Retained Placenta

Retained placenta represents a post-foaling emergency requiring rapid recognition and treatment, occurring when the placenta (afterbirth) fails to deliver normally within a few hours after foal birth. Normal mares deliver the foal and typically pass the placenta within 30 minutes to 3 hours after foaling. When the placenta hasn't delivered by 3 hours post-foaling, retained placenta should be suspected and veterinary help summoned immediately. Unlike some post-foaling complications requiring judgment about urgency, retained placenta demands urgent intervention regardless of how normal the mare otherwise appears.

Retained placenta becomes life-threatening as it sits inside the mare for hours because of several complications that develop. The retained placenta creates inflammation within the uterus, which can develop into severe infection. The mare loses important nutrients and factors the placenta would normally provide postpartum. Blood loss sometimes continues from the placental attachment site. Severe laminitis sometimes develops secondary to retained placenta toxins affecting the laminae in the hooves. Complications of retained placenta can progress from manageable to catastrophic within hours of delivery.

The emotional and practical impact of retained placenta is significant. A new foal and recovering mare require care and attention, and discovering post-foaling complications creates stress and worry. The need for intensive treatment sometimes requires staying at the farm or going to a referral hospital. Some mares recover completely while others have permanent problems affecting future breeding. Understanding what retained placenta is and how it's managed helps you respond appropriately if it occurs.

Recognition of normal placental delivery helps you identify when problems occur. The normal placenta appears as a large membrane structure sometimes partially inverted, about the size and weight of the foal in some cases. It has distinct fetal and maternal surfaces. Normal delivery happens relatively quickly after foaling—mares that haven't delivered the placenta by 3 hours definitely need veterinary help immediately.

This guide helps you understand normal placental delivery, recognize retained placenta signs, understand why rapid treatment is critical, and manage mares experiencing this complication. You'll learn what treatment involves, potential complications, and realistic expectations about recovery and future breeding.

Retained placenta results from failure of normal placental separation from the uterine wall. Normal separation happens as the foal's weight leaves the uterus, creating pressure changes and hormone shifts triggering placental separation. When separation doesn't occur properly, the placenta remains attached. The specific mechanisms causing separation failure vary and sometimes no obvious cause is identified.

Dystocial (difficult) foalings sometimes result in retained placenta—mares experiencing prolonged labor or difficult deliveries show higher retained placenta risk. Uterine exhaustion from prolonged straining might interfere with normal separation. Foaling complications requiring forceful delivery or manual extraction might damage placental separation mechanisms.

Uterine infections preceding foaling increase retained placenta risk. Placentitis developing before delivery sometimes damages placental tissue preventing normal separation. Mares with chronic uterine infections or history of uterine disease show higher retained placenta risk. Premature placental separation (red bag delivery) creates placental damage affecting normal delivery.

Some mares with history of retained placenta are predisposed to recurrence. If a mare retained placenta at previous foaling, she faces higher risk of retaining again. Understanding this predisposition helps guide extra vigilance in those mares and possibly using preventive strategies.

Advanced maternal age sometimes increases retained placenta risk—older mares might have decreased uterine tone and function affecting placental separation. However, retained placenta occurs in mares of all ages. Younger mares can experience retention as can prime-age mares.

Nutrition and body condition might play roles in retained placenta development. Mares in poor condition or with nutritional deficiencies might have compromised uterine function. However, well-nourished mares also experience retention, suggesting factors beyond nutrition drive most cases.

Twins represent a significant retained placenta risk. When twins are present, foaling complications are common and retained placenta frequently accompanies twin deliveries. Mares carrying twins should be identified prenatally when possible to allow preparation for higher-risk foaling.

The most obvious retained placenta sign is failure to pass the placenta by 3 hours post-foaling. A mare that delivered the foal normally but hasn't passed the afterbirth by 3 hours should be assumed to have retained placenta until proven otherwise. Don't wait for additional signs—3 hours without placental delivery is sufficient indication to call your veterinarian immediately.

