When a cat is spayed, the surgeon removes both ovaries and the uterus. This procedure, called an ovariohysterectomy, is the standard spay method used in the United States and eliminates the organs responsible for producing eggs, sex hormones, and supporting pregnancy.
What Gets Removed
A female cat’s reproductive tract includes the vulva, vagina, cervix, uterus, two oviducts (fallopian tubes), and two ovaries. During a standard spay, the veterinarian removes the ovaries, the oviducts, and the uterus, leaving the cervix, vagina, and vulva intact.
The ovaries are small glands that produce eggs and two key hormones: estrogen, which drives egg development and triggers heat cycles, and progesterone, which prepares the uterus for pregnancy and the mammary glands for milk production. Both hormones also shape sexual behavior, including yowling, restlessness, and the urge to roam.
The uterus is where kittens would develop during pregnancy. In cats, it has a Y-shaped structure with two long “horns” branching off a shorter body. Each horn connects to an ovary via an oviduct. The entire structure is removed during a standard spay.
Ovariohysterectomy vs. Ovariectomy
There is actually a second, less common version of the surgery. An ovariectomy removes only the ovaries, leaving the uterus in place. This approach is standard practice in much of Europe, while American veterinarians have traditionally performed the full ovariohysterectomy. The difference is largely a matter of regional tradition rather than medical evidence. Research from the Veterinary Information Network confirms that both techniques are considered acceptable for healthy cats, and that ovariectomy can reliably replace ovariohysterectomy as an elective sterilization method.
The reasoning behind leaving the uterus is straightforward: without ovaries producing progesterone and estrogen, the uterus becomes hormonally inactive and poses very little health risk. However, if a cat already has a reproductive tract disease, such as an infected uterus, the full ovariohysterectomy is the clear choice.
How the Surgery Works
To reach the reproductive organs, the surgeon makes a small incision in the abdomen, typically about 2.8 centimeters long (just over an inch). There are two common approaches: a ventral midline incision along the belly or a flank incision on the cat’s side. Both use roughly the same incision length. The midline approach is more common in the U.S., while the flank approach is sometimes preferred at high-volume spay clinics because it can be easier to monitor for post-surgical swelling.
Once inside, the surgeon locates the ovaries and uterus, ties off the blood vessels supplying them, and removes the organs. The internal layers of the abdominal wall are closed with absorbable sutures that dissolve on their own over weeks to months. The outer skin may be closed with absorbable sutures, surgical glue, or removable stitches depending on the clinic’s preference.
What Changes in Your Cat’s Body
Removing the ovaries eliminates the source of estrogen and progesterone. This means your cat will no longer go into heat, which in unspayed cats can happen as often as every two to three weeks during breeding season. The behaviors that come with heat cycles, including loud vocalizing, restless pacing, and attempts to escape outdoors, stop once hormone levels drop.
Many owners notice their cat becomes calmer and somewhat less active after spaying. This is a direct result of lower estrogen levels reducing the drive to roam and seek mates. Metabolism also slows slightly, which is why spayed cats can gain weight more easily if their food intake isn’t adjusted.
Health Benefits of Removing These Organs
Spaying eliminates the risk of pyometra, a serious bacterial infection of the uterus. Pyometra develops when progesterone from the ovaries causes changes in the uterine lining that make it vulnerable to infection: the hormone stimulates gland growth, increases secretions, closes the cervix, and suppresses the uterine contractions that would normally help clear bacteria. Among intact female cats, pyometra affects roughly 17 out of every 10,000 cats per year. That may sound small, but the infection is life-threatening and almost always requires emergency surgery to remove the uterus anyway.
Spaying also reduces the risk of mammary tumors, which are malignant in the majority of feline cases. The protective effect is strongest when spaying happens before one year of age. Cats spayed after two years of age may actually face a higher mammary tumor risk compared to intact cats, based on at least one study, suggesting that the cumulative exposure to reproductive hormones is what drives risk.
Recommended Timing
The American Animal Hospital Association endorses the “Fix Felines by Five” initiative, recommending that cats be spayed by five months of age. Female kittens can enter their first heat cycle as early as four months old, though five to six months is more typical. Spaying before that first cycle captures the strongest cancer-prevention benefit and eliminates any chance of an accidental pregnancy. Kittens sterilized at this age recover quickly, often returning to normal activity within days.