Phantom pregnancy in dogs

Emma Stenhouse
21 April 2022 - 6 min read
Dog with phantom pregnancy

You’ve probably heard the term phantom pregnancy before. But do you know what it is and how it happens?

Vet Sophie Bell explains more about this condition in dogs, including some telltale signs to watch out for.

Discover how to help support your dog during a phantom pregnancy, and why it’s important to avoid spaying her during this time.

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What’s phantom pregnancy and what are the signs?

“A phantom pregnancy occurs when hormone levels in an unspayed female dog ‘tricks’ her body into thinking she’s pregnant when she’s really not” says Sophie.

This can cause physical and behavioural changes that owners may notice in their dogs.

Phantom pregnancies are also sometimes called a false pregnancy, or pseudopregnancy.  

Sophie explains the three different stages of a dog’s season and how these can affect the development of a phantom pregnancy:

  1. Pro-oestrus. The hormone oestrogen rises, causing a swollen vulva and a bloody discharge. This stage usually lasts nine days on average, but can range from three to 21 days.
  2. Oestrus. Ovulation occurs within this stage, when a female dog is considered ‘in season’. She’ll be attractive to male dogs and may actively be looking for a mate when you’re out and about. At this stage, the vulva is still swollen but any bloody discharge will have stopped. After ovulation, oestrogen declines and progesterone starts to rise. Again, this stage usually lasts nine days but can have a range of three to 21 days.
  3. Metoestrus or dioestrus. This is the most important stage when it comes to a phantom pregnancy developing. Here, progesterone levels fall and prolactin levels increase, with a peak at 40 to 60 days after ovulation. Prolactin will decline if there’s no viable pregnancy, but this is also the hormone responsible for the development of a phantom pregnancy.   

“It’s important to note that all female un-spayed dogs will suffer from a degree of phantom pregnancy as their prolactin levels rise” says Sophie.

When and how long a phantom pregnancy lasts depends on each dog’s cycle length and how long the prolactin remains in her system, but around three to four weeks is normal. Phantom pregnancies tend to develop within three to 14 weeks after oestrus.

“If a female dog shows no outward clinical signs, we class them as a covert phantom pregnancy. Females who show obvious clinical signs are classed as an overt phantom pregnancy,” says Sophie.

Common signs of phantom pregnancy include:

  • Enlarged mammary glands
  • Weight gain
  • Decreased appetite

Less common signs include:

An enlarged abdomen can make owners think their dog may be pregnant, but if you know she hasn’t been in contact with any male dogs, a phantom pregnancy is more likely.

You might even notice her nipples start to leak milk. “This is most likely from the furthest back nipples, nearest the tail,” says Sophie. “If you squeeze the nipples firmly and there’s any sign of either milk or a discharge that doesn’t look like milk, this is indicative of a phantom pregnancy” says Sophie.

Behavioural signs to watch out for can include:

  • Restlessness
  • Nesting
  • ‘Mothering’ of soft toys or bedding

Female dogs may also carry out destructive behaviours like digging. While some dogs may become more lethargic, others will become more active.

Your dog may also display anxiety, reactivity, and even aggression. Be aware that the strong instinct to mother items, or guard her bed, can make some dogs reactive and more prone to growl or bite.

Some breeds including Pointers, Basset Hounds, Afghan Hounds, Boxers, Dalmatians, and Dachshunds are more likely to suffer from phantom pregnancies.

How can I tell if my dog is pregnant or having a phantom pregnancy?

During the early stages of pregnancy, it can be hard to tell if your dog is actually pregnant or not, especially if she’s been in contact with male dogs. The symptoms of a phantom pregnancy tend to last around three to four weeks.

Your vet will probably confirm a pregnancy using ultrasound or palpation, but these aren’t accurate until after the 25th day of term. By this stage, the symptoms of a phantom pregnancy have usually disappeared.

If you’d like your vet to confirm a pregnancy before the 25th day of term, ask them to do a blood test. 

What should I do if my dog’s having a phantom pregnancy?

Your first step should be to book your dog in for an examination with your vet. Their diagnosis will be based on the clinical signs, combined with details about when your dog was last in season. 

“Depending on the severity of your dog’s symptoms, your vet will likely recommend either a conservative approach, or medical treatment” says Sophie.

Conservative treatment

A conservative approach involves waiting for your dog’s symptoms to subside, which usually takes around three to four weeks. During this time, there are things you can do to help speed this up, including:

  • Removing toys she‘s mothering
  • Using a buster collar to prevent her licking her mammary glands
  • Temporarily cutting down her meals to help dry up the milk supply 

You should always discuss these treatment options with your vet first.

Medical treatment

Medical treatment involves using the drug cabergoline, which inhibits the production of prolactin.

The cost of treatment will depend on the size of your dog, how many treatments they need, plus any consultation fees. For a large dog, this could be up to £400, although this may be covered by your pet insurance

In 2021 we saw 321 claims for phantom pregnancies in dogs with an average claim cost of £170.34. If it’s a repeated problem for your dog and causes other health problems like pyometra, the cost will be much higher so you might want to consider spaying.

“While medical treatment may lead to some side effects like anorexia and vomiting, these usually settle down within a couple of days” says Sophie.

“Don’t risk leaving your dog without any treatment” says Sophie. “This can cause mastitis if she’s producing a lot of milk with no puppies to feed. Mastitis is painful but also causes inflammation which can lead to infections.

“Your dog may also lose condition as she burns calories to produce milk. She could also become aggressive and could bite through no fault of her own. In some cases, this may lead to the dog being euthanised” says Sophie. 

Spaying and phantom pregnancy

During a phantom pregnancy, it’s very important that you don’t spay your dog. That’s because her body will then remain in this state of phantom pregnancy, accompanied by the physical and behavioural signs outlined above. This is known as persistent phantom pregnancy. 

What is persistent phantom pregnancy?

If your dog is spayed while she’s suffering from a phantom pregnancy, her symptoms will often continue even after she’s been spayed. This can be a problem for dogs suffering from covert phantom pregnancies, as they won’t have been showing any signs. 

After spaying, they may start to show obvious signs of a phantom pregnancy. Sophie says that “these symptoms won’t go away on their own, and it’s important to seek treatment for your dog.”

“These signs can include anxiety and aggressive tendencies, which can even lead to otherwise healthy dogs being euthanised as their behaviour doesn’t improve over time” says Sophie.

The good news is that treatment with cabergoline should resolve this behaviour. 

To avoid spaying your dog during a covert phantom pregnancy, Sophie advises “making sure you note the date of your dog’s cycle when she first starts bleeding, and when she stops. Make a note of when her vulva has shrunk back to its normal size, plus any behavioural changes.” 

Your vet will check for obvious signs like mammary enlargement, but the more information you can provide, the better. If your vet suspects your dog is suffering from a covert phantom pregnancy, they may delay the spay date.  

If you suspect your dog was spayed during a phantom pregnancy, you should focus on preparing to support her if she shows signs of aggression. Speak to your vet about the possibility of medical treatment which could resolve the issue. An animal behaviourist may also be able to help. 

Can cats have phantom pregnancies?

Cats can have phantom pregnancies, but they’re a lot less common than in dogs. In fact, if your female cat is unspayed and spends time outdoors, it’s far more likely that she really is pregnant!

During a phantom pregnancy, cats can show the same signs as we’ve covered above for dogs.

If you do suspect your unspayed female cat is suffering from a phantom pregnancy, it’s always best to speak to your vet for advice.

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