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What You Must Know Before Your Dog's First Heat

What you must know about your dog's first heat

Do you have a female dog that has not been desexed yet? If yes, then being aware of the signs of heat is very important for both male and female dog owners. Insights about the signs of dogs on heat can help you:
  • Be prepared for your dog’s heat;
  • Prevent unwanted litters;
  • Plan for puppies if you are a registered breeder;
  • Avoid dangerous situations with unpredictable behaviour; and
  • Provide your dog with the best care.

What is heat?

Heat is essentially your dog’s period, but it is a little different to the human menstrual cycle. For dogs, it is called the Canine Estrous Cycle. It’s made up of 4 different stages which we will outline in this blog. Your dog’s heat will occur once they have reached sexual maturity. Most people will describe heat, as the time when their female dog is passing bloody discharge from her vulva, however your dog can still be fertile and “on heat” once the bleeding has passed.  Heat usually lasts between 2 to 4 weeks; this will be further explored in the four stages of heat section in this blog.

What age does it happen?

From around 6 months of age, through the rest of her life, your dog will experience heat if she is not desexed. The age at which your dog experiences her first heat will be dependent on her breed. Smaller toy breeds reach sexual maturity and start their heat cycle from as early as 4 months of age, whereas large and giant breeds can be 2 years of age at the time they will have their first heat. It is most common that your dog will have her first heat between 6 and 15 months of age.

Dundies Heat Clipboard

How do I know if my dog is on heat?

You can sometimes work out if your female dog is coming into heat through various signs. The more aware you are of your dog’s cycle, the more prepared you can be to help care for her needs. This can include:

The vulva, near your dog’s tail, can become engorged and swollen. This is not always obvious.

Bloody discharge
This can vary in volume from dog to dog, and even between cycles with the same pet. The discharge your dog passes during her heat cycle will change as her cycle progresses. Initially It may appear very bloody, but as time passes, it will thin and become a watery pinkish red colour.
Marking and Frequent Urination
You might notice your dog having more bathroom breaks and urinating more during her heat cycle. You may even notice her marking, leaving small amounts of urine in various places in the yard or on a walk. This is normal. During this phase of your dog’s cycle, her urine contains more hormones and pheromones which she uses to indicated to other dogs that she is fertile.


You might notice your female dog excessively licking her genital area. This can indicate that she is cleaning herself and is in heat.

Behaviour Changes

You may notice your female dog’s behaviour change just before and while she is in heat. She may appear more agitated, nervous or aggressive during her heat cycle. You might also note mounting and receptive behaviour changes towards male dogs.

Tail Position

Your dog will hold her tail in different positions during the stages of her cycle.

What are the 4 stages of heat?

During the heat cycle your dog will experience four phases. Each stage is accompanied by different changes in her body and behaviour and they are as follows:
Bleeding and swelling of the vulva.
The proestrus stage of the heat cycle is where your dog’s body is preparing to mate, she may be clingier to you during this time and also more aggressive towards male dogs. You may notice your dog holding her tail close to her body during this stage.
Your dog is fertile and ready to mate.
The estrus stage of the heat cycle is where you may notice your female dog becomes more receptive to males, this is because she is fertile and ready to mate. During this phase of her cycle, she may still be having lighter bleeding and discharge which is often a straw colour.  You may notice your dog holding her tail to the side and approaching males. She may also be more aggressive to other female dogs during this stage.
Your dog may be pregnant or no longer fertile.
The diestrus stage occurs right after the proestrus and estrus or “in heat” stages of your dog’s cycle. If not pregnant her vulvar swelling will decrease and discharge disappear.  If she has been mated, then during this time she may develop into pregnancy. 
The dog is getting ready for their next cycle.
The anestrus stage is like the body’s standby mode. This is the inactive phase of your dog’s cycle where she doesn’t experience any hormonal or sexual behaviour changes.

Dog Heat Cycle

How do I know when my dog has finished heat?

When your dog enters the Diestrus phase she has finished heat. Her behaviour should return to normal, discharge subsite and sewing of her genitals will go down. This is usually 2-3 weeks after you have noticed the last of her bloody discharge. 

How often will my dog go into heat?

