Breeding guide: the dog heat cycle
The Dog Heat Cycle Explained: Stages, Signs and Timing
The dog heat cycle has four stages and comes round about every six months for most females. The part owners notice, with swelling and discharge, lasts two to three weeks. A first heat can arrive as early as four or five months in toy breeds, so it helps to know the signs ahead of time.
The four stages of the dog heat cycle
| Stage | Typical length | What you see |
|---|---|---|
| Proestrus | 6 to 11 days on average. Can range from 3 to 21. | Swollen vulva and bloody discharge. Males are interested, but she is not yet receptive. |
| Estrus | 5 to 9 days on average. Can range from 1 to 20. | She accepts a male. Discharge often lightens to pink or straw-colored. This is the fertile stage. |
| Diestrus | About two months if she is not pregnant | Signs of heat fade and she rejects males |
| Anestrus | About four months or more | No outward signs. The uterus recovers. |
These figures come from Cornell University’s Riney Canine Health Center and the American Kennel Club (Cornell, AKC). The ranges are wide, so one dog’s pattern can look quite different from another’s.
When does the first dog heat cycle start?
It depends on size. The AKC notes that toy breeds can come into heat as early as 4 or 5 months, while some giant breeds may not cycle until around 2 years old. Cornell gives an overall range of 6 to 24 months, with smaller breeds earlier than larger ones.
That matters for small breeds like Havanese, Toy Poodles and Havapoos. A young female can become pregnant on her first heat, long before she is physically mature, so owners need a plan before she is five months old.
How often does a dog heat cycle come round?
Most females cycle about twice a year. Cornell puts the usual gap between heats at 5 to 11 months. A few breeds, including the Basenji and the Tibetan Mastiff, typically cycle only once a year.
Dogs do not go through menopause. According to the AKC, females keep cycling into old age, although fertility falls and some heats become “silent”, with no visible discharge.
Signs your dog is in heat
- A swollen vulva
- Bloody discharge, which later thins and lightens
- More frequent urination and extra licking
- Sudden interest from male dogs
- A change in mood: clingier, more withdrawn or short-tempered with other dogs
The fertile window sits inside estrus. The AKC describes it as running from a couple of days before ovulation to about five days after. Because the outward signs do not line up neatly with ovulation, breeders rely on a veterinarian’s hormone testing to time a breeding, not on the calendar.
Managing a heat at home
- Keep her on a leash outdoors and never leave her alone in a yard, even a fenced one
- Skip dog parks and daycare for about three weeks
- Use washable dog diapers or cover furniture if the discharge is a problem
- Keep intact males in the household completely separate
If you do not plan to breed, talk to your veterinarian about spaying. Cornell notes that spaying prevents heat cycles and also prevents pyometra, a common and serious infection of the uterus. If she is in heat now, vets generally advise waiting about two months before surgery.
From the dog heat cycle to a planned litter
For a breeder, the heat cycle sets the calendar for everything else: health testing is finished first, ovulation is timed with the vet, and puppies arrive about 63 days later. Read how long dogs are pregnant for what happens next, or see how we health test our parent dogs before any litter is planned.
Related guides
- Puppy Development Stages: Week by Week From Birth to 12 Weeks
- How Long Are Dogs Pregnant? A Week-by-Week Guide to Dog Pregnancy
- When to Spay or Neuter a Small Dog: What Vet Guidelines Say
- How Many Puppies in a Litter? Averages by Dog Size
- Dog Health Testing Before Breeding: What OFA, Eye, Heart and DNA Tests Cover
See all our puppy guides, read about our health testing, or meet our Havapoo puppies for sale and Goldendoodle puppies for sale.
Sources
- Cornell University College of Veterinary Medicine, Dog Estrous Cycles
- American Kennel Club, How Long Are Dogs in Heat?
- American Kennel Club, How Often Do Dogs Go Into Heat?
- Merck Veterinary Manual, Breeding Management of Bitches
This article is general information and does not replace advice from your veterinarian.
Curious about our next litter?
We announce a litter once we are confident in it. Ask what is planned. Ready to meet a puppy? See our available puppies.