium if fertilization of the eggs did not occur. Because cats do not get periods, a vet’s attention would be necessary if the pet is noticed to have bloody vaginal discharge as it can be a symptom that the cat has an underlying medical concern.