Do cats get periods?

Menstruation which is commonly called “period” is one of the signs that a girl is turning into a woman. Menstruation is characterized by the shedding of the endometrium or the uterine lining. A “period” that typically happens every month is characterized by the shedding of menstrual fluid that contains blood, vaginal secretions, cervical mucus and the pieces of the endometrial tissues. Most mammals with placenta would go through a menstrual cycle. However, not all mammals would shed menstrual fluid. Cats get heat cycles but these are one of the animals that do not show the obvious signs of being in a “period”. The swelling of the vagina and the bloody vaginal discharge that are manifested by dogs in the heat cycle are not seen in cats.

Cats do have heat cycles but no obvious bleeding will be noticed. Cats share the same reproductive system with humans. However, there is one significant difference. While human females would shed the endometrium in a process called menstruation or period, cats would reabsorb the endometium if the eggs were not fertilized. Human ovaries will release an egg every month or every menstrual cycle. Approximately 20 eggs will travel down the fallopian tube but only the dominant egg will be released for ovulation. This egg will wait in the uterus to be fertilized by a sperm. The uterine lining is thickened with glandular tissues that are rich in blood vessels to create an optimal environment that will support the growth of the fetus. Menstruation or “period” will occur if the egg was not fertilized. The body would need to dispose of the egg. The endometrium has to be shed as well to prepare for the next cycle.

During estrus, the female cat will be receptive to the attention of the male cat. A queen willing to be mated will assume the mating position when a tom is near. Cats are induced ovulators. An egg will not be released until the female cat is mated and stimulated. A queen ready to be mated will raise the tail to one side to accommodate the entry of the male cat’s penis. To hold on, male cats would bite the female at the back of the neck. After the copulation, the queen would scream when the tom withdraws the barbed penis. The barbed penis as well as the biting of the scruff of the neck is believed to stimulate the queen to ovulate. Ovulation will occur 20 to 50 hours after the queen is mated. Once fertilized, the eggs will travel via the uterine horn and implant on the uterine lining.

Being induced ovulators is one of the reasons why cats don’t get periods. As ovulation will only occur when the cat is mated, there is no reason for the body to thicken the endometrium with glandular tissues beforehand. Moreover, cats would not go through a menstrual cycle because these animals would reabsorb the endometrium if the mating did not result to pregnancy. The estrus cycle in dogs is signified by the bleeding of the vulva and bloody vaginal discharge. Cats would not show obvious signs of being in the estrus cycle. The cat though would manifest behavioral changes. A queen in heat would be more affectionate. Calling and kneading and sidling around humans are signs that the cat is in heat. The swelling of the vulva as well a bloody vaginal discharge are symptoms of an underlying health concern. The cat does not have a period and it would be wise to get the pet to a veterinary facility for proper diagnosis and treatment of its condition.