Pseudopregnancy – frequently called "false pregnancy" – is common in intact (non-spayed) female dogs somewhere between 6 to 12 weeks after a heat cycle (called "estrus"). All normal bitches go through a stage of their reproductive cycle after estrus that is called the luteal phase, or "diestrus," where the hormone progesterone is produced at elevated levels, whether or not the animal is pregnant. During this time, animals develop most if not all of the signs of pregnancy, even when they are not pregnant. False pregnancies are easy to diagnosis, and normally treatment is unnecessary.
Symptoms of False Pregnancy in Dogs
The clinical signs of pseudopregnancy range from subtle to extreme. In some cases, they are so convincing that even experienced breeders are confident that a litter is coming. Signs include behavioral changes (anorexia or appetite fluxuations, excessive vocalization, whining, restlessness, signs of aggression, depression, or anxiety), maternal behaviors (nesting, digging, mothering or "adopting" of toys, stuffed animals or other inanimate objects), mammary problems (engorgement, lactation, licking of the mammary glands/self-nursing), vomiting and abdominal distention.
There is no known age or breed predisposition for this condition, although some experts indicate that Dalmatians, Basset hounds and Pointers may be more frequently affected. Interestingly, the phenomenon of non-pregnant bitches developing milk and actually lactating may have had some functional importance in evolution, when mature canine bitches (such as wolves) without puppies had to nurse orphaned litters in the wild.
Diagnosing False Pregnancy in Dogs
It is not difficult to diagnose false pregnancy in dogs. If the animal went through a heat cycle 6 to 12 weeks before the onset of clinical signs of pregnancy, whether or not she was known to be bred during that time, a veterinarian will take a thorough history of her recent physical and behavioral conduct and will perform a complete physical examination. Radiographs and ultrasound can be used to conclusively confirm the presence or absence of pregnancy, and no additional blood, urine or other tests should be necessary. Of course, since a dog's gestation period is only roughly two months, if 3 or more months have passed since the end of a bitch's previous heat cycle it is highly unlikely that she is truly pregnant.
Radiographs and ultrasound are also useful to rule out the possibility of a serious condition called "pyometra," which is an accumulation of pus inside the uterus from bacterial infection. Pyometra can be life-threatening and must be treated as an emergency. It is uncommon, but still possible, that signs of false pregnancy will appear in a bitch who actually became pregnant and then either aborted or reabsorbed her puppies, in which case the risk of developing pyometra increases dramatically.
If treatment is appropriate, a veterinarian can determine what steps should be taken. Some owners apply hot or cold-packs to swollen mammary glands, but experts discourage taking any steps that stimulate lactation and so these treatments are not recommended. Owners may use an Elizabethan (cone) collar and remove any inanimate puppy-substitutes that the bitch is hoarding to try and hasten resolution of the false pregnancy. In more severe cases, veterinarians may recommend removing food and water for 6-10 hours for several nights in a row to reduce lactation. Dieuretics and mild sedatives may also be prescribed to assist in this process. A dog going through a false pregnancy should not be spayed (ovariohysterectomy) until all signs of the condition have resolved. If the owner wants a litter from an affected animal, she probably should be bred on her next cycle.
Hormonal therapies have been used to manage false pregnancies as well. Because these can change over time, only a veterinarian is best able to advise owners about the most current treatment protocols at any given time.
Pseudopregnancy is not a "disease" per se but rather is a clinical syndrome involving an exaggerated response to normal hormonal changes. Owners of bitches going through a false pregnancy should be reassured that even if left untreated, the condition almost always will resolve on its own.