- Not a substitute for professional veterinary help.
For humans, menopause is when people with periods stop having monthly periods and are far less likely to have children. You’d be forgiven for thinking that if female dogs also regularly menstruate and go “into heat” in preparation for pregnancy, they may eventually go through menopause too. But this isn’t the case.
Dogs do not go through a human-like process of menopause. Instead of a hard stop to their periods, older unspayed dogs will continue to have periods of ‘being in heat’ — when she can get pregnant — once or twice a year throughout her entire life.
Because there is no age where dogs stop going into heat, it’s important to understand the health impacts of a heat cycle, and what happens if you choose to spay, or not spay, your dog.
What If My Dog’s Heat Cycle Has Stopped?
Unspayed dogs’ heat cycles become longer as they age but never stop entirely. If your dog has stopped going into heat, this can be a sign of health problems and should be checked out, says Caroline Reay, head of veterinary services at UK national pet charity Blue Cross. A lack of periods and far less frequent ovulation is not the same as transitioning into menopause.
That said, Dr. Sarah Wooten, DVM and Pumpkin Pet Insurance veterinary expert, shares that spayed dogs are technically in menopause because their ovaries are removed, and they no longer have sex hormones in their body. By human definition, a spayed dog can be considered “in menopause” because they no longer have menstrual cycles.
The Importance Of Spaying as Reliable Birth Control
Spaying — when the ovaries are surgically removed — is the best way to prevent your dog from getting pregnant. Spaying’s benefits also extend well beyond avoiding surprises.
“You won’t have the mess and inconvenience of seasons,” Reay says. Seasons of when your dog is in heat may require you to change your entire routine, from what time you walk your dog to how many diapers you need on hand. “Also, roughly a quarter of [unspayed female dogs] will develop a serious womb infection in later life.”
While some TLC is necessary after the procedure, you won’t have to wait long until your dog is back on her feet. The average recovery time after a spay procedure is around two weeks. After spaying, you might also see positive behavior changes in your dog. Wooten says that generally, spaying reduces energy, urine marking, and aggression.
However, she does caution that negative behaviors can also develop after spaying, depending on the age or breed of your dog. For example, one study saw an increase in touch sensitivity, aggression, fear, and barking — although these effects appeared to be ‘highly breed-specific.’ Different researchers also noted the age at which a canine is spayed might influence negative behaviors.
How Often Do Dogs Go Into Heat?
Most dogs hit sexual maturity and start going into heat around 9 to 10 months. However, this can vary between breeds and sizes. “Smaller dogs hit puberty earlier (as early as 6 months), and large dogs later (as late as 24 months of age),” Wooten says.
The frequency of a dog’s heat cycles can also differ according to the breed. Most dogs cycle every six months, but this can range from four to eight months, Reay explains. “It’s said that Basenjis and some ‘sled dog breeds’ only come into season once a year.”
A dog can’t get pregnant when not in heat or before she reaches sexual maturity, as she won’t be ovulating.
Signs Your Dog May Be in Heat
Feel more grouchy or tired around a certain time of the month? Dogs also experience a few changes as they come into heat.
Some common signs your dog is in heat include:
- More frequent urination
- Swollen vulva and licking of genitals
- Increased interest in male dogs
- Increased vocalization
- Sideways tail movements
- Restless and mood swings
- Nesting behaviors
Another noticeable change? You may see some bleeding or bloody discharge. However, this isn’t your dog having a period.
“Dogs, in contrast, bleed around the time they are ready to mate and get pregnant, and mate while they are bleeding,” explains Wooten.
How Long Is a Heat Cycle In Dogs?
A female dog’s heat cycle, or ‘estrous cycle’, occurs in four stages: proestrus, estrus, diestrus, and anestrus. Proestrus and estrus together are typically what is referred to when a dog is in ‘season’ or ‘in heat’. This stage, where a dog’s period also occurs, can last anywhere from two to four weeks.
- Proestrus. In this first stage, a dog’s vulva swells, and she excretes thin and watery vulvar discharge that can also be bloody, says Wooten. Proestrus lasts anywhere from 3 to 17 days, and during this period, the hormones estradiol and estrogen increase.
- Estrus. On average, this stage lasts around 9 days but can vary between 3 and 21 days. Bleeding continues, and pregnancy hormones reach their peak. “During estrus, dogs ovulate — and, if they mate, the eggs are fertilized, and the dog gets pregnant,” Wooten adds.
- Diestrus. Diestrus is the luteal phase of the heat cycle after a dog ovulates, and progesterone continues to climb. If she hasn’t mated, progesterone slowly declines over two months. It is also at this time that discharge ends, and the vulva stops swelling. Wooten says you’ll know this stage has begun when a female dog refuses the ‘advances’ of a male dog.
- Anestrus. This final stage can last 4-5 months for dogs who are in heat twice a year, and it’s when the uterus repairs itself. It continues until a dog re-enters proestrus once again.
Can Dogs Get Pregnant At Any Age?
The simple answer is yes: once a dog has her first heat cycle, she can get pregnant. If you are planning on puppies, it’s best to wait until your canine reaches physical maturity (between one and two years old, depending on the breed). Hitting ‘adulthood’ is also the stage of her life when she is most fertile.
A dog’s pregnancy is much shorter than a human’s, lasting around nine weeks. And, because heat cycles continue throughout her life (unless spayed), it is technically possible for her to conceive at any age — although this is not recommended.
Wooten adds that six years of age is the typical ‘cut-off’ point for canine pregnancy. “Just like in humans, pregnancy is harder on older dogs — [they] aren’t as resilient,” she says. Furthermore, Wooten says older female dogs are at higher risk for pregnancy and uterine complications, such as dystocia (difficult birth), pyometra (life-threatening uterine infections), and uterine cancer.
“What’s considered ‘old’ varies a lot between breeds (and individuals), but generally, big dogs age faster than little ones,” Reay reveals.
Carrying a litter is also tougher on an older dog’s overall health. According to Reay, “[the] sheer weight of a pregnant uterus puts a lot more strain on body systems, like the heart and joints.”
What Other Ways Can I Prevent My Dog From Getting Pregnant?
If spaying isn’t the best route for you and your dog, other approaches can help reduce her risk of pregnancy and help your dog transition into menopause. According to Reay, these include:
- Be aware of ‘heat’ signs. Keep your female dog away from males when she’s in season. That includes related males, as siblings and even parents will want to breed.
- Keep her on a leash when outdoors. Do so at all times, and be aware that male dogs will be interested and persistent.
- Change your routine so you encounter fewer dogs. This may look like early morning or late night walks to avoid running into intact male dogs.
- Use ‘birth control’ drugs. There are drugs that can prevent heat and also drugs that can be used for abortion if your female dog gets pregnant. These include dexamethasone and prostaglandin.
An unplanned pregnancy can be costly and potentially affect your dog’s well-being, so it’s best to stay clued up and keep an eye on your dog’s cycles. And don’t forget: discussing any concerns with your vet is the optimal approach to making informed decisions and ensuring your dog stays happy and healthy.