Cats are amazing animals capable of producing multiple litters of kittens every year. Unlike dogs, cats will continue to go into heat until they are pregnant. Therefore, if a pet parent isn’t interested in breeding their cat, they should have her spayed to relieve her from the constant desire to mate. 

Female Cat Heat Cycle

Reproduction in cats begins with a breeding season. Breeding seasons for cats vary based on the geographical location of the cat. Places with warmer climates have longer breeding seasons, while cooler climates have shorter breeding seasons. 

Cats can have several heat or estrous cycles during a breeding season — meaning they are polyestrous. Heat cycles last an average of six days. If a cat doesn’t become pregnant during their heat cycle, they will go back into heat approximately one to six weeks later. 

Pet parents wanting to breed their cat can do so anytime while their cat is in season. Cats are induced ovulators, meaning the act of breeding will stimulate the release of eggs while the cat is in season.  

Behavioral Changes

When a cat is in heat — or season — pet parents may notice various behavioral changes. These changes may be alarming at first, but they are normal.

Some behavioral changes a pet parent might notice when their cat is in season are:

• Increased vocalizing and/or howling
• Extremely affectionate
• Rubbing against their pet parent or other people
• Raising their hips and rear 

Fetal Development

Cats have a short gestation period of about nine weeks. Pet parents can expect the following to happen during those nine short weeks.

• Week 1: Fertilization occurs one to 10 days after mating. 
• Weeks 2 through 4: Fertilized eggs implant, and organs begin developing. Around 25 days, an ultrasound can be done to check for kittens.
• Week 5: Organs continue to develop, and the fetuses rapidly gain weight. Pet parents should offer the mother cat food with extra calories to help support the growing fetuses.
• Week 6: Tissues and claws develop.
• Week 7: Bones and hair begin to develop.
• Week 8: Bones harden and are detectable on an X-ray. Also, the mother cat’s teat will begin to fill with milk in preparation for the kittens. 
• Week 9: The kittens are fully developed, and the mother cat can go into labor at any time.

Pet parents can help their cat prepare for birth by creating a comfortable birthing area. The location of the birthing area should be warm, secluded, and draft-free. 

Stages of a Cat in Labor

Cats go through three stages of labor. The first stage is the longest and can last around 36 hours. The second stage of labor can last various amounts of time depending on how many kittens the mother births. 

Pet parents can expect the following during each stage of labor:

• Stage 1: Contractions begin, and the mother cat’s temperature drops. She will likely start making multiple trips to the kittening bed and seem not to get comfortable. She might also begin panting and making vocalizations. 
• Stage 2: Contractions get stronger, and a kitten enters the pelvic canal. The mother cat appears to be straining, and the kitten is delivered within five to 35 minutes.
• Stage 3: The “after-birth” passes, and the mother separates the membrane from the kitten. 

The mother cat will go back and forth between stages two and three until all the kittens are born. Kittens are usually born 10 to 60 minutes apart. If two kittens are delivered quickly, the after-birth may be delayed. 

As soon as a kitten is born, the mother cat will begin licking the kitten’s nose and mouth to clear any fluid and stimulate breathing. If the mother doesn’t break the membrane around the kitten after about a minute, the pet parent can help by gently rubbing the kitten with a clean towel.  

Birthing Complications

Most of the time, cats don’t have any problems birthing healthy kittens by themselves. However, a few complications can occur, and pet parents need to be ready to assist. When a cat has a difficult birth, it is called dystocia. 

Dystocia usually occurs when a kitten gets stuck. When a kitten is stuck, the mother cat can become exhausted and dehydrated. At this point, she will need assistance birthing the kitten. 

Signs the mother cat needs veterinary care include:

• Strong contractions that last more than 30 minutes and do not produce a kitten.
• A kitten is visible and trapped in the birth canal.
• The mother cat is lethargic and has a rectal temperature over 103 degrees Fahrenheit.
• Gently pulling on a trapped kitten causes the mother cat pain.

After all the kittens are born, the pet parent may want to get an X-ray of the mother cat to make sure all kittens are out.