Abortion is one of the most distressing medical conditions faced by breeders of domestic dogs. Often, there are no recognizable signs that an abortion has taken place, especially if the miscarriage happens early in the pregnancy. In an early abortion, many bitches will actually ingest the placental and fetal tissues that they expel during an abortion as part of their normal hygiene and self-grooming, leaving no trace of the failed litter. Most canine miscarriages occur during the last few weeks of pregnancy; these tend to be easier for an owner to detect, because the aborted puppies are more fully developed and recognizable. If the bitch does not start to whelp puppies by about 63 days after the presumed date of conception, the owner should suspect either an abortion or, more likely, reabsorption of the litter.
When an owner suspects that her bitch may have had a miscarriage, she should take her to the veterinarian for a reproductive evaluation. The veterinarian assessing the bitch usually will draw a blood sample to identify any infectious organisms in circulation and also to evaluate the bitch’s blood progesterone level. Serum progesterone should be greater than 2 nanograms per milliliter to successfully maintain a normal pregnancy. Blood tests can also be run to analyze circulating thyroid and adrenal hormone levels. Hypothyroidism (low levels of thyroid hormones) and hyperadrenocorticism (high levels of adrenal hormones) can predispose a bitch to have an abortion. The veterinarian may take a vaginal swab sample and submit it to a pathology laboratory for culture and sensitivity, to identify any infectious agents that may be present in the birth canal. If the owner has recovered any placental or fetal tissues, those should also be submitted to the pathology laboratory for evaluation. Vaginoscopy is also available at some veterinary hospitals. This involves using a wand-like instrument with a camera at its tip to visualize and assess the health of the entire length of the bitch’s vagina.
When an abortion is caused by Brucellosis, the Brucella canis organisms will be expelled in massive numbers in the aborted placental and fetal tissues. These organisms are extremely infectious to other animals, including people. Owners should be very careful when handing any tissues expelled by an aborting bitch. People who are immunocompromised are especially at risk for becoming infected by Brucella canis.