I’ve had female dogs for a few years and never found patched of blood laying all around the house. Do dogs suffer from PMS?
Has she been spayed?
If so then she won’t be having periods for the rest of her life.
Well, then why isn’t there blood around the house?
Dogs have tongues that they use for cleansing.
Maybe the amounf of discharge varies by the individual dog. I’ve seem some folks put “diapers” on female dogs in heat.
Also, perhaps female dogs can clean off this area of their body by licking?
Not that I was planning to eat dinner tonight or anything, but why do they lick the blood off? What do they care if they bleed around the house…
Are you sure those are not chastity belts? 
This was exactly what my dog used to do, she even licked up drops on the floor. Maybe your dog does the same thing? If so this is why you don’t see drops around the house. Especially if your dog spends most of her time outside where unlicked drops would be less visible.
They do not care, however dogs loooove the taste of blood.
We didn’t have our ‘bitch’ spayed for years (until the depression and phantom pregnancies set in) I remember seeing a wee bit of blood round her rear end once or twice only and a couple of times noticed a smear of blood in her bed or somewhere she’d been lying for a long time.
This strawberry yogurt that I was about to have for dessert has somehow lost all of its appeal.
Humans menstruate too you know… (about half of them)
Yes They do. My friends female German Shepard hopped into the back seat of my car, with white vinyl interior, while she was in heat. Well anyway he had a lot of red stuff to clean up. Thank God it was vinyl.
I beg to differ. Leaving a trail of blood the leads directly to you is what people usually refer to as a "bad thing"™ in the wilderness. Too easy to track for larger predators, who might assume it’s a wounded animal and track it leading to an unpleasant encounter.
You haven’t answered whether she’s sapyed or not. If she’s spayed then she won’t go into heat and won’t bleed.
That’s what I was going to postulate. Wouldn’t it be instinctive to clean yourself of any blood so as not to leave a scent that indicates you are injured prey?
What purpose does it serve the female dog to bleed from the walls of her vagina? I googled this and all I got were sites that said yep, it comes from the vagina, but not WHY.
Dogs are also known for their indiscriminate tastes in everything. If I don’t stop my terriers, they’ll eat from my cat’s litterbox.
“Hey, Rex! Look! He put the tootsie rolls out again!”