Associations between age, parity, hormonal therapy and breed, and pyometra in Finnish dogs

Study of pyometra in dogs in Finland

source: M. Niskanen and M.V. Thrusfield
Veterinary Record vol 143 no 18, October 31 1998
starts p493, 6 pages long

Pyometra is pus in the womb, and is a common affliction of entire bitches, which can be fatal, though treatment has improved survival rates. Other studies have found that bitches may be more vulnerable to pyometra if they are given oestrogen at a time when they have high levels of progesterone. Bitches are most likely to suffer this condition when they are between six and eight years old, though younger bitches can also be afflicted, and this could be linked to their being given oestrogen to avoid pregnancy. Other studies have found some possible links between breed and vulnerability, with Collies and Chow Chows among vulnerable breeds.

This Finnish study took place in a country where spaying is uncommon, and is based on 953 bitches with the condition, and 10,660 unmatched controls. A total of 219 breeds were recorded, and pyometra affected 112 of them. The mean age of affected bitches was 8.5 years, and median age 9.0 years. Bitches that had never had puppies (nulliparous) were more likely to be affected, There were not enough data to assess fully the impact of progestin therapy, though there is some evidence of a link between oestrogen therapy and pyometra in younger dogs. Breeds found to be at risk from this condition, according to this Finnish study include Golden Retrievers, Miniature Schnauzers, Irish Terriers, Rough St Bernards, Leonbergers, Airedale Terriers, Cavalier King Charles Spaniels, Rough Collies and Rottweilers, while Wire Haired Dachshunds and mongrels appear to have a low risk of suffering the condition.