When a female dog is in heat (called estrus), she has a bloody discharge from her vulva—similar to a human period or menstruation. But that's where the similarities end. While humans experience a menstrual cycle every 28 days on average, dogs' estrous cycle is six months or more.
Dogs in Heat and the Estrus Cycle
Do female dogs have periods? Well, yes, but they are a part of what is properly called an estrus cycle. You may have also heard of a dog as being "in heat" or "in season" during this time, and the estrus cycle is sometimes called a "heat cycle."
The first signs your dog is in heat are the swelling of her vulva and bright red bloody discharge. This stage is called proestrus. "There will be lots of licking," Nielsen says. A dog in heat can bleed for around seven to 10 days.
Dogs don't menstruate like humans, but they do have heat cycles, in which they can have some vaginal discharge or bleeding. During this time, they are fertile and able to reproduce. The heat cycle typically lasts between 2-4 weeks and occurs every 6-12 months in adult female dogs (or every 4-6 months in puppies).
Dogs usually bleed during the proestrus period – when the body prepares for the season or the 'oestrus' period. This occurs 7-10 days before she comes into season.
The dog estrous cycle is made up of four stages. These are the proestrus, estrus, diestrus, and anestrus. The proestrus is the most obvious stage, while the other stages are more subtle.
Q: Should I let my dog have a heat before I spay her? A: Medically, it's better to spay your dog before their first heat. It greatly reduces the risk of mammary tumors. People who wait to spay their dogs until after their second heat greatly increase the risk of mammary tumors in their pets.
There is no menopause in dogs, so older female dogs continue to have heat cycles, but they will become further apart and her fertility will decrease.
Heat usually lasts between 2-4 weeks. Early in the cycle, a female dog may not be receptive to male dogs, although some are receptive through the entire cycle. It can be shorter or longer and you'll know the cycle is over when all her vulva returns to its normal size and there's no more bleeding or discharge.
When should I spay my female dog? We recommend waiting until your dog is at least over 6 months and likely even older for larger dogs. The benefits are much more pronounced in larger dogs, but there is not a lot of difference for lap dogs.
Female dogs cycle into heat on average every six months. But this can vary, especially in the beginning, so it's a good idea to keep track. It can take some dogs 18-24 months to develop regular cycles. Small dogs will tend to go into heat more frequently, as much as three or four times a year.
Some signs of a female dog going into heat may include lower energy levels, more aggressive behavior, differences in leg-raising while urinating, urinating more often than usual, and even running away from home. This is unlike male dogs, who do not experience heat cycles.
As her cycle progresses, the texture and color of the flow changes to more of a straw-color. It is this discharge that produces a unique smell that is quite appealing to male dogs. The discharge and the accompanying smell is nature's way of alerting male dogs to the fact that a female is fertile.
Behavior & Pain While In Heat
A dog's body experiences lots of changes when she's in heat. Because of these changes, your dog may experience some changes in behavior and even some pain. Much like humans, female dogs experience cramps and hormonal changes when their bodies are preparing to mate.
Most dogs come into heat twice per year, although the interval can vary between breeds and from dog to dog. Small breed dogs may cycle three times per year, while giant breed dogs may only cycle once per year. When young dogs first begin to cycle, it is normal for their cycles to be somewhat irregular.
If your dog seems unusually tired, or not as interested in playing with you, it could be a sign they are beginning their heat cycle.
Increased vocalization: Dogs in heat may become more vocal to try to get attention, including moaning, whining, and crying. Increased urination: Female dogs may urinate more often as a way to attract a mate because their urine contains pheromones.
Some dogs experience a condition called silent heat, in which they do ovulate but the characteristic signs of being in heat, such as vulvar swelling and discharge, are not observed. Although rare, some dogs may also have an autoimmune disease that affects their ovaries and interferes with estrous cycling.
The short answer is- yes it will. Spaying and neutering both involve making permanent changes to your dog's reproductive system, whether male or female. Dogs' hormonal systems change based on their reproductive system, just like in humans! Hormones are in part responsible for some of our behaviors.
While most vets prefer to perform the surgery while your dog is not in heat, they can do so even when she is. The procedure involves the complete removal of her ovaries (and commonly, the uterus) to ensure that she can no longer become pregnant.
Agitated, nervous, or aggressive behavior: In the first phase of estrus, your dog might seem skittery or nervous. It might be aggressive towards other household pets, or even towards you. As estrus progresses, your dog may be aggressive towards other female dogs, but welcoming to male dogs.
When female dogs enter the estrus portion of their cycle, vocalizing becomes even more common, particularly if you also have an intact male in the house. Moaning, whining, crying, and even screaming serve as a form of "mating call" to male dogs throughout the neighborhood.