Last Updated: 08/04/2026
Dogs on Heat: A Vet's Guide to Signs and Care
From managing discharge with doggy nappies to understanding hormonal changes and preventing pregnancy, our expert vet guide explains everything you need to know about the heat cycle to keep your dog comfortable and safe.
Author: Dr Chelsi Kuebler BVSc
Reading Time: 6 minutes - short read
Noticing that your female dog is acting a little restless or seeing those first spots of blood on the rug can be a bit daunting for any pet parent. Being "on heat" or "in season" is a completely natural part of a female dog’s life, signaling the oestrus phase of her reproductive cycle. While it brings about some hormonal shifts and physical changes, it also requires a little extra vigilance to keep her comfortable and prevent an unplanned litter. Understanding the timing, symptoms, and care requirements of a heat cycle is essential for any pet parent with an undesexed female.
Understanding the Heat Cycle in Dogs
When Do Dogs Go on Heat?
The average age of sexual maturity in dogs is 6 months. However this can vary based on breed and genetics. Some smaller breed dogs can go into heat as early as 4 months of age, whereas large breed dogs tend to mature later and may not have their first heat until they are over 18 months old!
How Often Do Dogs Go on Heat?
The frequency of "heats" or "seasons" also depends on breed size. Small breed dogs can go in heat 3-4 times a year, whereas giant breeds may only go on heat once a year.
How Long Do Dogs Stay on Heat?
Most heat cycles last anywhere from 1.5 to 4 weeks. Although your dog may not be displaying heat behaviours, she can fall pregnant anywhere during this time frame. Therefore it is important to keep her isolated from other dogs (males especially) to avoid mating and any unusual behaviours from other females. You will know when her cycle is over when there is no longer any discharge, and her vulva goes back down to a normal size.
Signs of a Dog on Heat
The signs of heat in dogs can vary from dog to dog, but they will generally include:
- The earliest symptom of heat is a swollen vulva, though because this symptom may not be all that obvious, many owners don't realise their dog is on heat until she starts vaginal bleeding.
- The vaginal discharge can change in consistency and colour throughout the cycle. This is normal. However, if the discharge is white/cream coloured with a bad odour, this could be a sign of infection and she will need to be seen by a vet.
- Because of the discharge and swelling, your dog may lick her genitals more than usual.
- Female dogs on heat often urinate more often and may exhibit "marking" behaviours on walks - urinating small amounts frequently. Their urine has pheromones in it that can attract a mate.
- Female dogs on heat can be more friendly with other dogs than usual and often display humping/mounting behaviours.
- When touched around her hips she may stand up or move her tail to the side.
- Dogs in heat can also become quite restless at home and display nesting behaviours, such as burrowing in their blankets/bedding.
How Can I Care for my Dog While She's on Heat?
While heat cycles are a natural part of caring for an undesexed female dog, there are a few things you can do to ensure both you and your dog are set up for success.
- To assist in the nesting and restless behaviours, you can provide distractions such as puzzle toys, or distract her by taking her on a walk.
- To help keep her (and your furniture) clean from vaginal discharge, you can invest in some wipes and doggy diapers.
- Ensure her collar and tags are intact and legible and that her microchip details are up to date. If the worst happens and she gets out to find a mate, at least she will be able to be traced back to you.
- Contact your vet if your pet is acting unwell. After heat cycles there can be leftover inflammation and swelling, which can sometimes result in bacterial growth. Your vet will be able to determine if your pet has an infection and how to treat it.
- Give her lots of cuddles and attention!
How Do I Keep my Dog from Getting Pregnant?
The best and easiest way to prevent pregnancy in dogs is to get your dog desexed. Your local vet should offer this procedure. It is a routine surgery and in most cases is easy to do and with little risk.
However, if your vet has recommended waiting to have your dog desexed, maybe because she is a large breed, the best way to avoid becoming an unwanted pet-grandparent is to make sure your in-heat female dog isn't mated. As stated above, keep her isolated from other dogs while she is on heat. This means avoiding dog hotels, doggy daycare, dog parks, and the beach. Stay clear of other dogs while on walks. It is also a good idea to avoid leaving her outside unsupervised as male dogs can be quite determined and figure out a way into the yard.
If there has been an accidental mating, contact your vet immediately. You can book your dog in for an injection that will terminate the pregnancy.
Navigating a dog's heat cycle doesn't have to be a stressful experience. By staying observant of her symptoms and providing a little extra TLC - along with some practical tools like puzzle toys and hygiene wipes - you can help her feel secure and settled. Remember, the most effective way to manage reproductive health and prevent accidental pregnancy long-term is desexing. If you notice any unusual discharge or if your pet seems unwell during her season, always reach out to your veterinarian for a check-up to ensure she stays in tip-top shape.
Dog Oestrus FAQs
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History
Our experts continually monitor the health and wellness space and we update our articles when new information becomes available.
Thu 9 Apr 2026
Edited by Dr Belinda Stancombe BVSc (Hons)Dr Chelsi Kuebler BVSc
Contributing Author, BVSc
From a very young age I knew I wanted to help animals. As I grew up I considered other career paths but always circled back to my dream of becoming a vet. I’m from Minnesota originally but I came to Australia for vet school and graduated from the University of Sydney in 2019. Since graduating I have worked in both small animal and mixed practice. We have 2 pets – a dog and a cat. Ahsoka is our blonde Kelpie mix and Binx is our charcoal tabby Domestic Shorthair.
