Things to Consider
Pregnancy is a serious medical condition with potential risks for the dam and for her puppies. One of the worst things that can happen during pregnancy is abortion. Abortion occurs when one or more puppies are born before they can live successfully outside the womb. Fortunately, abortions aren’t especially common in domestic dogs, but they do happen and are devastating to the dam and her owner.
Nutritional imbalances can injure the female and cause serious birth defects in her puppies. This can happen when well-meaning owners try to enhance their dog's health and the health of her litter by giving vitamins, minerals and other supplements beyond those contained in her high-quality diet. A pregnant dog should not be fed supplements – especially calcium and phosphorus - without the guidance of a knowledgeable veterinarian. Over-supplementation during pregnancy can throw off the dam’s internal nutritional regulating mechanisms and increase her risk of developing eclampsia (“milk fever”) after she whelps.
Obese pregnant dogs, like their human counterparts, can develop blood sugar irregularities, especially low blood sugar (hypoglycemia). High blood pressure (hypertension) can also occur during pregnancy in obese dogs. Owners should closely monitor their dog's diet, exercise, body condition and overall health to help her maintain an appropriate weight throughout her pregnancy.
Risk of Infection
A number of organisms can cause infections in a pregnant dog, with serious consequences to her and her puppies. Brucella canis is the only bacterial organism known to cause infertility in female dogs. It can also cause resorption of embryos early in gestation and, most commonly, abortion of fetuses late in gestation. Both live and dead puppies can be born to infected females; living puppies usually die within hours to days. The dam’s reproductive tract can also be infected by Escherichia coli, Streptococcus, Salmonella and Campylobacter bacteria. The canine herpesvirus (CHV) can cause loss of a previously confirmed pregnancy or delivery of dead or abnormal puppies. Healthy puppies, small weak puppies and lifeless puppies can all be whelped in the same litter by a dog infected with CHV. Infected neonates may be mummified or macerated, with dead and disintegrating extremities.
Many drugs used to treat animals have not been tested for safety in pregnant dogs in terms of their potential effect on the pregnancy and fetal development. Some drugs are known to be risky to use during pregnancy, including:
- Chloramphenicol – decreases puppy bone marrow development
- Aminoglycoside antibiotics – toxic to the developing central nervous system (neurotoxic)
- Tetracycline – can cause malformations in bones and teeth
- Anesthetics – can cause respiratory depression in fetuses
- Corticosteroids – can cause abortion, fetal death and birth defects such as cleft palate
- Estrogenic/Androgenic compounds – can cause malformations in the genitalia and urinary tract
Pregnant dogs should not be given over-the-counter or prescription medications without the approval of their veterinarian. Many flea, tick and heartworm preventatives can be safely given to dogs during pregnancy, but this should only be done under the guidance of a veterinarian.