Canine maternal hydrops… I first heard about this term a few years ago, when my former boss called me because he was questioned on this disorder. Interestingly, the question came from Canada (at this time I never thought that I would one day live here!)…
Recently my colleague Pierry McLean sent me the following linkhttp://www.kattwalkgolden.com/maternal_hydrops.htmlwhere I could read a long article on what the breeder called “canine maternal hydrops”. She mentioned that “there is a serious lack of available information for Maternal Hydrops in dogs”. Well, to tell the truth, there is no information at all!
When speaking about hydrops, veterinarians generally refer to “dropsy of the fetal membranes and fetus”. Basically, this means that there is an abnormal accumulation of fluid in one of these fetal sacs (there are two fetal sacs in mammals, the allantois and the amnios) or in the fetus itself. The dropsy of the fetus’s conditions are well known among repro vets (hydrocephalus, fetal ascites, fetal anasarca). However, the situation is completely different when it comes to the dropsy of the fetal sacs (disorders referred to as hydrallantois and hydramnios). Hydrallantois is only mentioned once in the scientific literature in the bitch (Smith& Oaksford, 1972, so as you can see not a really recent reference) and there is no mention at all of hydramnios in the canine species.
These diseases are essentially described in the cow, and, to a lesser extent, in the mare. In these species, hydrallantois is far more common than hydramnios and can indeed lead to life threatening conditions in certain cases. This large amount of fluid indeed compresses all the major blood vessels, leading to edemas, cardiac malfunction, and eventually death. To date, nobody really knows what the initial cause is… A malfunctioning placenta has always been reported, with no associated infectious signs. Interestingly, the incidence of the disease seems to be higher with pregnancies of bovine clones. The treatment is rather simple: stop the pregnancy (if it occurs early during pregnancy) or go for a c-section in later cases.