If you have a female guinea pig who has recently been in the company of a male, pregnancy is a definite possibility. You might pick up on a few subtle signs of it in her, all the way up until the end. Guinea pig pregnancies generally last for between 63 and 68 days.
Distant, Less Energetic Behavior
If your guinea pig is close to going into labor, you might see a marked change in her temperament, albeit a temporary one. If she seems unusually reluctant to be active and move around, it could indicate that she's as close as one week away from parturition. Not only do pregnant guinea pigs seem a bit more lethargic prior to birthing, they also often behave more distantly. If your pet is usually a jovial ball of fur yet all of a sudden has no interest in even acknowledging you, it could mean that her pups are almost here.
Although nesting is a common behavior in many animals, it isn't characteristic of female guinea pigs, so don't wait around for it. Unlike dogs, for example, expectant guinea pigs don't seek out secluded and safe spots to bring their young into the world. Since they don't nest, that's one less clue that can signify an impending birth. Pregnant guinea pigs in many cases display zero indications at all. Because of this, guessing a delivery date isn't easy.
Keep an Eye on the Boys
Other guinea pigs sometimes act differently around pregnant specimens. If male guinea pigs are in the vicinity, you might see them congregating around a pregnant female just prior to labor. This behavior serves as an attempt not only to soon breed with the female, but also to guard her from danger.
Packing on the Pounds (or Ounces)
Apart from behavioral hints, physical hints can also sometimes be telling. As a sow's due date gets closer and closer, you might see her stomach packing on some significant weight, just as with pregnant women. A substantially larger belly generally signifies that a female guinea pig is on the verge of going into labor. Pregnant females frequently weigh twice as much as they did previously. Weight gain isn't really noticeable during the first month of guinea pig gestation.
If a guinea pig is starting labor, she might make it apparent to you by staying seated and nearly motionless, all the while making a conspicuous hiccup-like action. Contractions might accompany this, too. If your guinea pig is experiencing contractions, she might crouch down and then actually extract a newborn youngster from below her body. Female guinea pigs tend to be extremely self-sufficient when it comes to birthing, although it's always crucial to involve a veterinarian in the process.