False pregnancy is most commonly seen in female dogs (although cats may rarely be affected). Hormone changes after a ‘season’ or heat convince her and her body that she is pregnant. It is sometimes called phantom pregnancy or pseudopregnancy. The hormone changes that cause false pregnancy are normal in the dog but sometimes the symptoms get out of hand and are distressing for the dog and her owners. 

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Is phantom pregnancy in dogs common?

50-75% of unspayed female dogs will experience a noticeable false pregnancy during their lifetime. It is thought by some biologists that it evolved as a useful condition for wolf packs and continues in the domestic dog. If a number of aunties in the pack experience false pregnancy and produce milk, any wolf cubs in the pack would be more likely to survive. 

False pregnancies do occur in other mammals. For example, in rabbits, they can occur in stressful situations. The doe may be seen to nest obsessively and lose weight. They are thankfully less common in cats and humans. 

What are the symptoms of a false pregnancy?

A dog can display a range of symptoms. These can be grouped together in physical changes and uncharacteristic behaviours.

Physical Signs

The signs of false pregnancy are usually seen 4-8 weeks after a season. Researchers from Glasgow vet school (Root and others) published a helpful review from the experiences of almost 400 vets in 2018. They found that the most common finding was enlargement of the mammary glands (breasts). Clear fluid brownish fluid or milk may be produced by the swollen glands. 

Most female dogs who show symptoms will be restless and anxious, unsettled by the change in hormones. They often eat less and are less keen to interact with people and go for walks. Rarely, they vomit and their abdomens appear swollen. 

Behavioural indicators

Along with these physical changes, behavioural changes are common. Usually, the dog will act as if she has had pups. She may collect soft toys, cushions, shoes, socks or other objects from around the house and take them to her bed or a chosen corner. She will then mother them: hide them, guard them and lick them. 

At this time, she may become aggressive and protective of her nest and imaginary babies. It is important not to misunderstand her at this point. She honestly believes these are pups so it is best to distract her with walks and cuddles when possible, rather than try to encourage her to give them up. She is likely to become uncharacteristically aggressive if she feels the safety of her pups is in question. Even the sweetest family pet can growl and even bite in this situation. 

It is believed by some behaviourists that if a dog is spayed when she is experiencing false pregnancy, she may behave more aggressively. This is why vets tend to advise spaying a reasonable time after a season.

What do you do about a false pregnancy?

First, consider carefully whether this is a false pregnancy. Is there any chance that she was mated while in season? In these instances, visit your vet for an ultrasound examination to confirm whether this is a false pregnancy or just a surprise pregnancy. 

Swollen mammary glands and milk production can make the bitch lick herself until she is sore. This can lead to more milk production and sometimes infection. So, it is important to stop her if she is licking excessively. An Elizabethan collar, inflatable collar, romper suit or T-shirt can be used to stop her licking. 

Some sources will suggest restricting food and water to make her milk dry up. There could cause far more problems and is not advisable. Warm compresses on her abdomen will encourage milk production rather than give her relief.

This is a normal condition and will usually pass in 1-2 weeks.  

When to see a vet?

If your dog seems unwell, becomes lethargic or she isn’t eating then visit your vet.  Unfortunately, a womb infection or pyometra can also occur after a season and this is a dangerous condition. She may have a vaginal discharge and vomit with a pyometra or just seem very unwell. Mastitis, an infection of the mammary glands, can also make her ill. 

If signs of false pregnancy go on for more than 2-3 weeks or she is uncomfortable with her mammary swelling then medication can be used to reverse the hormone changes and resolve the false pregnancy.    

Some dogs have marked false pregnancies after every season, others are very distressed by marked symptoms. Spaying (ovariohysterectomy or ovariectomy) offers a permanent solution to the condition, as there are no further seasons. The decision to spay also protects her against unwanted pregnancies, womb infections and can be protective against mammary cancer.

As we have seen, false pregnancy is usually a mild, physiologically normal state but in some dogs it causes distress and discomfort. Fortunately, the signs are easily treated when recognised. 

Share your experiences with false pregnancies and ask any questions on the topic below.

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