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By Dr. Sara Ochoa – Practicing Veterinarian

If you have a female dog, they may have just started going into heat and having a period. At first, you may think there is something wrong with your dog after noticing bloody discharge from their vulva.

Most of the time, this is normal and will go away after a few days to a week. If your dog is not spayed, this article is everything you need to know about your dog’s period and when you need to see your vet.

Do dogs have periods? 

Yes, female dogs have periods, unless they are spayed. Dog periods are different from human periods, however. Whilst humans shed their uterus lining, dogs absorb it if they have not been impregnated. This is called a heat cycle.

Like humans, dog periods are affected by hormones produced by the ovaries. These hormones are responsible for getting the uterus ready for pregnancy. This process requires the uterus to be supplied with extra blood in preparation for breeding. 

This causes the blood that you see during their heat cycle. 

As long as your dog is not spayed, they will have a heat cycle and a period.

In women, bloody discharge signifies the end of a reproductive cycle, whereas in dogs, bloody discharge indicates the dog is fertile and ready to breed.

Male dogs do not have periods.

When do dog periods start? 

Your female dog will first have a period when she is about 6 months of age. Many times, their first period may be missed since it is a very small amount of bleeding, and most dogs like to be very clean and will constantly lick themselves to keep themselves clean.

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Smaller dogs may have their first heat cycle earlier in life, 5-6 months in some cases, whereas large breed dogs may start having their first period around 8 months of age, and even up to 1-2 years.

If you’re wondering what to do when you dog has their period, then be sure to read our post about that subject by clicking on the link.

How long do dog periods last? 

Most dog’s periods will last about 7 to 10 days. This would be when you visibly see them bleeding. Their whole heat cycle will last 2 to 4 weeks where they are undergoing hormonal changes and are accepting a male to mate. 

What does a typical heat cycle in a dog look like?

Your dog will first start their cycle with their vulva starting to swell. After this, you will notice a little bit of bloody discharge from their vulva. Many times this starts a few days after they first start their cycle.

Your dog may have heavy bleeding at first, and it will start to slow down as their cycle comes to an end.

During their heat cycle, you may notice that your dog is urinating a little more often.

This is how they release hormones and pheromones to signal to a male dog that they are in heat and ready to be bred.

Most female dogs will start allowing male dogs to breed them around 7 to 10 days into their cycle.

Your dog will be done with their heat cycle when you no longer see any blood and their vulva is no longer swollen.

If your dog is bleeding too much, or their swollen vulva is larger than what is considered normal during their heat cycle, then be sure to read our post Dog in Heat: Problems and Help.

How often do dogs get their period?

Most dogs will have a period every 6 months. They can be as long as 8 to 10 months between periods, and they can be as short as 3 months between periods. Most dogs will be very consistent on their time between each period.

How does my vet tell if my dog is in heat?

There are two different tests that your vet can run to see if your dog is in heat and ready to mate.

  1. Vaginal cytology:

Your vet can take a swab of your dog’s vulva with a cotton tip applicator. They can smear this swab on a glass slide and look at it under the microscope.

During your dog’s heat cycle, the cells that line the vulva will change in appearance. Your vet will easily be able to tell you if your dog is in heat and ready to be bred.

  1. Blood testing:

A progesterone test can also be used to determine if your dog is in heat. This test may be able to be performed at your vet clinic, or it may have to be sent off the lab for the most accurate results.

If you are trying to breed your dog, your vet can work with you on determining the most accurate time to breed your dog.

Do dogs get period cramps?

No, it is unlikely that dogs get period cramps during their heat cycle. Dogs do not shed their uterus lining as humans do, however, absorb their lining back into their body. It’s possible that there is discomfort associated with this process, however, it’s more probably discomfort comes from hormonal changes.

The process of reabsorbing their uterus lining is referred to as covert menstruation. Allowing your dog to rest and not go on any long walks will help them to be more comfortable during this time.

Do spayed dogs have periods? 

If your dog is spayed, they should not have a period. There is one instance where they will have a period. If your dog has any ovary tissue left from their spay, they can still have a period, but they cannot get pregnant during this time.

Ovarian remanent syndrome is when a piece of the ovary was left during your dog’s spay, causing them to still have signs that they are in heat.

If your dog is still having a period after they have been spayed, it would be best for your vet to run bloodwork to see if they have an ovarian remanent syndrome or something else is causing them to bleed.

If your dog does have an ovarian remanent syndrome, this can easily be corrected by surgically removing the rest of the ovarian tissue.

Your dog would need to have this procedure done when they are in heat so that it is easier to find the ovarian tissue.

Do dogs have periods every month?

No, dogs do not have a period every month. They only have their periods a few times each year. Small dogs tend to have a period and go into heat every 3 to 4 months. Other dogs, it can take up to 18 to 24 months for them to have their next cycle.

Do dog periods get shorter with age?

As your dog gets older, their periods will become shorter and less frequent. Your dog will eventually go through menopause and stop having periods.

This usually occurs around 10 to 12 years of age. Some dogs will have periods their whole life, and some dogs may only have one or two periods during their lifetime.

If you notice anything different with your dog’s period or it seems like they are happening very often, it’s best that your vet checks your dog to make sure that there is nothing wrong.

Do dog periods smell?

Your dog’s period may have a little odor to them, but they should not be very smelly. If your dog is having blood discharge from their vulva that is very smelly, it would be best to see your vet. This could be a sign of a pyometra.

A pyometra is an infection in your dog’s uterus. This usually occurs shortly after your dog is in heat.

The hormonal and physical changes that happen when your dog is in heat can cause your dog’s uterus to get infected. This uterus can fill with pus causing your dog to have a creamy, bloody discharge.

If your dog does have a pyometra, your vet will want to do emergency surgery to remove the uterus and the infection.

If left untreated, this infection can cause the uterus to rupture, allowing the pus to enter your dog’s abdomen and bloodstream. Your dog could then become septic and die.

When would I need to see my vet?

Many times, if your dog is having a period, you will not need to see your vet. If you notice anything abnormal with their period, it may be time to see your vet.

Some dogs may have a urinary tract infection and are urinating blood, but it looks like they are in heat.

If you notice that your dog is producing a very large amount of blood, it is always best for your vet to check them out just to make sure that there is nothing else wrong.

Final Thoughts

If your dog is not spayed, you can expect them to come into heat about every 6 months starting when they are 6 to 8 months old.

Many people do not want to have to deal with the bleeding, clean up and mess that can be associated with a heat cycle. This is one reason that many people spay their dogs.

A spayed dog will not have a period as these cycles are caused by hormones released by the ovaries.

If your dog is bleeding from the vulva and they are spayed, or they should not be having their heat cycle, it is best to see your vet.

There are a few medical issues that can cause your dog to seem like they have a period that may be life-threatening if left untreated.

Periods can be a challenge to deal with at first but learning everything that you can about your dog’s heat cycle will help you to recognize any changes in your dog and when you should seek the advice of your veterinarian.