Metritis / Uterine infection

Metritis is an infection and inflammation of the uterus that occurs primarily in postpartum queens during the period following delivery. This serious condition develops when bacteria invade the uterine lining, which is particularly vulnerable following parturition due to the changes associated with pregnancy and birth. Metritis typically manifests within the first week after delivery, though it may develop up to two weeks postpartum. The condition represents a significant threat to both the queen's health and, indirectly, to her nursing kittens who depend on her care. Metritis requires prompt veterinary intervention to prevent potentially life-threatening complications.

The development of metritis is closely linked to events occurring during and after parturition. The cervix remains dilated for a period following birth, allowing potential bacterial entry into the normally sterile uterine environment. The uterine lining, having supported pregnancy, undergoes involution and repair that creates tissue susceptible to infection. Retained placental tissue, fetal membranes, or fetuses provide material that supports bacterial growth. Obstetrical manipulation during difficult deliveries may introduce bacteria or cause trauma that facilitates infection. These factors combine to create a window of vulnerability during which metritis can develop.

The impact of metritis on affected queens ranges from systemic illness of moderate severity to life-threatening sepsis. Infected cats typically become ill rapidly, developing fever, lethargy, and decreased appetite within days of delivery. The toxins produced by bacteria within the uterus can spread throughout the body, causing systemic inflammatory response. Affected queens may be unable to care adequately for their newborn kittens, potentially necessitating supplemental care of the litter. Without treatment, metritis can progress to septicemia, peritonitis if uterine rupture occurs, or death. The serious nature of this condition demands immediate veterinary attention.

Metritis is treatable, and most cats recover fully when the condition is identified and treated promptly. Treatment typically involves systemic antibiotic therapy targeted at common uterine pathogens. Supportive care including fluid therapy addresses dehydration and supports organ function. In cases where retained material is present or medical management is inadequate, ovariohysterectomy provides definitive treatment by removing the infected uterus. Most cats treated early in the course of infection make complete recoveries. Understanding the risk factors and signs of metritis enables breeders and owners to seek prompt care when symptoms develop.

Bacterial infection is the direct cause of metritis, with various organisms capable of causing uterine infection. Escherichia coli is the most commonly isolated pathogen from cats with metritis, though Streptococcus, Staphylococcus, Proteus, and other bacteria may also be involved. These organisms are commonly present in the environment and on mucosal surfaces, becoming pathogenic when they gain access to the normally sterile uterine cavity. Anaerobic bacteria may also contribute to infection, particularly in severe cases. Mixed infections involving multiple bacterial species occur frequently, reflecting the opportunistic nature of uterine colonization after delivery.

Retained reproductive material provides the most significant predisposing factor for metritis development. Retained placental tissue that fails to pass following delivery creates foreign material within the uterus that supports bacterial colonization and growth. Retained fetal membranes similarly provide substrate for infection. In rare cases, a retained dead fetus that was not delivered creates severe risk for infection. The decaying tissue releases nutrients that sustain bacterial multiplication and creates an environment in which infection flourishes. Even small amounts of retained material can serve as a nidus for infection.

Dystocia, or difficult labor, significantly increases the risk of developing metritis. Prolonged labor exhausts the queen and compromises uterine function. Obstetrical intervention, while often necessary, may introduce bacteria into the reproductive tract, particularly if instruments or hands enter the vaginal canal or uterus. Trauma to the uterine lining from manipulation creates damaged tissue susceptible to infection. Cesarean section, though performed under sterile conditions, involves opening the uterus and carries inherent infection risk. The more complicated the delivery, the greater the likelihood of subsequent metritis.

Anatomical and physiological factors during the postpartum period create vulnerability to infection. The cervix remains somewhat dilated for several days following delivery, providing a route for ascending bacterial infection from the vagina. The uterine lining is regenerating after placental detachment, creating a surface not yet fully protected by normal mucosa. Lochia, the normal postpartum vaginal discharge, may serve as a medium for bacterial growth if drainage is impaired. Normal uterine involution, the process by which the uterus returns to its pre-pregnancy size, can be disrupted by infection, creating a cycle of continued susceptibility.

Environmental factors contribute to metritis risk through their influence on bacterial exposure. Unsanitary birthing conditions increase the load of bacteria present in the environment. Contaminated bedding in the queening area can harbor pathogenic organisms. Crowded conditions or multiple cats sharing birthing areas may increase bacterial transmission. Poor hygiene practices during or after delivery can introduce bacteria. Temperature extremes or stress during the peripartum period may compromise the queen's immune function, reducing her ability to combat bacterial invasion.

