Vaginal prolapse (prolapse of the uterus)

Causes and risk factors

The most common cause of vaginal prolapse is the influence of the female sex hormone oestrogen during heat. The oestrogen causes the vaginal mucosa to swell and contain more fluid. If there is not enough space in the vagina, the mucous membrane can be pushed outwards. This usually happens in the first half of the heat, when oestrogen is at its highest. In the second half of the heat, oestrogen decreases and progesterone increases, which can lead to a regression of the prolapse.

Some dog breeds are more prone to vaginal prolapse than others, for example Labradors, English Bulldogs, St. Bernards, Mastiffs, Springer Spaniels and Weimaraners. This could be due to a genetic predisposition or an increased sensitivity to oestrogen.

Other possible causes of vaginal prolapse are

• Vaginal tumors: these can be benign or malignant and lead to enlargement or inflammation of the vaginal mucosa. One example is transmissible venereal tumor (TVT), which is transmitted through sexual contact between dogs and can lead to a proliferating mass in the vagina.
• Birth complications: If a female dog strains hard during labor or if a puppy gets stuck, there can be an increase in pressure in the vagina that can cause a prolapse. This is a medical emergency and requires immediate veterinary attention.
• Excessive licking: If a dog constantly licks her vagina, this can cause irritation and inflammation of the mucous membrane, which can promote prolapse. The licking can be triggered by itching, pain or boredom.

Symptoms and diagnosis

The most noticeable symptom of vaginal prolapse is the presence of a pink or red mass protruding from the vagina. The mass can vary in size, from a few centimeters to the size of a tennis ball or larger. The mass is usually moist and shiny and may bleed or ulcerate.

Vaginal prolapse can be very uncomfortable for the dog and can lead to the following symptoms:

• Frequent licking or biting of the vagina
• Difficulty or pain when urinating
• Loss of appetite or interest in activities
• Depression or lethargy
• Fever or signs of infection

The diagnosis of vaginal prolapse is made by a clinical examination of the dog and an inspection of the vaginal mass. The veterinarian will also try to determine the underlying cause of the prolapse by performing blood tests, urinalysis or tissue samples.

Treatment and prevention

The treatment of vaginal prolapse depends on the severity, cause and timing of the onset. In some cases, the prolapse may resolve on its own when the heat ends or the birth is complete. In other cases, medical or surgical intervention is required to reduce the prolapse and prevent it from recurring.

Possible treatment options include:

• Hormone therapy: this consists of administering progesterone or other hormones that can reduce estrogen levels and reverse the prolapse. This can be done orally, injectably or as an implant. However, hormone therapy has some side effects, such as an increased susceptibility to uterine inflammation, diabetes or breast tumors.
• Manual reduction: This consists of carefully pushing the prolapse back into the vagina and securing it with a bandage or suture. This can be done under local or general anesthesia. However, manual reduction is not always successful and can lead to bleeding or infection.
• Surgery: This consists of surgically removing the prolapse and partially or completely closing the vagina. This prevents the prolapse from recurring, but also makes subsequent breeding impossible. Surgery is the most effective method of treating vaginal prolapse, but requires general anesthesia and a longer recovery period.
• Neutering: This consists of removing the dog's ovaries and uterus, which lowers oestrogen levels and prevents vaginal prolapse. Neutering is the best preventive measure for vaginal prolapse, but it also has some disadvantages, such as weight gain, an increased risk of urinary incontinence or a change in behavior.