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How to Tell if a Guinea Pig Is Pregnant: 5 Vet-Approved Methods

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By Nicole Cosgrove

female guinea pig with her babies

Vet approved

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Reviewed & Fact-Checked By

Dr. Karyn Kanowski

BVSc MRCVS (Veterinarian)

The information is current and up-to-date in accordance with the latest veterinarian research.

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Guinea pigs are part of the Cavy Family, within the Order Rodents, and are popular pets. Life in the guinea pig lane moves deceivingly fast when compared to some other species. You might be surprised to learn that guinea pigs can be producing more guinea pigs when they are only 2 to 3 months old!

You may also be disappointed to learn that baby guinea pigs are called pups, not guinea piglets.

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Before You Start

Veterinarians and animal welfare agencies do not recommend owners breeding their guinea pigs due to the difficulty in finding suitable homes for the multiple pups subsequently born, and it also reduces the lifespan of the female.Given the information above, it is therefore vital that you have the sex of your guinea pigs identified accurately, even if they are only babies.

Key Facts:
  • Male guinea pigs (boars) reach sexual maturity as early as 3 weeks old.
  • Female guinea pigs (sows) reach sexual maturity at 4 to 5 weeks old.
  • Guinea pigs are pregnant for 59 to 72 days.
  • Guinea pig litter size can range from one to eight pups (four to five is the average).
  • A female guinea pig can have around five litters per year.
  • A female guinea pig will be able to mate again after just a few hours of giving birth. This should not be allowed in order to provide recuperation and replenishment for the sow.

Unfortunately, in pet stores where many guinea pigs are bought, females have often been housed with other males with neither the male nor the female being neutered. Bringing home a pregnant guinea pig is therefore more common than you may think! Accidents may also happen at home. Whatever the scenario, how can you tell if your guinea pig is pregnant?

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The 5 Methods How to Tell if a Guinea Pig Is Pregnant

There are only a few signs to give you an indication that your female guinea pig is pregnant. For confirmation and approximation on whereabouts they are in the gestation, take your guinea pig to your veterinarian, who will examine them and likely perform tests, such as listening to their abdomen with a stethoscope for extra heartbeats and/or an ultrasound scan to confirm all the details you wish and need to know.

1. Contact With an Intact Male

Males and females should be kept and housed separately until the boar is neutered. It is easier, less complex, and safer to neuter the male rather than the female. However, this procedure cannot be performed on the male until they are around 3 or 4 months old, giving plenty of time for mating to occur.

If you know your female has been around an intact male, there is a higher chance that your female is pregnant, than not.

2. Increased Appetite

A pregnant guinea pig will begin to have a more vivacious appetite. If they are drinking more water, polishing their bowls of food off more quickly, and munching their way through extra treats, pregnancy should be high on your list of explanations for this sudden increase in food and water.

Guinea Pig eating a carrot
Image Credit: enchanted_fairy, Shutterstock

3. Size and Weight

As with any other pregnant animal or human, weight gain is one of the first physical signs of pregnancy. By the end of the term, they will have doubled in weight. This is a gradual process and not immediately apparent, particularly if you are around them all the time. Weighing your guinea pig daily is a good way to check if they are gaining weight, as they will begin consistently adding the grams after only 2 weeks.

Pregnant sows also develop a pear-shaped abdomen, which will become more obvious as the days go on. By around days 50 to 60, their big belly will be unmissable!

If you are seeing these signs in a guinea pig that either
  • is male
  • is female with no access to a male in more than 3 months

you should make an appointment with the vet, as there may be other health conditions causing these physical changes.

4. Feeling Their Abdomen for Pups

In the later stages of pregnancy, wiggling and moving pups can be felt by having a gentle feel of the sides and underside of their abdomen. Care should be taken, as the sow by this stage of gestation might be a little grumpy and dislike being poked and prodded. The pups will feel like lumps and may move around a little.

Caution should always be exercised, as not all lumps felt in the abdomen are pups and could be a different problem, such as cysts, particularly if the lumps aren’t moving when touched. If in doubt, have your veterinarian check any lumps and bumps out.

If they are showing signs of stress having their abdomen palpated, such as growling or trying to get away, do not continue and let your veterinarian perform this activity. Undue stress can cause many unnecessary issues, especially during pregnancy.

guinea pig licking human hand
Image Credit: Lipatova Maryna, Shutterstock

5. Behavioral Changes

Female guinea pigs are often placid and friendly, but behavior can change once they are pregnant, and you may notice they begin to show one or all of the following signs:

  • Less social and interactive
  • Less playful
  • Sleeping more
  • Irritability
  • Dislike been handled

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Guinea pigs reproduce easily and rapidly so separation between the two sexes early on is paramount. Unfortunately, this often doesn’t happen, so it is important to enquire about how your guinea pig was housed before taking her home to avoid any surprises.

Reputable breeders and rescue centers will separate them and likely have the males neutered when at an appropriate age and health. Guinea pigs sought from reputable places will also be in good condition and healthy.

Any suspicions at all surrounding the pregnancy of your pet should be confirmed by your veterinarian who will also advise on ongoing care, alterations needed, and, of course, how to look after the impending baby piggies.

Featured Image Credit: Pernille Westh, Shutterstock

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