Most dogs get their first heat when they are about 6 months of age.
When this happens to you for the first time, it can feel quite daunting and one of your biggest concerns might be an unwanted pregnancy.
While in heat, female dogs produce a bloody discharge similar to human menstruation.
Unfortunately, most aspects of the dog’s heat cycle aren’t like a period at all so this won’t help us when it comes to canine fertility.
A dog’s cycle is divided into 4 stages and only during one of them can a dog get pregnant.
I have compiled the most important points when it comes to dog heat, what you need to pay attention to, and how you can spot those fertile days.
Important: Do NOT rely on timing the fertile days of your female. Instead, supervise her and keep her on a leash from the day you suspect her heat has started and well beyond when the bleeding has stopped.
When Can a Dog Get Pregnant During Heat?
A dog is most likely to get pregnant during the estrus stage of their heat cycle which may begin nine days after the heat has started and can last about nine days.
The reproductive cycle (estrous) of a female dog is made up of four different stages.
These are called proestrus, estrus, diestrus, and anestrus and each comes with different symptoms.
Proestrus starts with the swelling of the vulva which is one of the first signs that your dog is going into heat.
Bleeding usually follows quickly and the amount varies for each individual dog.
Some canines can bleed quite heavily while others rarely leave drops on the floor.
Take a look at my article to find out how much blood is normal for a dog in heat.
A dog’s cycle can look very different from dog to dog so the proestrus stage can last anywhere from 3 to 17 days.
Some dogs may change their eating habits (getting hungrier, appetite loss) while others may continue as usual.
My dog definitely gets more clingy when she gets into heat and would like to cuddle all day long.
Estrus begins when the ovaries start releasing eggs for fertilization.
As I said before, estrus is the stage in which your dog is most fertile and most likely to get pregnant.
This stage can last from 3 to 21 days.
Female dogs will be more likely to accept male company and may be more eager to interact with them in a flirtatious manner.
There is a little trick that you can try to find out if your dog has entered this crucial stage and that is to touch/scratch the area where the tail begins.
If your dog is in estrus, she will curl her tail to one side to get it out of the way for mating.
This is called “flagging” and is something I can observe every time my dog goes into heat.
Another sign to look out for is the discharge which turns from bloody red to more light or watery pink.
After the estrus stage comes the diestrus which marks the end of the fertile period.
The swelling of the vulva and the bleeding will subside and the potential love interests will become less interesting.
As the second longest stage, it lasts for about 60-90 days.
The Anestrus stage is the final stage and lasts 100-150 days until the next heat cycle starts.
Can a Dog Get Pregnant While Bleeding?
Dogs can get pregnant while bleeding and this is actually the time when they are most likely to. This is usually marked by a light pink discharge.
Sometimes the bleeding nearly stops and owners think that their dog is no longer in heat when in reality they are at their most fertile stage.
If you want to prevent unwanted pregnancy, this is the time when you should stay away from male dogs the most.
It’s also important to note that sperm can survive for about a week in the reproductive tract and can get your dog pregnant up until the end of her heat cycle.
Pregnancy can happen without a tie so any mounting needs to be prevented.
Can a Dog Get Pregnant When Not in Heat?
Dogs cannot get pregnant when not in heat since there are no eggs being released for fertilization. However, it can be difficult to spot the specific heat stages.
Only looking out for bleeding, etc. is not a safe method to prevent unwanted pregnancies.
Every dog is different when it comes to cycle length, symptoms, and how often they occur.
Male dogs can also tie with your dog whether she is in heat or not and may be interested to do so year-round.
You can find out more about that in my article How Many Times Should a Dog Mate to Get Pregnant?
Can a Dog Get Pregnant Anytime?
A dog cannot get pregnant anytime as she must mate within the short fertility window during her heat or sperm must have survived in the reproductive tract until this stage.
However, the estrus cycle can go unnoticed if your dog has few symptoms and very subtle bleeding.
This can shock owners when they suddenly discover that their female dog is pregnant without having noticed the previous heat.
If you have an unspayed dog, always keep a close eye on them and do not leave them anywhere unattended, not even in your yard.
I have come across many stories where owners will find a strange male dog from the neighborhood inside their own yard while their unfixed dog was outside.
The same applies to owners of unfixed male dogs.
It is also your responsibility to keep your dog from mounting other dogs to prevent unwanted pregnancies and also to prevent bothering them.