Early Age Spay/Neuter

June 24, 2025

Early Spay/Neuter Has Many Positive Effects

Dr. Karen Thomas

For many years veterinarians were taught that cats should not be altered before reaching sexual maturity. For females, that was considered to be about six months old and for males it was at least eight months old. It was once believed that neutering male cats before eight months old would mean the urethra would not fully develop and the cat would be prone to urethral blockage. Of course, as many mature intact cats suffer from urethra blockage, that consideration was disproven. Furthermore, it was thought that hormones were necessary for proper development of bones and joints. While that may be true for large breed dogs, no such association has been proven for cats.

An additional factor was that available anesthetics were intravenous injectable barbiturates and/or halothane inhalant anesthetic gas which worked too slowly to be of good use when anesthetizing by face mask. In most cases, anesthesia was induced with a syringe strapped to the leg so that additional anesthesia could be given if needed. That was difficult indeed to perform on a small kitten or puppy.

By the mid 1990s, articles began to be published detailing research into the risks and benefits of prepubertal gonadectomy, or “early age” spay and neuter. In part, this may have been fueled by the development of safe and effective anesthetics that could be administered intramuscularly. Anesthetic “cocktails” using combinations of drugs at very low doses are now in common use, and newer inhalant anesthetics such as isoflurane and sevoflurane may be administered via face mask or anesthetic chamber.

There is now a considerable body of research indicating that early age spay/neuter in cats is not only safe but also helpful in many ways. The benefits to the community at large are enormous. Many well-meaning people who adopt cats from animal control facilities or obtain kittens from routine sources hold them for the “proper” age for neutering. Sadly, animals adopted intact from a shelter or animal control often do not get fixed in a timely manner, even when the adopters are subject to fines if they do not follow the required procedures. In cases where people were required by contract to make sure their pedigreed cats did not reproduce, accidental or intentional pregnancies sometimes occurred. Some owners assumed that parents would not breed with offspring or that siblings would not breed with each other. Some wanted their children to see the “miracle of birth.” Others were just too busy or lacked the funds to follow through with the operation. In addition, many people were not aware that cats can become sexually active before six months of age. For all these reasons, failure to perform early age spay/neuter results in many unintended litters. These litters significantly add to the problem of pet overpopulation and overcrowding at shelters.

Studies show that cats being sexually active creates a high risk for them being surrendered to shelters. As many as 80% of cats surrendered to shelters are intact. Such unwanted behaviors as roaming, calling, and spraying are curtailed by early neuter of male cats. Spays and neuters performed on kittens from eight to sixteen weeks of age are faster than when these surgeries are performed on mature cats. The incidence of complications is lower and the recovery of the patients is quicker. Prepubertal spaying virtually eliminates mammary tumors in older females, a condition that is highly malignant in cats.

Breeders of pedigreed cats now often have their kittens altered before sending them to new homes, and most rescue groups, humane societies, and animal control facilities do the same. The practice of pediatric spay/neuter is endorsed by the American Veterinary Medical Association, the Feline Veterinary Medical Association, the American Animal Hospital Association, and both the Cat Fanciers’ Association (CFA) and The International Cat Association (TICA) as well as many other interested parties.

 

EveryCat (then known as The Winn Foundation) funded one of the first studies regarding the effects of early spay/neuter in cats’ physiology and behavior:  https://avmajournals.avma.org/view/journals/javma/209/11/javma.1996.209.11.1864.xml?tab_body=pdf

Reference: Olson PN, Kustritz MV, Johnston SD. Early-age neutering of dogs and cats in the United States (a review). J Reprod Fertil Suppl. 2001;57:223-32. PMID: 11787153.