Early warning signs of metritis typically appear within the first few days following delivery, though symptoms may develop up to two weeks postpartum. Initial signs are often subtle and may be attributed to normal postpartum fatigue. The queen may seem slightly more tired than expected, spending excessive time resting rather than actively caring for kittens. Appetite may decrease modestly before more obvious illness develops. Low-grade fever may be present even before other symptoms become apparent. Attentive observation during the postpartum period is essential for early detection, as queens are normally somewhat subdued after delivery.

The characteristic symptom of metritis is foul-smelling vaginal discharge that persists beyond normal postpartum drainage. Normal lochia following delivery is initially bloody, becoming serous over the first week and diminishing. In metritis, the discharge becomes purulent, appearing thick, cloudy, or containing pus. The distinctive foul odor of infected discharge is often the most noticeable sign to owners. The discharge may appear on bedding, around the vulva, or be noticed during normal cleaning. Dark brown, greenish, or gray discharge is abnormal and should prompt immediate veterinary evaluation.

Systemic illness develops rapidly once infection establishes in the uterus. Fever is common, often exceeding 104°F as the body responds to infection. The queen becomes increasingly lethargic, showing reduced interest in her kittens and her surroundings. Appetite decreases significantly, with complete refusal of food indicating serious illness. Increased thirst may occur due to fever and dehydration. The queen may neglect grooming, appearing unkempt compared to her normal condition. These systemic signs reflect the body's response to bacterial toxins and the developing septicemia.

Behavioral changes reflect both illness and discomfort. Affected queens may neglect their litters, failing to nurse adequately or keep kittens clean. Some queens abandon their kittens entirely, moving away from the nesting area. Restlessness alternating with excessive lethargy may be observed. The queen may vocalize more than normal, indicating discomfort. Abdominal discomfort may cause reluctance to lie in normal nursing positions. If nursing continues, kittens may fail to thrive due to inadequate milk production or illness transmitted through contact with the infected queen.

Progressive symptoms indicate worsening infection requiring emergency intervention. Vomiting and diarrhea may develop as systemic toxemia advances. Abdominal distension or pain on abdominal palpation suggests uterine enlargement or peritonitis. Rapid or labored breathing indicates systemic compromise. Pale or muddy gum color suggests shock or severe anemia. Collapse or inability to stand represents critical illness. Cessation of all vaginal discharge when other symptoms are present may indicate uterine rupture with drainage into the abdomen.

Emergency symptoms requiring immediate veterinary care include high fever persisting despite early treatment, complete cessation of eating and drinking, severe lethargy or collapse, signs of shock including pale gums and weak pulse, abdominal distension or severe pain, bloody or hemorrhagic vaginal discharge, and rapid decline in condition over hours. Any queen that becomes acutely ill within two weeks of delivery should be evaluated urgently for metritis. The condition can progress rapidly from apparent wellness to life-threatening illness, making prompt action essential.

Initial veterinary examination for suspected metritis includes comprehensive assessment of the queen's overall condition and reproductive status. Vital signs are evaluated, with particular attention to temperature elevation indicating infection. The veterinarian will examine the vulva for discharge and may express material from the vaginal canal for assessment. Abdominal palpation evaluates the uterus for enlargement, pain, or abnormal contents. The mammary glands are examined since mastitis may occur concurrently. General body condition, hydration status, and signs of systemic illness are assessed. History regarding the recent delivery, including any complications, is obtained.

Diagnostic testing helps confirm metritis and assess severity. Complete blood count typically reveals elevated white blood cell count indicating infection, though severely ill cats may have paradoxically low counts due to overwhelming sepsis. Blood chemistry evaluates organ function, particularly kidneys and liver that may be affected by toxemia. Vaginal cytology allows examination of cells and bacteria from the reproductive tract. Culture and sensitivity testing of vaginal discharge or uterine contents identifies the causative bacteria and guides antibiotic selection. Blood culture may be indicated in severely ill cats to evaluate for septicemia.

Imaging studies provide valuable information about uterine condition. Abdominal radiographs may reveal an enlarged uterus or suggest retained material. Radiographs can also identify retained fetuses in cases where complete delivery is uncertain. Abdominal ultrasound offers detailed visualization of the uterus, showing wall thickness, fluid content, and any retained material. Ultrasound is particularly useful for differentiating metritis from pyometra and assessing whether medical management is likely to be successful or surgery is needed. Free abdominal fluid on ultrasound may indicate uterine rupture or peritonitis.

