Historically, veterinarians have expressed concerns about pediatric spay and neuter. The concerns have focused on either potential
long-term physiologic effects or anesthetic risk.
The adverse physiologic effects mentioned have been obesity, stunted growth, musculoskeletal disorders, perivulvar dermatitis,
puppy vaginitis, feline lower urinary tract disease, and urinary incontinence. Most concerns appear to be unfounded.
Obesity. Obesity is a multifactorial problem with a tendency to occur regardless of the age at which an animal is spayed or neutered.
A long-term study conducted by researchers at Cornell University followed 1,842 dogs that underwent gonadectomy and were adopted
from a shelter before 1 year of age and followed for up to 11 years. The results revealed a decrease in obesity for male and
female dogs that had early-age gonadectomy.12
Stunted growth. Initial concerns that pediatric neutering may result in stunted growth have proved to be false in dogs. Removal of the hormonal
influence actually results in delayed closure of growth plates.13 The long bones of dogs that undergo pediatric neutering are a little longer than those of animals neutered after 6 months
of age; however, the growth is not disproportionate, and the curve is the same.13 There does not appear to be any clinical relevance to the delayed physeal closure.13
Hip dysplasia. Some veterinarians have questioned if pediatric spay or neuter results in an increased incidence of hip dysplasia in dogs.
Research on this subject has proved to be equivocal. A study at Texas A&M University showed no increase in hip dysplasia,14 while a study at Cornell University showed a slight increase in incidence.12 Interestingly, the Cornell study also showed that dogs sterilized at a traditional age were three times more likely to be
euthanized because of hip dysplasia.12
Perivulvar dermatitis. Perivulvar dermatitis has been documented in intact and spayed female dogs. The age at the time of neutering appears to have
no significant influence on the incidence.13
This condition is related to a recessed vulva and is made worse by obesity.
Puppy vaginitis. The incidence of puppy vaginitis is the same regardless of the age of the dog at the time of ovariohysterectomy.12
Feline urinary obstruction. The suspicion that pediatric castration would decrease the diameter of the penile urethra in cats and, thus, lead to urinary
obstruction has proved to be unfounded. The diameter of the penile urethra in an adult male cat does not vary between animals
neutered at 7 weeks or at 7 months of age or from intact males.15-17
Urinary incontinence. Studies have shown differing conclusions with respect to estrogen-responsive urinary incontinence in dogs. The Cornell study
mentioned above revealed a slightly greater risk of urinary incontinence in dogs spayed earlier than 12 weeks of age,12 while the Texas A&M study showed no difference.14 A third study showed a higher incidence of urinary incontinence in dogs spayed after their first estrous cycle.18