Causes of Canine Abortion
There are a number of different things that can cause a pregnant bitch to abort one or more of her puppies. These include excessive inbreeding, congenital abnormalities, poor nutrition, endocrine disorders such as hypothyroidism, hyperadrenocorticism also known as Cushing’s Disease; ingestion of toxic substances, exposure to certain pharmaceutical agents such as chloramphenicol, administration of high doses of glucocorticoids (steroids), systemic illness accompanied by a high fever, abnormal ovarian function, cystic endometrial hyperplasia, pyometra, trauma, lethal chromosomal abnormalities, stress, old age and bacterial, viral or fungal infections.
One of the most common causes of still-births in dogs is Brucellosis, which is an infection caused by the Brucella canis bacteria. Other infectious agents that can cause abortions in dogs include Listeria monocytogenesEscherichia coli, Campylobacter, Salmonella, Streptococcus, Staphylococcus, Chlamydia, canine herpesvirus, Neospora caninum, Mycoplasma, Pasteurella, Klebsiella, Pseudomonas, canine Distemper virus, Parvovirus and Toxoplasma gondii. Abortion can also be caused by immune-mediated hemolytic anemia and by a number of neoplastic (cancerous) conditions.
Bitches who abort on successive pregnancies should be examined by a veterinarian for uterine infection or progesterone deficiency. A progesterone deficiency, called “hypoluteoidism,” happens when the ovaries don’t secrete enough progesterone to support attachment of the embryo to the uterine wall. If the bitch’s owner finds any fetal or placental tissue after an abortion, she should take it to her veterinarian, so that it can be evaluated by a pathology laboratory to help identify the cause of the aborted litter.
Preventing Canine Abortions
Sound management practices, including providing superior nutrition, regular vaccinations, internal and external parasite control and pristine environmental hygiene, are all important to a successful pregnancy. Once a bitch begins aborting her fetuses, it is very difficult to save the litter. However, if the dam’s serum progesterone levels are low and caught early enough, progesterone supplements can be given in an attempt to sustain the pregnancy to term. Progesterone supplementation probably is a good idea for bitches with a history of early-term abortions. Progesterone levels must be rigorously monitored throughout the entire pregnancy. Pregnant bitches should have limited contact with dogs other than those in their immediate family, and should be kept away from dog parks, dog shows and other areas frequented by dogs whose vaccination and health status is unknown.
Many intact bitches go through a pseudo-pregnancy, which is also called a false pregnancy. It can be difficult even for experienced breeders to differentiate between a false pregnancy and a true pregnancy, especially during the first month of gestation. Bitches going through a false pregnancy often have mammary gland enlargement and may produce milk. They also may dig and nest, much like pregnant bitches will do shortly before they give birth. When an owner has carefully planned a breeding and has conscientiously cared for her bitch during the subsequent two months, it is extremely disappointing to find out that the dog is not actually pregnant. Sometimes, nature just fools us.