Differential diagnosis considers other conditions that may present similarly. Pyometra, infection of the closed uterus typically occurring in older cats or following estrus, shares features with metritis but has different pathophysiology and typically occurs in non-postpartum cats. Subinvolution of placental sites causes prolonged postpartum bleeding without the fever and discharge of metritis. Normal lochia must be distinguished from pathological discharge. Mastitis can occur concurrently or independently and shares some systemic signs. Accurate diagnosis enables appropriate treatment selection and prognosis.

Antibiotic therapy forms the foundation of medical treatment for metritis. Broad-spectrum antibiotics effective against the likely gram-negative and gram-positive organisms are initiated promptly, often before culture results are available given the urgency of treatment. Common choices include amoxicillin-clavulanate, fluoroquinolones, or cephalosporins, sometimes in combination to provide broad coverage. Once culture and sensitivity results are available, antibiotic selection may be refined to target identified pathogens. Antibiotic therapy typically continues for two to three weeks to ensure complete eradication of infection. The choice of antibiotic considers safety during lactation if the queen is nursing.

Supportive care addresses the systemic effects of infection and maintains the queen's condition. Intravenous fluid therapy corrects dehydration, supports circulation, and aids toxin elimination. Severely ill cats may require aggressive fluid resuscitation to address shock. Nutritional support ensures adequate caloric intake, with assisted feeding if the queen is not eating voluntarily. Temperature regulation helps manage fever. Pain management with appropriate analgesics maintains comfort and encourages the queen to eat and care for her kittens. Intensive care hospitalization may be necessary for severely affected cats.

Medications to promote uterine emptying may be used in conjunction with antibiotics. Oxytocin stimulates uterine contractions that help expel infectious material and retained tissue. Prostaglandins have similar effects and also cause cervical relaxation that aids drainage. These medications are used carefully, as their use in cases of closed cervix or uterine fragility could cause complications. The goal is to facilitate natural drainage of infected uterine contents while antibiotics address the bacterial infection.

Surgical treatment through ovariohysterectomy may be necessary in some cases. Surgery is indicated when medical management fails to produce improvement within twenty-four to forty-eight hours, when imaging reveals retained material that will not pass naturally, or when the queen is critically ill and rapid removal of the infection source is needed. Ovariohysterectomy removes the infected uterus entirely, eliminating the source of infection and toxin production. Surgery also prevents future reproductive tract infections in cats not intended for breeding. The decision for surgery weighs the benefits of definitive treatment against surgical risks in an ill patient.

Emergency intervention is required for life-threatening presentations. Cats in septic shock require aggressive stabilization including high-volume fluid resuscitation, broad-spectrum intravenous antibiotics, and cardiovascular support. Peritonitis from uterine rupture necessitates emergency surgery for uterine removal and abdominal lavage. Blood transfusion may be needed if severe anemia has developed. Intensive monitoring including blood pressure, urine output, and cardiovascular parameters guides ongoing care. Despite aggressive treatment, mortality can occur in severely affected cats.

Treatment decisions incorporate multiple factors. The queen's breeding value influences whether attempts are made to preserve the uterus through medical management or surgical removal is performed. Severity of illness affects the urgency of surgery versus trial of medical therapy. Response to initial treatment guides continued management. Cost considerations may influence treatment options, as intensive care and surgery carry significant expense. The goal is restoring the queen to health while making appropriate decisions about continued breeding potential.

The recovery timeline for metritis varies based on severity and treatment approach. Cats with mild metritis treated promptly with antibiotics often show improvement within twenty-four to forty-eight hours, with fever resolving and appetite returning. Complete recovery from uncomplicated cases typically occurs over one to two weeks of antibiotic treatment. Cats requiring surgery face longer recovery due to the additional healing from ovariohysterectomy, typically two to three weeks before returning to normal activity. Severely ill cats that required intensive care may have prolonged recovery periods as they regain strength and condition.

Post-treatment care during recovery requires attention to medication compliance and monitoring for complications. Antibiotic administration must continue for the full prescribed course even after symptoms resolve to ensure complete elimination of infection. Incision care following surgery involves keeping the site clean and preventing the cat from traumatizing the area. Activity restriction after surgery prevents complications. Nutritional support helps rebuild condition lost during illness. Close observation for any signs of recurring infection enables early intervention if needed. Kittens that were separated during the queen's illness may require gradual reintroduction.

