How do you know if a dog's in heat, or how to know if your dog is in heat when changes are subtle? In an unspayed female, PDSA, Blue Cross and the American Kennel Club note that a swollen vulva, bloody vaginal discharge, increased licking of the area, or behaviour changes (such as restlessness, clinginess, or frequent urination) may suggest a season. Because these signs do not replace a veterinary diagnosis—and worrying bleeding, unusual discharge, or feeling unwell can indicate illness—keep her separated from intact males immediately and contact your vet whenever you are uncertain or she seems unwell.
| Record item | What to note and manage right now | Critical boundary |
|---|---|---|
| Observed physical & behaviour signs | Date noticed, vulvar swelling, bloody discharge, extra licking, urination changes, or seeking/avoiding company (PDSA / Blue Cross / AKC). | Signs can be subtle and do not confirm a healthy heat cycle on their own; never dismiss lethargy or illness as hormonal (PDSA). |
| Contact with intact males | Whether any unneutered male dog—including a household relative—had access to her indoors, in the garden, or on a walk. | If mating happens, contact your vet immediately and never pull mating dogs apart (Blue Cross). |
| Separation & daily management | Who supervises doors and garden breaks, how intact males are kept in separate spaces, and quiet on-lead walks away from other dogs (PDSA / Blue Cross / AKC). | Hygiene pants or towels only catch discharge—dog pants do not prevent mating, and calendar dates alone do not set a safe release day (PDSA / AKC). |
| Questions for the veterinary clinic | Exact signs seen, any possible male contact, current comfort/appetite, and individual timing for future spaying. | Call the clinic promptly for painful swelling, heavy or foul discharge, unwellness, or accidental mating rather than waiting to build a full timeline. |
Arrange daily care
Per PDSA and Blue Cross guidance, separate her from intact males, including household relatives, and supervise garden access closely.
Name who will supervise and how the dogs will use separate spaces. Explain the arrangement to anyone taking over; do not assume the next caregiver knows which dog is behind a closed door.
The American Kennel Club advises using a lead on quieter walks away from other dogs. Avoid dog parks and daycare; choose home activities if avoiding loose dogs is impractical.
Dog in heat behavior
Keep routines familiar and respect her choice of company or space.
Towels or dog pants can help protect furnishings from discharge, but both PDSA and AKC stress that pants do not prevent mating.
When to call
PDSA advises contacting your vet about worrying bleeding, painful swelling, unusual discharge or feeling unwell; do not dismiss illness as hormonal.
Blue Cross stresses that if accidental mating occurs, you should contact your vet immediately—and never pull mating dogs apart, as forcing separation can cause severe injury to both dogs.
Tell the veterinary team what you actually noticed and whether contact with a male occurred. Leave unknown details unknown rather than delaying the call to reconstruct a timeline.
Agree what happens next
Discuss ongoing care and individual spay timing with your vet. Bleeding changes or calendar dates do not establish a safe release day.
For an appointment the clinic arranges, our dog vet-visit preparation guide helps organize questions and the handover. Contact the clinic first about a current concern.
