Urogenital Disorders Urinary incontinence is common in spayed female dogs, which can occur soon after spay surgery or after a delay of up to several years. The incidence rate in various studies is 4-20% for spayed females compared to only 0.3% in intact females38. Urinary incontinence is so strongly linked to spaying that it is commonly called “spay incontinence” and is caused by urethral sphincter incompetence, though the biological mechanism is unknown. Most (but not all) cases of urinary incontinence respond to medical treatment, and in many cases this treatment needs to be continued for the duration of the dog’s life.
A retrospective study found that persistent or recurring urinary tract (bladder) infections (UTIs) were 3-4 times more likely in spayed females dogs than in intact females. Another retrospective study found that female dogs spayed before 5 ? months of age were 2.76 times more likely to develop UTIs compared to those spayed after 5 ? months of age. Depending on the age of surgery, spaying causes abnormal development of the external genitalia. Spayed females were found to have an increased risk of recessed vulva, vaginal dermatitis, vaginitis, and UTIs. The risk is higher still for female dogs spayed before puberty.