Guinea pigs have come a long way from their wild burrowing ancestors. They have adapted tremendously to living with humans. However, the reproductive system on the female guinea pig (or sow) has yet to catch up with the pace of modern guinea pig life.
Nature designed guinea pig sows to become pregnant when they are three to six months old. For most mammals, it does not matter when the female gets pregnant (as long as she can still come into season). But with guinea pigs, the situation is different. If the sow gets pregnant for the first time after seven months of age, she will most likely develop dystocia. Sounds scary, doesn’t it?
What Is Dystocia?
Dystocia sounds scary because it is scary. This means the pelvis has fused together. This means there is no room for baby guinea pigs (known as pups) to come out of Mom, unless they are very small babies. Dystocia is potentially lethal for the sow as well as the pups.
When a sow gets pregnant young enough, from 3 – 6 months of age, the bones in the pelvis are flexible. Getting pregnant pushes them apart and gets her ready to pop out pups for the rest of her fertile life. If time passes and the pelvic area has fused together, then getting pregnant can be a death sentence for the sow as well as the pups.
Not all sows pelvic bones begin to fuse when they are six months old, but a majority do. Don’t take a chance – don’t breed your guinea pig if you have pet guinea pigs.
However, accidents of the biological kind certainly happen whenever guinea pigs are concerned. It can be very difficult to sex baby guinea pigs in order to keep the sexes separate. Often, sows are misidentified and get stuck in with the boars. Or, the guinea pig could be sold from a pet shop already pregnant. The Fates seem to conspire to get guinea pigs pregnant at the most inconvenient times.
As soon as you suspect that your older sow is pregnant, get her to the vet for pregnancy tests. Your sow is going to have to have return to the vet’s – either for an abortion now or Cesarean section at the normal birth time. The odds of both sow and pups surviving the Cesarean section are good, but listen to your vet and your instincts based on your observations of your guinea pig. Each situation will be different.
If you do not know the age of your pregnant sow, then you should be prepared for the possibility of dystocia. If she goes into labor and nothing appears except blood and fluids for over half an hour, get her to an emergency veterinarian for a Caesarian section, done under general anesthesia.
Amazingly, most guinea pig Moms can immediately nurse their babies soon after the operation.
The Proper Care of Guinea Pigs. Peter Gurney. TFH: 1992.
Guinea Pigs. Audrey Pavia, et al. Bow Tie Press; 2005.
Pet Place: “Guinea Pig Dystocia and Pregnancy Toxemia.” http://www.petplace.com/small-mammals/guinea-pig-dystocia-and-pregnancy-toxemia/page1.aspx
Guinea Lynx. “Reproduction and Breeding.”