Dogs will experience heat, on average, every 6 months. It can take up to 12 months for your dog’s heat cycle to become regular.
Smaller breeds can experience heat more frequently, having up to 4 heat cycles per year. Larger and giant breeds may experience heat even less having only once cycle every 12 to 18 months. Unless desexed, your female dog will never stop having heat cycles, however the time between heat cycle will become further and further apart as your pet ages.
There is no link to indicate a breeding season for domestic dogs, so your dog may go into heat during summer, autumn, winter or spring. There are only 2 domesticated dog breeds with cycles that correspond to season, these are the Tibetan Mastiff and Basenji who typically only cycle in Spring.

How soon after my dog has finished her heat cycle, can she be desexed?

When your dog is in heat, there is an increased blood flow to both the uterus and ovaries. Dogs can be desexed while they are on heat, but there is an increase risk for bleeding. Most vets will recommend waiting 8 weeks after your dog has finished bleeding before they are desexed.

Dog Cleaning Vulva

How Can I manage it & care for my dog?

Heat can be messy and lengthy, and overall, not too fun. These are some simple tips and tricks to keep your fur baby comfortable and clean.
Invest in a good pet nappy
Finding a quality pet nappy can help you kept your dog and home clean while she is in heat. You can keep her close without the stress of mess. The Dundies Snappie is a great option – you can read more about choosing the right dog nappy here.
Comfy Bedding and Blankets
Dogs can get a little more sensitive when they are on heat, providing a special blanket or bed for her can help her feel more comfortable. It also keeps mess contained to one easy clean area if you choose not to use a pet nappy.
Keep Wipes on Hand
Heat can be messy, having a packet of baby wipes on hand ready to go can help keep your home clean.
Extra Cuddles
Some dogs can get quite snuggly during their heat cycle, so make sure to make time for extra cuddles. Also make sure you dog has plenty of access to fresh clean water.
Chew Toys or Soft Toys

Providing some extra mental stimulation and security with toys can help to keep your pet feeling calm.

Don’t Scold
If your dog does make a mess with blood, it was not intentional. She may already be stressed if she is waking up and finding herself in a messy state, scolding her will just add extra stress. Rather provide comfort and cuddles while you clean.

dog on heat

How can I keep my dog safe?

When your dog experiences her first heat cycle, it can be a nerve-racking experience. These are some things you can do as a responsible owner to care for your female dog in heat.  
Supervise your dog at all times
Never let your dog outside alone during heat. Male dogs who smell your female dogs’ pheromones can come from far and wide to mate, don’t underestimate their determination. If you do, you may end up coming home from getting groceries to find the male dog from around the block has climbed your six-foot fence and is mating with your girl.
Avoid off leash play areas
Avoid dog parks and off leash play areas when your dog is in heat. Even if your dog has excellent recall, she may find herself influenced by her hormones if she is intent on finding a male dog to mate with. Sticking to an on leash walk in an area you are confident in taking her would be the better option for exercise.
Microchips and ID
We never want our pets to get lost, but if there is a time when they are more prone to wander, it will be during “heat.” Make sure their microchip details are up to date and that she is wearing a collar with your details easily accessible if the unthinkable happens.
Keep an eye on her health
Sometimes health issues can arise for your dog. After the heat cycle when the uterine lining remains thickened in preparation for pregnancy, it can produce more fluid creating an ideal environment for bacteria to grow. This can cause pyometra, a uterine infection. This can be life threatening. Keep an eye out for excessive drinking, decreased appetite, return of discharge or bleeding, lethargy and or fever. If you suspect any of these symptoms, please seek the advice of your veterinarian immediately.
If you are not a registered breeder or your dog doesn’t need to remain entire for purposes such as showing, why not consider desexing your pet! Your vet will be able to provide guidance as to the ideal age and time to perform a desexing surgery for your dog.

dogs in lust

Recommended Products

Keeping our pets clean and comfy while they are on heat is made easier with these fantastic Dundies recommended products:
ID Pet Tags and Collar – Pupstyle Logo ID Tag & Collar
Nappies – The Dundies Snappie
Bed Covers – The Dundies Puppy Pad
Cosy Bed – Indie Boho Pet Bed with washable cover
Fun Toys – Furry and Fabulous Toys, Puzzles and Feeders.

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