What is a miscarriage?

A miscarriage is defined as a spontaneous abortion, or loss of a fetus during pregnancy.

Miscarriages can occur at any time during the pregnancy; however, outcomes may differ based on when the miscarriage occurs. These can occur either in the early stages (first 45 days of pregnancy) or in later stages of the pregnancy (after 45 days) when fetal skeletal development may be present.

In miscarriages that occur in the early stages, embryos are often resorbed by the body and may be undetected in many cases (unless a pregnancy was known via ultrasound prior). If some embryos survive, they may go on to full-term pregnancies.

Miscarriages that occur later in pregnancy (after 45 days when fetal skeletons are starting to be formed) may result in still-born puppies (either on or before the due date) or mummification of the puppy.

• Stillborn puppies are full-term puppies (capable of independent life) that are born dead. The death may occur a few hours, days, or minutes before birthing.
• Mummified puppies are fetuses that have been walled off by the body (in a protective membrane) within the uterus. Generally, these do not pose a risk to the female. In some cases, however, infections can occur that may affect the female.

Causes of Miscarriages in Dogs

The most common cause of miscarriages in dogs are infections - these can be bacterial, viral, or parasitic in nature.

In otherwise healthy dogs, Brucella canis, a bacterial infection, can result in miscarriages and infertility in late-stage pregnancies in dogs. Brucella canis is transmitted through interstitial fluid during mating (from an infected male) or when the female is in contact with the birthing fluids of an infected female. Other bacterial infections may be opportunistic and normally present in healthy females (such as E.coli and Staphylococcus spp.) can also result in miscarriages due to toxins produced by these bacteria.

Canine parvovirus and canine herpes virus can result in fetal death in utero. Less commonly, parasitic infections such as Toxoplasma gondii and Neospora caninum have also been associated with miscarriages in dogs.

There are noninfectious causes of miscarriages including hormonal imbalances. Progesterone is a hormone that is required for maintaining a normal pregnancy. Low progesterone levels can trigger spontaneous abortions in dogs. Low progesterone levels can be due to medications administered, or due to maternal and placental factors.

Symptoms of a Miscarriage in Dogs

In most cases, miscarriages go unnoticed unless an ultrasound has confirmed pregnancy early on and then repeated just before the due date.

The most common sign of miscarriage is abnormal discharge from the vulva during pregnancy. Normally, females may have clear to mucoid/pink tinged and odorless discharge between 30-35 days gestation. If the discharge has blood or pus, is brown/green or black tinged, or is malodorous, this is considered abnormal and may indicate signs of pregnancy complications. Some females may also have abdominal pain and fever.

How do we treat and prevent miscarriage in dogs?

If you suspect that your dog may be having a miscarriage, seek medical care immediately - either with your primary vet or with an emergency clinic if your primary vet is unavailable.

Your vet may perform an abdominal ultrasound to evaluate the puppies better and present you with the best plan. An ultrasound will provide more information to your vet than x-rays in most cases. Your vet may also check your dog’s progesterone levels and general bloodwork to further evaluate your dog’s overall organ function.

If an infectious cause is resulting in fever in the female, she may be treated with antibiotics or fluids (supportive care) to resolve the infection and prevent loss of pregnancy. If her progesterone is low (which may not be apparent immediately as the results of this test may take some time), progesterone supplementation may be provided.

A C-section may be performed to save the mother or fetuses - performing a culture of her vaginal fluid or from the decreased fetus may be helpful in gathering more information and preventing future loss of pregnancies. A spay procedure may be performed if the pregnancy was accidental at the time of the c-section to prevent further pregnancies.

Read more:

Caring for Your Pregnant Dog

False Pregnancy in Dogs

What is Responsible Breeding?

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