Fading Kitten Syndrome

Katie Ryan, DVM
By Katie Ryan, DVM on Nov. 24, 2021

In This Article


What Is Fading Kitten Syndrome?

Caring for a precious newborn kitten can be a rewarding experience, but it also can be heartbreaking if a kitten experiences Fading Kitten Syndrome. 

Fading Kitten Syndrome refers to a kitten’s failure to thrive during the period between birth and when they wean from their mother or from a bottle for hand-fed kittens. This period lasts about four to five weeks (when a kitten is most vulnerable to sickness).

Sadly, Fatal Kitten Syndrome is usually fatal, but recognizing the warning signs early can allow your veterinarian to intervene.

Signs and Symptoms of Fading Kitten Syndrome

Kittens that fail to meet normal development milestones may be experiencing Fading Kitten Syndrome. Some of these milestones include:

  • Ability to turn over from their back by day 3 of birth

  • Ability to support themselves on their feet by 2 weeks

Other signs and symptoms for the pet parent to watch for:

  • Constant noises that indicate distress (such as whining or crying), even after feeding

  • Gradually worsening lethargy (lack of energy)

  • Lack of appetite

  • Poor suckling reflex

  • Weakness

  • Inability to gain weight

  • Labored breathing

  • Vomiting

  • Diarrhea

  • Nasal or eye discharge

A delay in evaluation and treatment could result in low blood sugar, dehydration, low body temperature, and death. Even with treatment, oftentimes these kittens will sadly die. 

Causes of Fading Kitten Syndrome

Fading Kitten Syndrome has numerous causes, and often more than one is to blame. For example, having a large litter, trouble during birthing, or poor nurturing instincts or nutrition on the mother’s part can cause kittens to fail to thrive. 

Genetics can play a role as well. If a mother cat (called the queen) has a blood type that differs from her kitten, her maternal antibodies may attack the kitten’s red blood cells, causing anemia that can lead to Fading Kitten Syndrome. This condition is called neonatal isoerythrolysis.

In general, causes of Fading Kitten Syndrome include:

  • Trouble during birthing

  • Lack of maternal antibodies (cells that help protect kitten’s immature immune system)

  • Bacterial or viral infections

  • Parasites

  • Malformations present at birth (e.g., heart defects, gastrointestinal defects, brain defects, lung defects, etc.)

  • Low birth weight

  • Trauma

  • Maternal neglect

  • Malnutrition

How Veterinarians Diagnose Kitten Fading Syndrome

A veterinarian will examine a newborn kitten in the first few weeks of life (from birth to weaning) to determine if he is thriving. If your veterinarian does not see a kitten reaching certain milestones, they will do their best to determine the underlying cause of why the kitten is declining.

Sometimes veterinarians cannot determine a cause before death or humane euthanasia, and a necropsy (or autopsy if the kitten passes or is euthanized) is required for definitive diagnosis. Tests may include bloodwork along with fecal and/or urine evaluation.

Treating for Kitten Fading Syndrome

Fading Kitten Syndrome may be treatable if an underlying cause can be identified in time, but often this is not the case. For example, some bacterial infections can be treated if caught early enough, while some congenital (condition present at birth) defects such as heart, gastrointestinal, or brain defects may not, especially if the kitten’s quality of life would be poor. 

Treatment includes supportive care while the veterinarian works to identify an underling cause. Supportive care usually includes fluids, dextrose to support blood sugar levels, antimicrobials, nutritional support, oxygen support, and body temperature support. 

Recovering from Kitten Fading Syndrome

Recovering from Kitten Fading Syndrome is possible if an underlying cause can be identified in, and treatment started in time. Unfortunately, Fading Kitten Syndrome is fatal more often than not, with the highest rate of mortality being in the first week of life. 

If a kitten does survive this crucial period and grows stronger, long-term management is aimed at proper nutrition, providing sanitary conditions and preventative health care, and close monitoring to ensure they gain weight. 

The long-term outlook for kittens that recover is good, unless there is a congenital or chronic viral infection, such as FIV (feline immunodeficiency virus) or feline leukemia, that affects the kitten’s life expectancy. 

Fading Kitten Syndrome FAQs

Can a kitten survive Fading Kitten Syndrome?

Possibly, although more often than not it is a fatal syndrome.

How do I help my kitten with Fading Kitten Syndrome?

Ensure proper sanitary conditions, appropriate environmental temperatures, monitor nursing behavior closely, and monitor for appropriate weight gain. 

If you’re breeding cats, preventative measures include screening queens (adult intact female cat) and tomcats (adult intact male cat) for infectious diseases, providing appropriate preventative health care for vaccines and parasite control, ensuring proper nutrition, and blood typing prior to breeding. 

What age does Fading Kitten Syndrome start?

Fading Kitten Syndrome can start immediately after birth up until the age of weaning (about four to five weeks of life).

How do kittens get Fading Kitten Syndrome?

Fading Kitten Syndrome may be caused by a long list of conditions including congenital abnormalities, infectious causes (e.g., viral, bacterial, parasitic), maternal causes (e.g., trauma, neglect, malnutrition), low birth weight, trouble during birthing, and neonatal isoerythrolysis (a condition in which the maternal antibodies passed in the first milk to help protect the kitten actually attack the kitten’s own red blood cells). 

Is Fading Kitten Syndrome genetic?

Congenital defects leading to Fading Kitten Syndrome can be genetic. 

Why does Fading Kitten Syndrome happen?

Fading Kitten Syndrome is a term for any kitten that fails to thrive. If you are concerned that your newborn kitten may be failing to thrive, please have them evaluated by a veterinarian as soon as possible.


Featured Image: iStock.com/Iuliia Alekseeva

Katie Ryan, DVM


Katie Ryan, DVM


Dr. Ryan is a 2012 graduate of Michigan State College of Veterinary Medicine. Following graduation, Dr. Ryan enjoyed a brief stint in...

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