What to expect when your dog comes into heat

What to expect when your dog comes into heat

If you have a female dog who hasn’t been spayed, you may have questions about what to expect when she comes into heat. From recognizing the signs and understanding how long a heat cycle lasts to preventing an unplanned pregnancy and keeping her comfortable, knowing what to expect can help you and your dog navigate the experience.

How will I know my dog is in heat and how long will her heat last?

The first signs a dog is going into heat are swelling around her vulva and bloody vaginal discharge. You will know your dog’s heat is coming to an end when her vulva is back to its normal size and you no longer see any vaginal discharge. When your dog does come into heat, you can expect her heat cycle to last somewhere between two and three weeks.

When will my female dog first come into heat?

Sexual maturity for the female dog usually happens around six months of age. Smaller breeds may go into heat earlier than this. Large breed dogs can be up to two years old before they start their first one.

How often will my female dog come into heat?

Female dogs typically come into heat about twice a year, but this is an average. When your dog first starts cycling, the timing between her heats may be irregular. Heats generally become more regular after about a year.

I do not want my dog coming into heat and getting pregnant. What can be done to prevent this?

The recommended way to prevent heat and unplanned pregnancy is to have your dog spayed. This surgical procedure is performed by a veterinarian while your dog is under general anesthesia. At the Ontario SPCA and Humane Society’s high-quality, high-volume spay/neuter clinics, we surgically remove both ovaries as well as the uterus. This is called an ovariohysterectomy. This procedure is irreversible. Your dog will no longer go into heat and will not be able to become pregnant. Spaying also reduces your dog’s risk of certain diseases and may help prevent behavioural issues.

Learn more about our veterinary services.

Hormonal therapy may be used to suppress your dog’s cycle, but this is only temporary and not often recommended due to the potential for serious adverse effects.

My dog has come into heat. What should I do?

If your female dog comes into heat before you can get her spayed, here is what you can do:

First, mark down on your calendar the date your dog starts her heat and the date she ends her heat.

Next, when calling to book your dog’s surgery, please tell the veterinary clinic the dates that you marked on your calendar. It is very important that your dog is booked for surgery no earlier than eight weeks from the beginning of her last heat. This waiting time is necessary for your dog’s safety to minimize blood loss during surgery.

Please remember that when a female dog is in heat, she will be receptive to male dogs. In addition, they will be very interested in her! It’s at this time that she may allow mating. Keep your dog on a leash at all times and consider going for walks where you do not expect to meet other dogs. Allowing her out in your backyard unsupervised could also draw unplanned attention from the male dogs in your area, so supervised outdoor time is advised.

Managing the flow

Some female dogs have bloody discharge during heat, while others may have very little. Doggy diapers or washable, waterproof sanitary pants can help manage the discharge and protect your home. If using sanitary pants, you can add a sanitary pad for additional absorbency. Diapers or sanitary pants and pads should be changed regularly and may need to be changed three or more times a day, depending on your dog’s flow.

Allow your dog some supervised time outside without the diaper so her skin can breathe. Also, give any soiled areas on her hind end a gentle clean with warm water and a cloth once a day and then towel dry. This should help to minimize skin irritation. Diapers and pants are only recommended if your dog won’t ingest them, which can lead to other complications.

Book a spay appointment

To learn more about our spay and neuter services, visit ontariospca.ca/spayneuter.

If this information was helpful, please help us continue to educate about pet health and well-being by making a donation. As a registered charity that does not receive annual government funding, the Ontario SPCA and Humane Society depends on the generosity of donors to change the lives of animals in need.