There’s no denying it—your puppy is growing up. Every day she looks less like a puppy and more like a gangly teenager. And with these outer changes happening, another important inner change is also starting to take place: puberty.
We know it may seem really early to talk about the birds and the bees, but puppies grow much faster than people and reach reproductive maturity surprisingly quickly.
The average dog has their first estrus, known as heat, at 6 months old. Small-breed dogs may have their first heat as early as 5 months of age while large dogs may not have their first estrus until they are 7 or 8 months old. Giant-breed dogs can be late bloomers, so you may not see a heat until they’re anywhere from 12 to 18 months old.
If you haven’t yet, you may see your puppy go through a heat cycle soon. Here’s what you can expect.
Physical changes
The classic changes that mark a heat cycle are a swollen vulva and vaginal bleeding. Don’t be alarmed if you see this—your puppy isn’t in pain! She is simply experiencing natural changes to her uterus to prepare her for a possible pregnancy. The amount of bleeding and how long the cycle lasts can vary by dog. In most dogs, bleeding lasts 1 to 3 weeks. You can purchase dog diapers to help reduce the mess, and you should keep your dog in rooms with floors that are easily cleaned.
One quick note: The bleeding your dog experiences in a heat cycle is not the same as what a human with a uterus might experience during a period. Your female dog isn’t bleeding from shedding the inner lining of her uterus. The bleeding a dog experiences is due to the effects of the hormone estrogen.
You can sometimes also see some swelling along your dog’s mammary glands. This means you might notice some thickened tissue under her nipples.
Behavioral changes
During heat, your dog may be more nervous or alert. She’ll also be more receptive to male dogs mounting her and may even present herself to male dogs. You might notice that she’s peeing more often and marking around the house and yard. Her pee contains pheromones that will attract intact (unneutered) male dogs.
It’s amazing what these unneutered male dogs will do to get to a female dog. Don’t assume that because your puppy is confined in a yard with a fence, she will not get pregnant—after all, fences can be jumped or dug under. To prevent unwanted pregnancy, supervise your puppy every time she goes outside until her bleeding ends.
If all of this sounds like a lot of mess and work, the good news is that heat cycles don’t happen often in dogs. Your puppy’s first few heat cycles may be irregular, but as an adult, you can expect 2 cycles per year for most dogs. Some small dogs may cycle up to 3 times per year while some giant-breed dogs may only cycle once per year.
If you’re planning to breed your pet, it’s best not to do it on this first heat cycle. Your puppy is still young and has a lot of growing to do. Pregnancy can have many complications, so it’s best to let your puppy mature a bit first.
Speak with your veterinarian about when it is best to get your puppy spayed. Aside from the mess and potential unwanted pregnancy, leaving your puppy intact also increases her chances of life-threatening diseases, such as pyometra (infection of the uterus) and mammary (breast) cancer. Depending on your puppy’s size, she may benefit from growing up more before her spay procedure. Your VCA care team will be happy to work with you to help you determine the appropriate time to spay your puppy.
A spay procedure can be added on to a CareClub® membership. Annual exams, rechecks and sick appointments1 are all included along with the vaccines and yearly preventive services2 your pet needs to support their best health.
CareClub Memberships are preventive pet health care plans and not pet insurance. CareClub Membership covers only the selected health care services and products which are specifically identified in the applicable CareClub Membership agreement.
1. Covered services vary by CareClub plan. Unlimited exams are any exams during regular business hours, excluding specialty, emergency and telemedicine exams. Urgent care exams are available through CareClub until December 31, 2024, at select VCA Animal Hospitals Urgent Care locations.
2. Vaccines may include rabies, distemper, parvovirus, canine upper respiratory disease, canine influenza, leptospirosis and Lyme disease, depending on your location. Lab work checks for issues like diabetes, liver and kidney disease, parasites and general infections.
