Staying Healthy

Stages of the Heat Cycle of a Dog (or, Why You Should Spay Early)

“This post contains affiliate links, and I will be compensated if you make a purchase after clicking on my links.”

Dog breeders are very astute when determining the stages of the heat cycle a female dog is in, but for the rest of us this can be somewhat of a mystery. Let me say first if you own a female dog and do not intend to have her bred, then do the right thing and have her spayed when she reaches the proper age. This age will vary according to breed so always check with your vet about when to schedule her for this procedure.

Contrary to popular opinion, it is considered best to spay before the first heat cycle if you do not intend to breed the dog. As explained on the website:

…current research does show that spaying before the first heat prevents the development of mammary gland tumors. Since females can go into heat as young as four months of age, they should be spayed before then to receive that protection.

Stages of the Heat Cycle

First stage of the heat cycle is called Proestrus. Male dogs will become very interested in the dog, and she will begin to bleed from the vulva and the vulva will swell.

Next stage is the Estrus stage. She is ready to be bred during this time of 4 to 21 days in length. A female dog in stage two is not selective about what breed of male dog mates with her, so during this period keep her away from all but the breed you wish her to breed with.

Third of the stages of the heat cycle is known as the Diestrus stage. This is when she is entering the end of her heat cycle. This lasts roughly 7 days although various breeds go through this stage ranging from 4 to 14 days.

Your female dog will again enter the heat cycle normally seven months later and every seven months after that, and this will be her normal time frame. This is true even if she became pregnant and has had a litter of puppies.

Look for these indications as a tip off she is entering her cycle. She will begin to lick the vulva, bleeding from the vagina, the amount of bleeding is heavy for the first few days and then slowly decreases as she is progressing in the heat cycle. The color of the blood will be a dark red at first and gradually change to a much lighter color, her vulva swells, and she will begin to urinate frequently while her tail will lay over from side to side.

During these stages of the heat cycle it is vital to keep the dog confined if you are not wanting her bred. This means no walks, romps in the park, etc.

And, remember what the ASPCA quoted article above had to say: spay early, and you may quite possibly save your dog’s life. Do you routinely spay/neuter your dogs early?

Image 100572046 13348155


  1. The article doesn’t say to spay ASAP, it says to spay before the first heat cycle. In some breeds, this happens as late as 8 or 9 months. I have a Golden Retriever who was spayed at 7.5 months – as late as possible, but before the first heat cycle. There are benefits to spaying before the heat cycle as well as benefits to spaying after – the point is to check with your veterinarian and choose the best course of action based on your breed and your pet’s health and medical history. As with any major medical procedure, you have to weigh the pros and cons. As for spaying, there are pros and cons to both doing it early and to waiting. For many, the benefits to spaying before the first heat cycle (minimizing certain cancer risks for example) outweigh the benefits to waiting until after.

  2. Avatar Of Wilma Snyder

    Wilma Snyder


    Kris Z is so right !! I am surprised at this site spinning out the old science. Keep up with modern findings and new science if you are going to be a source of education for people. Give them the facts and let then decide for themselves.
    If you can’t keep your pet intact and not keep it from getting pregnant/or getting one pregnant, perhaps you have no business owning a pet at all.

  3. Avatar Of Kris Z

    kris z


    wrong.. early spaying causes issues that everyone conveniently didn’t mention. like urine leakage, which mine 2 yr old has. she was spayed at 4 months and leaks. she also has a fold in her vagina that causes urine to stay on her and causes her to have infections. also she grew talle than she would have. i would never get a female spayed prior to one year old ever again. ever. if you are too incompetent to keep your dog inside and out of harms way thru the heat cycles then at least wait until 6 months old but even that is too young.

    • Avatar Of Beth



      AGREED!!! Disappointed in Dogington Post again for not thoroughly researching the topic. I have the same issues with my female as you’ve listed Kris Z. as I was misled and told to have her spayed before first heat.

Leave a Reply

Your email address will not be published. Required fields are marked *

To Top

Like Us for Wonderful Dog Stories and Cute Photos!