False pregnancy (pseudocyesis) is a term used to describe the behavior and physical signs of pregnancy when they occur in a non-pregnant animal. The signs of false pregnancy usually occur 6 to 12 weeks after the pet's last heat cycle. This condition is common in dogs but rare in cats.Causes False pregnancy is caused by hormonal mechanisms that are poorly understood. In intact dogs, the reproductive system goes through several stages on a regular basis. Hormonal changes, primarily decreases in progesterone and increases in prolactin, are probably responsible for false pregnancies.
Some pets that were spayed during the diestrus phase of the reproductive cycle when progesterone level is high can have a false pregnancy even after they are spayed.
Some pets with hypothyroidism may have blood changes, which can cause stimulation of prolactin. This can also cause symptoms associated with false pregnancy.
If your pet has a false pregnancy, it will not interfere with her ability to be bred or have subsequent pregnancies.
Other conditions such as pregnancy, inflammation of the mammary glands (mastitis), cancer of the mammary gland or abdominal enlargement due to fluid accumulation, organ enlargement or infection of the uterus (pyometra) may cause similar signs to a false pregnancy. Your veterinarian may wish to examine your dog to make sure that she is healthy.
What to Watch For
Nesting behavior. Animals that are going through a false pregnancy will often attempt to make a nest by tearing up papers and blankets.
Mothering activity. During a false pregnancy, your pet may mother shoes, toys and other articles.
Mammary gland enlargement. The mammary glands may be large and secrete milk or serous fluid.
Mild signs of illness. Weight gain, mucoid vaginal discharge and abdominal swelling may occur during a false pregnancy; however, if your pet shows these signs and seems depressed or is lethargic, it would be wise to have her evaluated by your veterinarian to ensure that nothing else is wrong and that it is truly a false pregnancy.
Signs of illness. If your pet does not eat, acts lethargic, vomits, is depressed or you notice vaginal discharge (particularly one that is cloudy and foul-smelling), call your veterinarian as soon as possible. These may be signs of uterine infection, which is a serious and life-threatening condition.
Diagnostic tests for pseudocyesis may include:
History and physical examination. Your veterinarian will obtain a history of your pet's heat cycles and will ask you questions to try to determine whether or not there is any possibility that she was bred. This will help determine if she could be pregnant. Abdominal palpation will be done to feel for the presence of puppies; however, they can be difficult to feel.
Abdominal radiographs (X-rays). Radiographs may be taken to determine if there is a pregnancy, organ enlargement or abnormal fluid accumulation.
Abdominal ultrasound. This test may be recommended, particularly if there is a suspicion that your pet is pregnant or that she might have an underlying disorder.
Blood work. Your veterinarian may recommend other diagnostic tests on a case-by-case basis, including a complete blood count, biochemistry profile to assess liver and kidney function as well as other parameters, a urinalysis and a thyroid level.
Treatments for pseudocyesis may include the following:
Most pets will come out of the false pregnancy in two to three weeks without difficulty and without intervention. Spaying (ovariohysterectomy) will not eliminate clinical signs but can prevent reoccurrence of false pregnancy in the future. Spaying typically is not recommended during false pregnancy but can be done after the false pregnancy signs have resolved and your pet is no longer in heat. Other treatment is generally not recommended unless the symptoms are extremely prolonged or pronounced.
Do not stimulate the mammary glands. Stimulation may increase swelling and milk production and increase the likelihood of problems such as inflammation of the mammary glands.
Some veterinarians suggest decreasing food intake as this may reduce milk production. Other veterinarians recommend limiting access to water at night, which can also reduce milk production. A drug called Lasix® (furosemide) has also been used to increase urine production, which may decrease milk production.
Sedation has been used in pets when needed.
Drug therapy with Bromocryptine (Parlodel®, Sandox®) is used in some countries to decrease milk production, although it is not approved for use in the United States or Canada. This drug causes abortion in pregnant animals.
Other drugs, such as testosterone and mibolerone (Cheque®) may be considered, but their use can be associated with significant side effects. They are not generally recommended. Discuss their use with your veterinarian.
Home Care and Prevention
Pets that are licking excessively at their mammary glands may need an Elizabethan collar. Do not place compresses on your pet's mammary glands. Continue to monitor her for improvement.
To prevent a recurrent episode of false pregnancy, have your pet spayed. Reoccurrence of false pregnancy without spaying is common.