menu iconknow your dna logosearch icon
Birth Defects In Cats & Newborn Kittens
Updated on January 10, 2023
Back to top
back to top icon
Cat Testing
Birth Defects In Cats & Newborn Kittens

It’s relatively common for cats to be born with birth defects.

These defects include abnormalities of function, structure, or metabolism at birth. Many of these defects resolve on their own. But in some cases, they require medical attention to correct, or they are present for the cat’s entire life.

Congenital defects in kittens tend to be rare.1 Some research has shown pedigreed cats have a higher risk of developing a defect. However, the risk is statistically insignificant. Defects don’t seem to affect one specific breed over another.

Birth Defects In Cats & Newborn Kittens 2

Defects can cause physical impairment; in some cases, serious defects are fatal

Birth defects might be obvious at birth, subtle and apparent only when the cat doesn't develop properly. Some are detected when cats show clinical signs of a health problem or are found only with diagnostic testing. Other problems, like a heart defect, are diagnosed later on.

What are some of the defects cats are at risk for?

Blood Type Incompatibility

It’s dangerous for cats with different blood types to breed. If a blood type B female cat breeds with a blood type A male cat, the litter is at risk of dying shortly after birth. This is due to the incompatibility that destroys the kitten's red blood cells.

Cleft Palate

A cleft palate occurs when kittens are born with an opening in the roof of their mouths due to the two sides never fusing. Many cat owners wouldn’t think to look inside the top of their cat’s mouth.

Cleft palate is often discovered due to the condition’s corresponding symptoms, which include:

  • Coughing
  • Runny nose
  • Difficult nursing

Cleft palate is usually inherited. Some breeds are more prone to it than others, including:

  • Siamese
  • Ragdolls
  • Norwegian forest cats
  • Ocicats
  • Persians
  • Savannahs

Other factors that put kittens at risk of cleft palate include:

  • Exposure to certain chemicals
  • Exposure to cortisone
  • Medications
  • Excessive intake of vitamins A and D during pregnancy

Flat Chested Kitten Syndrome (FCK)

Flat Chested Kitten Syndrome causes a kitten to develop a depression in the rib cage because of a collapsed lung.


This is also known as water on the brain. Hydrocephalus causes cerebrospinal fluid (CSF) to accumulate around the brain or blocks CSF from flowing outward. This leads to pressure around the brain.

Kittens usually develop hydrocephalus because of CSF blockage.

However, other causes of hydrocephalus in cats include:

  • Certain viruses
  • Bacterial and fungal infections
  • Parasitic migration
  • Cysts and tumors

Hypertrophic Cardiomyopathy

Cardiomyopathy is a heart disease in cats that usually leads to heart failure. Hypertrophic cardiomyopathy is the most common among all forms of congenital heart defects.

This condition is characterized by the walls of the heart becoming too thick. Congenital heart disease such as this can sometimes result in death.2

Intestines on the Outside of the Body

Kittens born with their intestines or any other organ exposed should undergo veterinarian examination immediately. In some cases, surgery can correct the defect.


Some kittens’ eyes are not grown to full size. With microphthalmia, the eyeball appears to be smaller than normal. In some cases, the eyeballs are absent. 

Open Fontanelle

The fontanelle is the soft spot on the top of the head that closes soon after birth.

It is present in humans and animals alike. The soft spot allows the skull plates to move so the baby’s head can pass through the birth canal.

It usually seals on its own within a few days or weeks of birth, but if it does not, it leaves the brain exposed to risk.

Pectus Excavatum

Some kittens are born with this unusual chest wall deformity. It’s sometimes called an inverted sternum. It is said to be caused by genetics.

However, pectus excavatum tends to develop spontaneously regardless of the cat’s breed. The condition is often diagnosed several weeks after birth or earlier if it is severe.


This potentially fatal bacterial infection affects kittens two weeks and younger.

If left untreated, septicemia could progress to a severe form, leading to liver failure, respiratory distress, kidney failure, and more.

Swimmer Syndrome

Swimmer syndrome occurs when a kitten cannot crawl or stand normally. The kitten’s hind legs are typically splayed laterally. They display what is called a frog-like posture.

Umbilical Hernia

This is the most common type of kitten hernia and occurs at the belly button.

This occurs because the umbilical ring fails to close fully. The hernia is a protrusion under the cat’s skin, especially when the cat is straining, crying, meowing, or standing.

Know Your DNA Reviews

Best Cat DNA Test

Are you curious about your cat's ancestry and health predispositions?

What Causes Birth Defects in Cats?

Most of the birth defects in cats have no known cause, but experts speculate that they're brought about by two potential causes:1

  • Some congenital cat defects are said to be caused by genetic factors from mutated genes or chromosomal abnormalities. 
  • Environmental factors like exposure to toxins, viral infections during pregnancy, nutritional deficiencies, and many more may also cause other birth defects. Taurine deficiencies are especially problematic for cats. 

Conversely, a congenital defect might come from a combination of two or more of these factors.

Are Cat Birth Defects Preventable?


There are things breeders can do to reduce the risk of kitten birth defects. Cats can now undergo genetic tests to prevent birth defects.

Basepaws can test your cats before breeding to determine if any genetic risks are of concern. It’s more difficult to prevent birth defects when you don’t know the genetic history of a cat.

To reduce the risk of birth defects, consider the following before allowing your cat to mate:

  • Is your cat’s particular breed makeup prone to birth defects?
  • Was your cat born to a litter with one or more defects, even if it does not have a defect?
  • Has your cat mated before and experienced any issues?
  • Is there anything impeding your ability to provide your cat with a healthy diet and environment once she’s pregnant?
  • Is your cat taking any drugs?
  • Is your cat up-to-date on vaccines, and will any vaccines be needed during pregnancy?

Consider a thorough health examination by a veterinary healthcare professional before breeding your cat, even if you know of no potential risks. An examination should occur before every breeding experience.

Know Your DNA Reviews

The Best Cat DNA Test

What could be more fun than learning everything there is to know about your feline friend?

Updated on January 10, 2023
Minus IconPlus Icon
2 sources cited
Updated on January 10, 2023
  1. Lowell Ackerman DVM, DACVD. “Tufts’ Canine and Feline Breeding and Genetics Conference, 2005.”, 30 Mar. 2015, Accessed 31 Jan. 2021.
  2. CDC. “Learn about Specific Birth Defects.” Centers for Disease Control and Prevention, 5 Aug. 2019,
Dr. Alam
Dr. Alam Roky
Medical Reviewer
Dr. Shamsul Alam Roky is a registered veterinarian who graduated from the Faculty of Veterinary, Animal, and Biomedical Sciences. Currently, he is working as a graduate research assistant at his university, in addition to running a private veterinary clinic named ‘Sylhet Veterinary Services” in his city.
Kelly Jamrozy
Kelly Jamrozy
Content Contributor
Kelly has experience working with clients in a variety of industries, including legal, medical, marketing, and travel. Her goal is to share important information that people can use to make decisions about their health and the health of their loved ones. From choosing the best treatment programs to improving dental and vision health to finding the best method for helping anyone who is struggling with health issues, she hopes to share what she learns through informative content.
Back to top icon