A birth control pill... for dogs?

Scientists are developing a chemical means of curbing the unwanted consequences of puppy love

A dog feeds its 15 puppies in China in 2009: Researchers are working on a contraceptive drug for dogs that would replace the need to spay females.
(Image credit: Xu Changzheng/CORBIS)

It's nearly universally agreed upon that spaying or neutering your dog is a responsible part of pet ownership. But those surgical procedures are costly, and require pets to be put under anesthesia, which always bears some risk. To make controlling the pet population easier and cheaper, scientists in Arizona are developing a contraceptive for female dogs that can be administered orally or by injection. Here, a brief guide:

There's birth control for dogs?

It's in the works. Along with SenesTech, a biotech company that specializes in "humane animal population management," Arizona scientist Dr. Loretta Mayer has developed Chemspay, a doggy contraceptive that is administered once orally or via injection, and induces menopause in an animal. In trials conducted between 2004 and 2008, the drug significantly reduced the number of eggs in test dogs, thus rendering them unable to have puppies.

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What's next for this canine pill?

Mayer is taking her research to India, where she's working on a project to curb the country's feral dog population. "This technology, if successful, will really have a huge impact on unwanted dog populations," she says. "The biggest impact will be where dogs are reservoirs for human diseases, like in India." Stateside, it could dramatically decrease the number of unwanted dogs that are euthanized, says Maria Parece at Gather.

So when can American dogs get in on this?

In three years or so, Mayer plans to begin FDA trials at an animal rescue center in Flagstaff, Ariz. It will take a total of six to nine years for Chemspay to gain FDA approval. "There is a very long timeline in this project," Mayer says. "Each and every one of our products takes years to develop."

Has man's best friend had contraceptive options before?

Yes. For male dogs, there was a sterilizing injection called Neutersol. It gained FDA approval in 2003, but was taken off the market in 2005 following manufacturing issues. It is now commercially available under the name Esterilsol in Mexico, Colombia, and Bolivia. It also has regulatory approval in Panama, and its makers hope to gain approval throughout Latin America. Studies are also reportedly underway to try using GonaCon, a contraceptive used to control deer populations, in dogs.

Are there any disadvantages to these products?

For Chemspay, time — and FDA trials — will tell. But Neutersol/Esterilsol doesn't completely shut down testosterone production, leaving male dogs more vulnerable to testicular cancer and prostate disease than those who have their testicles surgically removed.

Are there other birth control options for animals?

Yes. Mayer and SenesTech are also developing ContraPest, a drug that sterilizes female mice and rats, known to terrorize Indonesia's rice fields and wreak havoc on the food supply. The drug is thought of as a more humane alternative to poisoning rodents. "I would really like to see us do things that improve our environment and are compassionate to other beings," Mayer says. "My passion, without question, is to stop killing animals, however we might do that."

Sources: Alliance for Contraception in Cats & Dogs, Gather, Humane Society of the United States, SenesTech, USA Today

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