The mare might appear relatively normal despite placental retention, showing interest in the foal, standing comfortably, and having normal attitude. This normal appearance can be deceptive—dangerous complications are developing internally even while the mare appears well. Never assume a mare is fine just because she looks normal. The 3-hour rule applies regardless of how well the mare seems.

Some mares show signs of discomfort including mild colic-like behavior, restlessness, or signs of straining. The mare might repeatedly squat as if trying to defecate or further strain to deliver the placenta. Some mares show vaginal bleeding or bloody discharge, though some retained placentas produce no obvious discharge.

Partial placental passage sometimes occurs where some placental tissue passes but pieces remain retained. A mare might pass recognizable placental tissue but not completely, leaving retention. Incomplete placenta is essentially retained placenta requiring treatment. If the mare passes what seems like the entire placenta but you're unsure whether it's complete, your veterinarian can assess.

Fever developing post-foaling, particularly if accompanied by other signs, might indicate retained placenta creating infection. Some mares develop fever within hours of retention, while others maintain normal temperature initially. Temperature elevation alone without retention shouldn't be assumed, but retained placenta is high on the differential for post-foaling fever.

Laminitis signs sometimes develop secondary to retained placenta toxins—the mare might show reluctance to stand, weight-shifting, sensitivity of hooves, or lameness. These signs usually develop hours after foaling when retained placenta has been present for some time. The toxic effects of retained placenta sometimes trigger laminitis before obvious infection develops.

Systemic illness signs might develop over hours including depression, tachycardia (elevated heart rate), tachypnea (elevated respiratory rate), or signs of sepsis and shock as infection develops and becomes systemic.

Diagnosis of retained placenta is straightforward—placental delivery hasn't occurred by 3 hours post-foaling. Your veterinarian might examine the mare's reproductive tract to confirm placenta is within the uterus rather than partially out and caught. Visual confirmation that no placenta is obvious at the vulva and that the mare shows signs of retained placenta confirms the diagnosis.

Treatment must begin immediately without delay. The standard treatment involves manual removal of the placenta through the vagina. With the mare properly positioned and prepared, the veterinarian reaches into the uterus to locate the placental attachment points and gently separate the placenta. Some placentas separate fairly easily with gentle traction, while others require careful work. Care is taken to remove the entire placenta without leaving fragments.

Sedation of the mare is typical during placental removal to keep her calm and standing still while the veterinarian works. The procedure requires careful technique to avoid uterine rupture or excessive hemorrhage. In most cases, careful removal is successful without major complications.

After placental removal, vigorous uterine lavage (flushing) is performed to remove retained placental fragments, blood, and debris that might promote infection. Large volumes of sterile fluid are infused into the uterus and drained out repeatedly, until return fluid runs clear. This lavage is critical in preventing post-removal infection.

Intrauterine medications are typically delivered after lavage, including antimicrobial agents to prevent or treat infection developing post-removal. Systemic antibiotics are also given, often started immediately upon diagnosis before placental removal. Some veterinarians give high-dose antibiotics given the risk of severe infection.

Anti-inflammatory medications including NSAIDs are important, particularly if laminitis signs are present or suspected. Phenylbutazone or other NSAIDs help reduce inflammation triggered by retained placental toxins. These are often combined with other supportive treatments.

Intravenous fluids support the mare during treatment and recovery, particularly if hemorrhage has been significant or if the mare shows signs of systemic illness. IV fluids support kidney function, cardiovascular function, and overall recovery.

Stall rest and close monitoring follow placental removal. Continued observation for fever, discharge, or other complications is essential. Some mares recover smoothly while others develop post-treatment complications including infection despite treatment, laminitis, or other problems requiring continued intensive management.

Immediate post-removal management focuses on monitoring the mare closely for complications. Checking temperature regularly (every 2-4 hours initially) allows detection of fever indicating infection. Monitoring for discharge, checking appetite and water intake, and observing attitude and comfort help identify problems developing.

