Why does the vulva wrinkle approaching ovulation?

EDUCATIONAL POST

Understanding Vulval Changes During the Canine Heat Cycle

During the canine oestrous cycle, changes in the vulva are driven by hormonal fluctuations — not guesswork, myths, or “rules of thumb”.

In pro-oestrus, rising oestrogen causes increased blood flow and fluid retention, resulting in a vulva that appears swollen, smooth, firm, and shiny. Despite the obvious physical changes, the bitch is not yet fertile at this stage.

As the cycle progresses into oestrus, oestrogen levels fall and progesterone begins to rise. This hormonal shift reduces blood flow and tissue fluid, causing the vulva to soften and decrease slightly in size. Because the tissue has been previously stretched, it may appear wrinkled or puckered as it relaxes.

This wrinkling is commonly observed around ovulation or shortly after, often alongside behavioural receptivity and changes in discharge. However, vulval appearance alone is not a reliable indicator of ovulation.

Breed, age, parity, and individual hormonal patterns vary widely. For this reason, best practice in canine fertility management relies on vaginal cytology and progesterone testing, with external signs used only as supportive information.

Key Learning Point:

Visual changes provide context — objective testing provides accuracy.

#CanineFertility

#CanineReproduction

#CPDEducation

#ProfessionalBreeders

#CanineOvulation

#VaginalCytology

#ProgesteroneTesting

#BreedingBestPractice

#CanineHeatCycle

#ProPetTraining