Cat Pregnancy Stages

mother cat and her kitten
Nenov / Getty Images

Responsible pet ownership involves spaying and nurturing cats. Not only does spaying reduce the number of unwanted cats, but it also protects your own cat from contracting various diseases, like cancer, that can occur in the reproductive system. However, if you're the owner of a purebred cat whose kittens are in high demand, or you've taken on a pregnant stray, understanding the stages of pregnancy will ensure a healthy gestation period.


In order for a cat to conceive, she must first be fertile, or "in heat." An unspayed cat's fertility stage occurs every two to three weeks and even more frequently during spring and summer, as the sunlight triggers the release of hormones that activate ovulation. When your cat is bleeding, she is ready to mate and her eggs will accept fertilization for approximately ten to fourteen days. 

The fertilization of a cat's egg (ovum) involves several steps. Each step results in a new stage in the embryo's development and implantation in the lining of the uterus. This process occurs roughly two weeks after fertilization, at which point your cat may be experiencing morning sickness and a change in eating habits. 

Embryo Development

By the third week of gestation, as the embryos start to develop, your cat will gain weight and increase her intake of food. This marks the beginning of organ development in the embryos and creates a surge of hormones in your cat.

At this time, your cat's nipples may become swollen and darker in color. 

As the embryos continue to develop, the highly-evolved cells of the head (cranium) and body (thoracic region) develop first. The embryos float within a fluid-filled cradle of two sacs, one containing water, protein, sugar, salts, and fat to feed them, and the other filled mainly with excretory product.

 The placenta (the attachment between the maternal and fetal bloodstream through which oxygen, nutrients, and fetal waste interchange) develops later. 

Fetus Development

At approximately 4 weeks, when most of the organic structures have been formed, the embryos become a fetuses and the first trimester is completed. From now until birth, the growth of the fetuses will be your cat's main objective, requiring a great deal of her body's energy. Make sure to provide as much high-quality food as she'll eat during this stage. This is also the time when a veterinarian or trained professional will be able to feel the baby kittens inside her abdomen. 


As your queen nears her due date (approximately eight weeks from fertilization), she will exhibit clues to the arrival of kittens. This includes nesting—snooping around in closets and secluded areas for an appropriate place to bear her kittens. The time is ripe for you to prepare an area in a private place, with a box or basket lined with soft towels. While she may decide, instead, to give birth on the cold, hard floor of your bathroom, at least you tried to accommodate her needs.

Increased affection is another sign of impending labor. Your cat may want to be around you all the time.

But it could go the other way, as well (hormones are known to do crazy things). A previously affectionate cat may become withdrawn and seek solitude. Either personality change is completely normal.

About twenty-four hours before birth, your cat may have milky discharge coming from her nipples. This indicates "go time"—kittens are on their way.

Cat Care During Pregnancy

If you are fostering a pregnant cat or have welcomed a stray into your home, take her to the vet for a "well-check" immediately. Make sure they test her for FeLV (feline leukemia virus) and FIV (feline immunodeficiency virus) and discuss the pros and cons of vaccinating during pregnancy.

Assuming your cat is healthy, proper care during pregnancy includes a diet high in nutrients, along with fresh, clean water. She should also be kept indoors at all times.

During the final twenty days, switch your pregnant cat to a premium-quality kitten food and continue feeding her this way until after the kittens are weaned.