Feeding management after placental retention should be conservative initially. Many mares aren't interested in feed immediately after foaling anyway, and the additional stress of placental retention and removal sometimes reduces appetite further. Offering good quality hay and water, allowing the mare to eat small amounts as she shows interest, prevents forcing feed on an already stressed mare. Most mares gradually return to normal eating within 24 hours.

Foal nursing should continue normally unless the mare is severely compromised. Most mares maintain nursing despite placental complications, and nursing maintains important foal-dam bonding and foal nutrition. Separating mare and foal unless absolutely necessary should be avoided.

Medication administration continues as prescribed by the veterinarian. Antibiotics are given for the full prescribed course even if the mare seems improved. Anti-inflammatories continue as directed. Pain medication helps the mare feel more comfortable if she's experiencing pain.

Monitoring uterine discharge—noting color, consistency, and odor—helps identify infection developing. Normal post-foaling discharge is reddish-brown initially, becoming clear or whitish over days. Foul-smelling, greenish, or purulent discharge indicates infection requiring intervention. Increasing discharge rather than decreasing might suggest retained placental fragments.

Laminitis monitoring is critical because laminitis secondary to retained placenta can develop severely. Watching for sensitivity, lameness, heat in the feet, or reluctance to bear weight helps catch developing laminitis. Some mares benefit from laminitis support including stall rest on soft footing, appropriate pain control, and specialized care if laminitis develops.

Stall management should provide comfortable clean bedding, good air quality, and accessibility to water and feed. The mare shouldn't be turned out in rough terrain if laminitis is a concern. Many retained placenta cases warrant stall rest for at least several days to a week post-removal.

Continued veterinary observation and follow-up exams are important. Some veterinarians recommend follow-up ultrasound examination of the uterus several days after placental removal to confirm complete removal and assess for retained fragments. If complications develop, rapid intervention prevents progression to catastrophic disease.

Prevention of retained placenta centers on maintaining uterine health before foaling. Mares with chronic uterine infections should have pre-breeding treatment to reduce infection risk. Careful management preventing placental inflammation or early separation before foaling helps reduce retention risk. Mares with history of retained placenta should be monitored carefully during pregnancy and prepared for increased vigilance during foaling.

Prenatal ultrasound identification of twin pregnancies allows preparation for increased foaling complications and retained placenta risk associated with twins. If twins are confirmed prenatally, preparing for potential complications and having veterinary help immediately available dramatically improves outcomes.

Pregnant mare care including appropriate nutrition, stress management, and regular veterinary monitoring supports normal placental development and foaling. Mares in good condition with optimized nutrition show better foaling outcomes than poorly nourished mares.

Care during foaling including immediate recognition of placental delivery failure and rapid veterinary intervention is the key to successful management. Mares with experienced caretakers present during foaling who recognize the 3-hour rule and respond rapidly have better outcomes than those where retained placenta goes unrecognized for extended periods.

Outlook for mares with retained placenta varies depending on how quickly treatment was initiated, how completely the placenta was removed, and what complications develop. Mares treated within the first few hours of retention often recover completely with minimal complications. Those where treatment is delayed develop more severe complications and worse outcomes.

Severe complications can develop despite appropriate treatment including overwhelming infection (endotoxemia or septicemia), severe laminitis, uterine rupture if severe trauma occurs during removal, or hemorrhage. Some of these complications are life-threatening or might require difficult decisions about treatment continuation versus euthanasia.

Mares that recover without severe complications usually have good long-term prognosis. Most recovered mares return to normal function and can potentially be bred again. However, some develop chronic problems including uterine scarring affecting future breeding, chronic uterine infection, or recurrent retained placenta.

Future breeding in mares with history of retained placenta warrants careful consideration. Some mares can successfully breed and foal again despite previous retention. Others have recurrence or development of other problems. Discussing realistic expectations with your veterinarian about breeding previously affected mares helps guide appropriate decisions.

Mares losing foals to complications secondary to retained placenta or those dying from complications represent the worst outcomes. However, with rapid appropriate treatment, mortality rates in mares are relatively low, and most recover to continue productive lives as broodmares or other uses.