Endometritis in Guinea Pigs: Uterine Inflammation in Female Guinea Pigs

Endometritis is inflammation of the endometrium, the inner lining of the uterus. In female guinea pigs, this problem is uncommon compared with ovarian cysts, but it can be serious when it happens. The uterus may become irritated, infected, or filled with abnormal fluid. In some guinea pigs, endometritis overlaps with pyometra, a more severe uterine infection involving pus.

Because guinea pigs are prey animals, they often hide illness until they feel quite sick. A guinea pig with uterine inflammation may show only subtle changes at first, like eating a little less, losing weight, or having a small amount of discharge. As infection progresses, pain, dehydration, and gastrointestinal stasis can follow.

This condition is seen only in intact females that still have a uterus. It may be linked to reproductive tract changes such as cystic endometrial hyperplasia, retained material after pregnancy, or bacterial infection ascending through the reproductive tract. Merck notes that reproductive disease in guinea pigs can include cystic endometrial hyperplasia, mucometra, and endometritis, especially alongside ovarian disease.

The good news is that there are several care paths. Some guinea pigs need stabilization and imaging first, while others do best with surgery to remove the uterus and ovaries. Your vet can help match the plan to your guinea pig's age, stability, breeding history, and overall health.

Endometritis usually develops when bacteria enter the uterus and the uterine lining becomes inflamed. This may happen after breeding, after giving birth, or when retained placental or fetal material remains in the uterus. In other cases, the uterus becomes abnormal first and then infection follows.

One important risk factor is cystic endometrial hyperplasia, a thickened and cystic uterine lining that can trap fluid and make infection more likely. Merck lists cystic endometrial hyperplasia, mucometra, and endometritis among reproductive tract disorders seen in guinea pigs, and these changes may occur with ovarian disease.

Hormonal influences may also matter. Guinea pigs with ovarian cysts can have reproductive hormone disturbances, and those changes may contribute to uterine lining disease over time. Older intact females and guinea pigs with a history of breeding problems may be at higher risk.

Poor general health does not directly cause endometritis, but stress, delayed veterinary care, and missed early signs can allow a mild uterine problem to become a more dangerous infection. That is why any discharge, appetite drop, or post-pregnancy concern deserves prompt attention from your vet.

Your vet will start with a careful history and physical exam. They will ask about age, whether your guinea pig is intact, any recent pregnancy or breeding, appetite changes, weight loss, and whether you have seen discharge or blood spotting.

Imaging is often the most helpful next step. Abdominal ultrasound can show an enlarged uterus, fluid within the uterine horns, thickened uterine walls, or other reproductive tract changes. Radiographs may also help identify an enlarged soft-tissue structure in the abdomen and rule out pregnancy, bladder stones, or other causes of swelling.

If discharge is present, your vet may recommend cytology or bacterial culture to help guide antibiotic choices. Bloodwork can be useful in sicker guinea pigs to assess hydration, inflammation, organ function, and anesthesia risk before surgery. Not every guinea pig needs every test, especially if finances are tight, but imaging is often the key step that changes the treatment plan.

Because signs can overlap with ovarian cysts, pregnancy, urinary tract disease, and pyometra, diagnosis should not rely on symptoms alone. Your vet will use the exam, imaging, and your guinea pig's stability to decide whether medical management, surgery, or urgent hospitalization makes the most sense.

The most reliable prevention is to discuss elective spaying with your vet before reproductive disease develops. Spaying removes the uterus and ovaries, which prevents endometritis, pyometra, and future uterine disease. It is not the right choice for every guinea pig, but it is worth a conversation, especially for intact females with ovarian cysts or repeated reproductive concerns.

If your guinea pig remains intact, regular wellness visits matter. Guinea pigs hide illness well, and early changes like mild discharge, weight loss, or reduced appetite are easy to miss. Weighing your guinea pig at home every week can help you catch subtle decline sooner.

Breeding management also matters. Prompt veterinary care after difficult labor, stillbirth, retained material, or abnormal postpartum discharge may reduce the risk of a uterine infection becoming severe. Any intact female with discharge, belly enlargement, or appetite loss should be checked quickly.

Good daily husbandry supports overall health even though it cannot fully prevent uterine disease. Keep the enclosure clean and dry, provide unlimited grass hay, fresh water, a balanced guinea pig diet with vitamin C, and minimize stress. Healthy baseline care makes it easier for your guinea pig to recover if a reproductive problem does occur.