Could Spaying Be a Thing of the Past for Female Cats?

While estimates vary, there are thought to be anywhere between 50 and 70 million stray or feral cats in the US. These cats typically live in tough conditions and can cause untold damage to local wildlife. Unfortunately, those who end up in animal shelters may face euthanasia—a heartbreaking but sometimes necessary method for managing the stray population.

While spaying is a relatively risk-free surgery for female cats that helps reduce the stray population, there is a need for a more efficient, safe, and cost-effective solution.

New research on gene therapy may offer an alternative to surgical spaying in cats, making the process far easier and thereby hopefully reducing the number of cats and kittens looking for homes.

What Is Gene Therapy Sterilization?

A long-lasting injection that prevents ovulation in females has shown promise in recent studies, and only a single shot of this gene therapy could prevent females from falling pregnant for at least 2 years. While the initial study was very small—only six cats received the injection—only the three “control” cats that did not receive the injection could get pregnant in the 2 years the study was conducted.

The contraceptive therapy studied was the anti-Müllerian hormone (AMH), which interferes with follicle development and ovulation. Scientists first studied AMH as a way to protect ovaries in women going through chemotherapy—and this research led to the study’s authors discovering that raising the level of AMH beyond a certain level suppressed the growth of ovarian follicles. This, in turn, prevented ovulation and conception.

The treated cats were monitored for over 3 years to assess the safety of the therapy, including physical exams, ultrasounds, and bloodwork. No adverse effects were observed in any of the cats involved, which suggested that at the doses administered, the therapy was safe. Estrogen levels did not seem to be affected, and no other adverse effects were seen.

The researchers caution that more studies are required to confirm the findings before surgery is no longer the only option for sterilization. Also, the infrastructure required to produce enough shots to sterilize millions of cats is not yet available, but the study is still promising.

What Do Veterinarians Think About AMH?

Dr. Maja Platisa (DVM MRCVS) in-house veterinarian at Excitedcats.com, says there are other potential benefits to the therapy.

“AMH therapy may be able to suppress actual estrus or heat behavior in some of the females. The study population was quite small, but it’s promising to see that four out of six treated cats refused to mate with a male, while the other two that did engage in mating did not get pregnant. This may also mean less heat-related behavior in both male and female cats, which many people dislike dealing with and has given cats a bad reputation.”

In-house excitedcats.com veterinarian Dr. Lorna Whittemore (BVMS, GPcertFelp, MRCVS) is positive about the treatment too.

“The study and development of alternatives to surgical procedures are greatly welcomed. The more options we have for caring for cats, whether they are under the guardianship of human caregivers or in feral colonies, the better able we will be to find safe, effective, and ethical treatments for them. Preventing uncontrolled and unplanned pregnancies will improve the quality of life for many cats.”

Because gene therapy can last for a lifetime in other animals, including humans, it’s likely that with proper dosing, the same could be true for cats—an exciting prospect for pet owners around the world.