Female cats will undergo their first estrous, or heat cycle, when they reach puberty. Puberty can occur as early as four months, but the typical age is somewhere between six and nine months of age. Estrus is the period during the heat cycle when a female is receptive to mating with a male, and can become pregnant during this time. If the female does not become pregnant, she will continue to go through the estrous cycle until she either becomes pregnant or is spayed.
Cats in heat will exhibit signs that can be quite annoying for owners. If they are spayed, those signs should not be present. However, there are a few conditions where that may not be the case. Here, we will discuss the signs of heat in cats, causes of heat signs in a spayed cat, and why treatment is important if your cat is in heat after a spay.
Signs of Heat in Cats
Unlike dogs, the female cat in heat does not have a vaginal discharge. Her signs are typically behavioral in nature. The more common signs an owner may notice is that she becomes unusually affectionate and quite vocal. She may urinate or spray in the house in an attempt to let local tomcats know she is receptive to mating. She also has a tendency to stick her rear in the air and wiggle her back end when she is petted. If a cat that has been spayed is exhibiting signs of being in heat, this could be an indication there are active estrogen hormones in her system. If you notice any signs of heat in your spayed cat, please speak with your veterinarian.
Common Signs of Heat in a Cat
- Showing more affection
- Rubbing face on owner or objects
- Raising hind end into the air
- Attention-seeking behavior
- Frequent urination or urine marking
- Roll on floor
- Begging to go outside
Causes of Heat Signs in Spayed Cats
Ovarian Remnant Syndrome
When a cat is spayed and the owner starts to notice signs of heat, the first thought may be that the surgeon left something behind, but that is usually not the case. Some females possess accessory ovarian tissue separate from the main ovary and this tissue becomes active only after the main ovaries are removed. Some cats actually grow ovarian tissue down the length of their ovarian ligament, which is cut during the spay surgery but not fully removed because it is not visible to the naked eye.
Furthermore, if an ovary touches the abdominal wall, cells are able to attach and vascularize creating a new, smaller ovary. In many cases, the original spay surgery was performed months or even years before. These secondary bits of the ovary are growing during this time. Owners may not notice a change in their cat's behavior, until they have achieved sufficient hormone-producing power. Signs of heat will then be more apparent. Once it has been determined that a pet has an ovarian remnant, surgery should be performed to locate and remove it.
After a cat is spayed, a small stump of uterine tissue inside the abdomen where the tract has been tied off may remain. As long as there are no female hormones available, the stump will be inactive and cannot develop a pyometra, an infection of the uterus. If hormones are circulating, a pyometra can develop in the stump and clinical signs of heat may be observed. Vaginal discharge and a distended abdomen may also be noted, in an otherwise healthy spayed cat. If a stump pyometra is suspected, exploratory surgery may be necessary to remove it. Your veterinarian will help determine the right treatment plan for your cat.
Adrenal tumors can produce hormones. Unfortunately, these can be difficult to remove, but exploratory surgery should help differentiate between this and an ovarian remnant. In this situation, signs of heat are constant, they don't cycle as with ovarian tissue.
Topical estrogen-containing creams are available for human use and unfortunately may end up on the user's hands or arms, where a cat can lick them off. A female cat exposed to these creams can potentially manifest signs of heat but will not show a predictable hormone cycle. The best way to avoid a cat's access is for owners to use gloves during application and to make sure to wash hands and to keep the area of skin containing the hormone, away from them.
Why is Treatment Important?
Hormones can be harmful. Long term exposure to female hormones can cause mammary cancer. Also, if even a small piece of uterus persists after being spayed, chronic infection can ensue. So the best way to avoid the serious repercussions of female hormones is to speak with your veterinarian if you notice your spayed cat is experiencing signs of heat. They will work with you to determine what is causing the behavior change and identify the best way to treat them.
Barnette, Catherine. Ovarian Remnant Syndrome In Cats. VCA Animal Hospitals, 2020.
Pyometra. American College of Veterinary Surgeons, 2020.
Daniel, Gideon et al. Clinical Findings, Diagnostics And Outcome In 33 Cats With Adrenal Neoplasia (2002–2013). Journal Of Feline Medicine And Surgery, vol 18, no. 2, 2015, pp. 77-84. SAGE Publications, doi:10.1177/1098612x15572035