Prognostic factors influence expected outcomes. Cats treated early in the course of infection before severe systemic illness develops have excellent prognosis. The absence of complications such as peritonitis or septic shock favors recovery. Response to initial treatment within the first twenty-four to forty-eight hours is a positive indicator. Cats that require surgery generally have good outcomes once the infected uterus is removed, assuming they survive anesthesia and the immediate postoperative period. Factors associated with poorer prognosis include delayed treatment, uterine rupture, septic shock, and failure to respond to therapy.

Long-term outlook following recovery from metritis depends on treatment type. Cats that recovered with medical management and retained their uterus may breed again, though careful monitoring during subsequent pregnancies is advised due to potential uterine scarring or increased susceptibility to recurrence. Some veterinarians recommend avoiding breeding for at least one or two estrus cycles following metritis to allow complete uterine healing. Cats that underwent ovariohysterectomy are obviously unable to breed but typically have no long-term health consequences from the surgery or preceding infection. Overall, most cats that survive metritis return to normal health.

Primary prevention of metritis focuses on minimizing risk factors associated with delivery and the postpartum period. Ensuring queens are in optimal health before breeding supports immune function and uncomplicated pregnancy. Appropriate veterinary monitoring during pregnancy identifies potential problems early. Having a clean, prepared queening area ready before delivery reduces environmental bacterial exposure. Observing the delivery process when possible allows detection of prolonged labor or dystocia requiring intervention. Counting placentas to match the number of kittens helps ensure complete placental passage.

Environmental prevention involves maintaining sanitary conditions during and after delivery. The queening area should be warm, dry, and easily cleaned. Bedding should be changed frequently, especially if soiled with blood or discharge. Clean, fresh water should be available at all times. Access by other animals or excessive human visitors should be limited to reduce bacterial introduction. Gloves should be worn if handling the queen's vulvar area or assisting with delivery. Any instruments or materials used during delivery must be sterile.

Appropriate management of delivery complications reduces metritis risk. Dystocia should be addressed promptly with veterinary assistance to minimize trauma and contamination. If cesarean section is necessary, sterile surgical technique and appropriate perioperative antibiotics reduce infection risk. Retained placentas should be addressed rather than left to pass naturally, as they provide substrate for infection. If manual assistance is required during delivery, proper technique and hygiene are essential. Post-delivery oxytocin administration may be recommended by veterinarians to ensure complete uterine emptying.

Routine health maintenance supports the queen's ability to resist infection. Complete vaccination prior to breeding prevents diseases that could compromise immune function. Parasite control ensures the queen is not stressed by parasitic burden. Good nutrition throughout pregnancy supports immune function and overall health. Avoiding excessive stress during pregnancy and delivery helps maintain normal physiological function. Breeding only cats in excellent health and body condition reduces complications.

Early intervention when warning signs appear prevents progression to severe metritis. Monitoring postpartum discharge and the queen's behavior for the first two weeks after delivery enables early detection of abnormalities. Any foul-smelling discharge, fever, or signs of illness warrant immediate veterinary contact. Early treatment before infection becomes severe results in better outcomes and simpler treatment. Educating breeders and owners about normal versus abnormal postpartum signs empowers them to seek appropriate care.

Daily management of a cat recovering from metritis requires attention to medication administration, monitoring, and supportive care. Antibiotics must be given as prescribed, typically twice daily, for the full duration of treatment. The queen's temperature can be monitored at home if she tolerates it, with any fever recurrence reported to the veterinarian. Appetite and water intake should be observed and encouraged with palatable foods. The vulvar area should be kept clean, gently wiping away any discharge. Activity should be limited for cats recovering from surgery, while medically managed cats may gradually return to normal activity as they improve.

Home environment during recovery should support the queen's comfort and healing. A quiet, clean space away from household activity and other pets allows rest. Bedding should be soft, warm, and easily laundered. If the queen is caring for kittens, the nesting area should be maintained with clean, dry bedding. Food and water should be easily accessible without requiring jumping or climbing, especially after surgery. The temperature should be comfortable, as cats recovering from illness may have difficulty regulating body temperature. Litter boxes should be easily accessible with low sides if abdominal surgery was performed.

