A red bag delivery is a foaling emergency in horses where the placenta separates from the uterine wall too early, causing a dark red, fluid-filled membrane to appear at the vulva instead of the normal thin, whitish sac. The term comes from the deep red color of the outer surface of this membrane. It requires immediate intervention because the foal’s oxygen supply is being cut off as the placenta detaches.
Why It’s Called a “Red Bag”
During a normal foaling, the inner membrane (a translucent whitish sac) breaks on its own, releasing fluid and allowing the foal to emerge. In a red bag delivery, the outer placental membrane, called the chorioallantois, fails to rupture. Instead, it separates from the uterine wall and pushes through the vulva intact, looking like a bulging, velvety red bag. That dark red color is the outer surface of the placenta, which is normally attached to the uterine lining and never visible during a healthy birth.
What Causes Premature Placental Separation
The three most common causes are placental infections, fescue toxicity, and stress. Fescue toxicity occurs when pregnant mares graze on tall fescue grass infected with a specific fungus, which can interfere with normal placental function and hormone levels in late pregnancy. Bacterial or fungal infections of the placenta weaken its attachment to the uterus, making early separation more likely. Physical or environmental stress during late gestation can also trigger the condition.
Premature placental separation accounts for 5 to 10 percent of all cases of abortion, stillbirth, and death around the time of birth in horses. While not the most common foaling complication overall, it is one of the most time-sensitive.
Why It’s So Dangerous for the Foal
The placenta is the foal’s only source of oxygen before birth. Blood flows from the mare’s uterus across the placental attachment and delivers oxygen to the foal through the umbilical cord. When the placenta separates prematurely, that oxygen transfer drops rapidly. Unlike a normal delivery where the foal begins breathing air within moments of emerging, a red bag situation means the foal can be suffocating while still inside the intact membrane. Every minute matters: prolonged oxygen deprivation causes brain damage, organ failure, or death.
What to Do During a Red Bag Delivery
If you see a red, velvety membrane bulging from the mare instead of a normal clear or whitish sac, the membrane needs to be opened immediately. Using clean hands or scissors, cut or tear through the red membrane as quickly as possible to allow the foal to emerge and begin breathing. This is not a situation where you can wait for a veterinarian to arrive, though you should call one right away.
Once the membrane is opened and the foal is delivered, clear any remaining membrane from the foal’s nostrils and mouth so it can breathe. The foal may need stimulation, like vigorous rubbing with a towel, to encourage its first breaths. Foals delivered through a red bag event sometimes appear weak, slow to stand, or unresponsive compared to normally delivered foals, depending on how long oxygen was restricted.
A veterinarian should examine both the mare and foal as soon as possible. The mare may need treatment if the placenta doesn’t pass completely, and the foal will need monitoring for signs of oxygen deprivation, including difficulty nursing, poor coordination, or abnormal behavior in the first hours and days of life.
How to Prepare if Your Mare Is at Risk
Mares that have had a red bag delivery before are at higher risk of having another one. If your mare grazed on fescue pasture during pregnancy, the risk increases significantly, and most veterinarians recommend removing mares from fescue at least 60 to 90 days before their due date. Mares with a history of placental infection should be monitored closely in late pregnancy.
Having a foaling kit ready with clean towels, scissors, and a phone nearby makes a critical difference. Because red bag deliveries can happen quickly and often at night (when most mares foal), some breeders use foaling cameras or alarm systems that alert them when the mare begins labor. Knowing what a normal delivery looks like helps you recognize the red membrane immediately, and that recognition is the single biggest factor in whether the foal survives.
Other Uses of the Term “Red Bag”
Outside of equine medicine, you may encounter “red bag” in two other healthcare contexts. In hospitals, red bags are the standard biohazard containers used for regulated medical waste, including blood-contaminated items, lab specimens, and certain sharp objects. The CDC requires these bags to be leak-resistant, clearly labeled, and securely closed before disposal.
In the UK, the NHS uses a “Red Bag” scheme for care home residents who need hospital treatment. The red bag travels with the patient and contains their essential medical paperwork, medications, and personal belongings, helping hospital staff quickly access the information they need and speeding up both admission and discharge. The initiative originated in the London Borough of Sutton and has since expanded across England as part of the Enhanced Health in Care Homes framework.