What this means
A bitch's heat cycle usually repeats at its own rhythm, but that rhythm differs between dogs and changes with age. Changes that cause concern are heats that are late or stop, heats that are irregular or unusually long, or a bitch that does not conceive after mating. A useful aid is a heat calendar in which the start and end dates of each heat are written down.
Such changes are not a disease in themselves but a sign that the hormones, ovaries, womb or general health may be disturbed. A vet has to find the cause by examining the bitch and running tests. Do not try to guess at home or to alter the bitch's cycle yourself.
It is especially important to know that an unspayed bitch that becomes dull after a heat, drinks more, vomits or has unusual discharge from the vulva needs to see a vet without delay, because these signs can point to a serious problem with the womb. Note down the heat dates, her age, the colour of any discharge and any other changes you notice.
Possible causes
These are things that can cause this sign. It is not a diagnosis, and they are not equally likely for your dog.
-
A hormone imbalance
When hormones work unevenly, the cycle can become irregular or stop. A vet finds the cause.
-
Changes in the ovaries
In some cases ovarian function is disturbed or changes appear in the ovaries. This affects the rhythm of heat.
-
Inflammation or infection of the womb or reproductive tract
Inflammation or infection can disturb the cycle and lower the chance of conceiving. Sometimes it threatens the bitch's health.
-
Thyroid or other general disorders
When the body's general function is disturbed, it can show in the heat as well. A vet checks whether there is such a cause.
-
Age
In young bitches the cycle is still settling, and in older bitches the rhythm may change. It is still worth discussing with a vet.
-
Factors on the male side or with mating
Sometimes conception fails not because of the bitch but for other reasons. A vet can assess both sides.
What else to watch for
These observations help your vet build the picture faster. Note down what you saw and when.
- When the last heat was and how long it lasted
- How much time passed from the previous heat to the present one
- Whether any discharge is unusual: dark, pus-like or foul-smelling
- Whether the bitch has started to drink more, vomit or become dull
- Whether appetite, weight or coat have changed
- How old she is and whether her cycle used to be regular
When to book a routine visit
If a bitch's heats have stopped, become irregular or she does not conceive, book a vet visit. Bring notes of the heat dates and mention any discharge.
Related conditions
Conditions whose entries mention this sign. The list is somewhere to read on, not a way to reach a diagnosis.
Body systems: General health