Decisions about kitten care during and after the queen's recovery require careful consideration. If the queen was too ill to nurse during treatment, kittens may have been supplementally fed or temporarily fostered. As the queen recovers, gradual reintroduction to nursing may be possible once she is clinically stable and on appropriate antibiotics. Kittens should be monitored for adequate weight gain and any signs of illness. Some antibiotics are secreted in milk and may affect kittens, so veterinary guidance on nursing during treatment is important. If the queen underwent ovariohysterectomy and cannot nurse, orphan care of kittens continues until weaning.

Ongoing monitoring throughout recovery detects complications or inadequate response to treatment. Daily observation of the queen's activity level, appetite, and attitude provides information about recovery progress. Vaginal discharge should gradually diminish and should not become foul-smelling or increase after initial improvement. Any return of fever, lethargy, or appetite loss requires prompt veterinary contact. Surgical incisions should be monitored for swelling, discharge, or opening. Follow-up veterinary appointments allow assessment of recovery and determination of when antibiotics can be discontinued.

Support resources for owners managing a cat with metritis include veterinary guidance and educational materials. The treating veterinarian and veterinary nurses can answer questions and provide reassurance during the recovery period. Breeders dealing with metritis may seek advice from breeder mentors or breed clubs, though veterinary recommendations should take precedence. Financial assistance programs may be available for emergency treatment costs. Managing a recovering queen while potentially caring for orphaned kittens is demanding, and seeking help from family or friends can reduce caregiver burden.

Metritis can affect any female cat that has given birth, with no specific breed demonstrating significant genetic predisposition to the condition. The development of metritis is determined primarily by circumstances surrounding parturition rather than breed-related factors. All queens, whether purebred or mixed-breed, face similar risk during the postpartum period. The condition has been documented across all cat breeds and types. Breed does not appear to influence the severity of metritis, response to treatment, or likelihood of complications.

Certain factors that may vary between breeds or breeding situations can indirectly influence metritis occurrence. Brachycephalic breeds such as Persian and Himalayan cats have higher rates of dystocia due to kitten skull conformation, and dystocia increases metritis risk. Breeds with naturally large kittens or breeds where breeding practices result in large kittens may have more difficult deliveries. Breeds commonly bred through planned matings and managed queening may have more veterinary intervention during delivery, which carries both benefits and risks. However, these associations are indirect and relate to birth circumstances rather than inherent breed susceptibility to uterine infection.

Screening and prevention recommendations apply uniformly across all breeds. All queens should receive appropriate prenatal care and veterinary monitoring of pregnancy. Prepared queening areas with attention to hygiene benefit cats of all breeds. Monitoring during and after delivery enables early detection of complications regardless of breed. If dystocia occurs, prompt appropriate intervention reduces metritis risk. Education of breeders about postpartum warning signs applies to all breeding programs. There are no breed-specific tests or screening recommendations for metritis, as prevention relies on management practices rather than identifying genetic susceptibility.

Pyometra, infection of the closed uterus, shares features with metritis but represents a distinct condition. While metritis occurs in the postpartum period with an open cervix allowing drainage, pyometra typically develops in non-pregnant cats during diestrus when the cervix is closed. Pyometra causes accumulation of pus within the uterus, often with dramatic uterine distension. Both conditions cause systemic illness from bacterial toxins, but their timing, predisposing factors, and sometimes treatment considerations differ. Pyometra almost always requires ovariohysterectomy, while metritis may sometimes be managed medically. Understanding the relationship between these conditions highlights the vulnerability of the feline uterus to infection.

Mastitis, infection of the mammary glands, commonly occurs during the same postpartum period as metritis and may develop concurrently. Both conditions affect nursing queens and can compromise care of kittens. A queen with both metritis and mastitis faces compounded illness requiring treatment of both infections. The shared risk factors of the postpartum period, including stress, immune demands of lactation, and environmental bacteria, explain the potential for concurrent development. Thorough examination of cats presenting with postpartum illness should evaluate both the uterus and mammary glands.

Complications of metritis include serious conditions resulting from progression or spread of infection. Septicemia develops when bacteria or their toxins enter the bloodstream, causing systemic inflammatory response and potentially affecting multiple organs. Peritonitis occurs if the infected uterus ruptures, spilling contaminated material into the abdominal cavity and creating a surgical emergency. Endotoxic shock results from overwhelming response to bacterial toxins. Chronic endometritis may develop if acute infection is incompletely resolved, potentially affecting future fertility. Recognition of the potential for these complications underscores the importance of prompt, aggressive treatment of metritis.