Merck Manual

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Professional Version

Metritis in Small Animals


Clare M. Scully

, MA, DVM, MS, DACT, Louisiana State University, Department of Veterinary Clinical Sciences

Reviewed/Revised Jul 2023

Metritis is defined as a uterine infection. Inflammation of the endometrium and myometrium characterized by postpartum vaginal discharge is a classic sign of metritis. However, due to the serious nature of other diseases that cause postpartum vaginal discharge it must be differentiated from other conditions. These include normal postpartum lochia, subinvolution of placental sites (SIPS), vaginal or uterine trauma and pyometra.

Normal lochia seen after whelping should resolve within three weeks of parturition. The amount, odor, consistency, and color can act as an indication of a problem. For example, if the amount increases and the odor is fetid, further examination is warranted. Some causes of metritis include obstetric manipulation, necrotic tissue in the uterus, and fetal or placental retention.

Clinical Signs of Metritis in Small Animals

Clinical signs of metritis include anorexia, lethargy, vomiting, decreased maternal instincts, fever, and decreased or absent milk production.

Diagnosis of Metritis in Small Animals

History and physical examination should aid in ruling out other diseases that cause postpartum vaginal discharge. Clinical signs can aid in distinguishing metritis from SIPS; bitches with SIPS show no clinical signs of systemic disease.

Metritis is diagnosed by cytologic evaluation and microbial culture of the vulvar discharge.

In addition, further diagnostic testing can include CBC, serum biochemical analysis, urinalysis, and diagnostic imaging.

Changes in clinicopathologic parameters usually reflect septicemia, inflammatory reactions, and endotoxemia. This can be represented by either increased or decreased WBC count, with or without anemia, increased or decreased protein concentration, signs of dehydration, or elevations in kidney and liver enzyme activity.

Treatment of Metritis in Small Animals

Treatment of metritis depends on severity of disease.

In a simple case, antimicrobial treatment based on microbial culture and antimicrobial susceptibility testing may be enough.

If systemic disease is present, then fluid therapy and supportive care may be necessary to stabilize the patient's condition.

If needed, evacuation of the uterus can be accomplished with oxytocin and prostaglandins. Prostaglandin PGF2a (0.1–0.25 mg/kg, SC, for 2–3 days) or oxytocin (5–20 U in bitches, 2–5 U in queens, IM) may help evacuate the uterine contents. With prostaglandins, adverse effects include abdominal pain, tachypnea, hypersalivation, vomiting, and diarrhea. Due to nature of the adverse effects, it is encouraged to treat the patient in the hospital to manage any discomfort.

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