Do Female Guinea Pigs Have Periods?

When I first had female guinea pigs (sows), I didn't have the Internet and did not have a public library nearby. I learned all I could from talking to my vet and from reading the few books available in my local pet stores.

One of my sows was sitting in a crouched position with wide eyes. I picked her up and noticed a dollop of dark blood came out and onto my hand. I put her in a solitary cage for a day and she picked up, so I thought she was fine and put her back with the other sows. I thought she'd just had a bad period.

Oh, idiot me. Female guinea pigs do not pass blood during their estrous or season. I should've gotten my guinea pig to a vet and regret that I did not. Although my guinea pig seemed none the worse for her experience, it could have been a lot worse.

Causes of Bleeding

So if my sow didn't have her period, what happened? According to The Guinea Pig Handbook (Barron's; 2003) author, veterinarian Sharon L. Vanderlip, DVM, my guinea pig most likely had a urinary tract infection. This can cause not only blood but lack of appetite, fatigue and pain when urinating. My pet was hunched in an unusual position when I noticed her. Most likely she was having difficulty urinating.

Another cause of bleeding in female guinea pigs is one or more bladder stones in the urinary tract system. These stones or calculi are made of calcium carbonate. Some stones are quite soft. Stones can be deadly in male guinea pigs, or boars, since a stone can block the urethra and make the boar unable to urinate.

Miscarriage

My sow had never been bred, so I know she did not have this other cause of bleeding in female guinea pigs - a miscarriage. Veterinarians call it "abortion" but this is a spontaneous expulsion of one or more fetuses from a litter. This can be caused by a bacterial infection, a virus or trauma which leads to shock. Guinea pigs recover quickly from a miscarriage.

It can be very frightening, though. Blood comes out of the sow and then gets on her face as she cleans herself up. She also eats the dead pups. In the wild, leaving a dead pup nearby was dangerous. Predators could smell it and soon find the colony of wild guinea pigs. Although guinea pigs have been domesticated since the time of the Incan empire, they have not lost this instinct.

In Conclusion

If your female guinea pig ever passes blood in her urine, has blood coming out of her vagina or has blood smeared on her bottom, she needs medical attention as soon as possible.

References

The Guinea Pig Handbook. Sharon L. Vanderlip, DVM. Barron's; 2005.

Guinea Lynx. "Bladder Stones." http://www.guinealynx.info/stones.html

LA Guinea Pig Rescue. "Guinea Pig Care: A." http://laguineapigrescue.com/?page_id=77