Fading Kitten Syndrome

Tiny grey tabby kitten in hands
Stefanie Baum / Getty Images

Fading Kitten Syndrome (FKS) is not a disease, but rather a collection of symptoms that develop. Often the very first symptom you observe is the unfortunate unexplained death of your very young kitten. Because of this, FKS has been compared to Sudden Infant Death Syndrome (SIDS) in human babies.

With kittens however, an extremely perceptive caregiver might be attuned to the symptoms and might be able to take actions to prevent immediate death in a kitten. Depending on the causes, they may also allow the kitten to survive indefinitely. People who rescue and foster pregnant cats and/or foster kittens should take time to learn to spot the symptoms of FKS as the offspring of stray and feral cats are particularly prone to this condition. Since FKS is so common, many people involved in feline rescue believe in the spaying of rescued pregnant cats for exactly this reason.

Fading Kitten Syndrome Timeline

The first six to eight weeks of a kitten's life are the most likely for a kitten to develop Fading Kitten Syndrome. Many experts state the first 12 weeks of a kitten's life are when they are at the highest risk, but the first few weeks of a kitten's life are especially the most concerning. 

Fading Kitten Syndrome Indicators

There are some indications that a kitten may be at risk for developing Fading Kitten Syndrome. The identifications to watch for include:

  • Extremely low birth weight - Kittens that develop FKS are often the runt or smallest one of the litter. They have a low birth weight and are not as active as their litter mates.
  • Unable to nurse properly - Healthy kittens are able to nurse almost immediately after birth. A fading kitten, on the other hand, might be described as the "hind teat kitten," as it is often not strong enough to grasp and suckle the mother cat's nipple. During the first 72 hours or so of nursing after birth, the kitten is receiving a special milk, which provides essential nutrients and also whatever antibodies the mother cat may have acquired called colostrum. This colostrum gives the kitten passive immunity to allow them to grow and thrive until they can receive vaccinations and stop nursing. If a kitten does not get colostrum and fails to nurse, they will need to be bottle fed and are more likely to develop FKS.
  • Abandonment by the mother cat - Mother cats can sense when there is a weak kitten and may abandon the weakest one. This is a defense mechanism to protect the other kittens and an instinct of many animals.
  • Hypothermia - Since newborn kittens don't have the means to regulate their own body temperatures, they depend on their mom for warmth. Therefore, if the mother cat has abandoned one of its kittens, this kitten will quickly develop hypothermia. The hypothermic kitten will be lethargic and its mouth and gums will be a bluish shade rather than a healthy pink. Death will likely occur soon thereafter, unless human intervention occurs.

Causes of Fading Kitten Syndrome

There are a number of causes of FKS and in order to treat the symptoms, you will need to know the cause of them.

  • Disease or malnutrition of the mother cat during gestation - If this is the first litter of the queen during the current season, it may have enough food available to it to grow healthy kittens. But since a cat can conceivably give birth to up to five litters of kittens within a year, it's easy to see how it could become malnourished and sick by the end of the year. Lack of adequate nutrition will weaken the mother cat, making it more susceptible to disease. This combination does not bode well for late season kittens, resulting in stillborn kittens, kittens born with disabilities, and kittens with FKS. For these reasons alone, it is imperative to take a suspected pregnant cat to the veterinarian for a prenatal check-up and to discuss your options with your vet.
  • Infectious diseases - There are a number of infectious diseases that can quickly effect an entire litter of kittens. Because of this, it is important to keep the litters of a stray or feral queen completely separated from any household cats and to spay and neuter as many stray cats as you can.
  • Fleas and other parasites - Fleas bite cats, so an infestation on a kitten can quickly cause anemia or give the kitten a blood-borne parasite, both potentially fatal to a young kitten.

Edited by Adrienne Kruzer, RVT