If a dark red, velvety membrane is presenting at your mare's vulva instead of the smooth white or translucent sac, the placenta has separated early and the foal has stopped receiving oxygen. Open that membrane immediately with a knife or scissors, get the foal out, and call your veterinarian. Dr. Patrick McCue of Colorado State University's Equine Reproduction Laboratory states it directly: "The placental membrane should immediately be opened with a sharp instrument such as a knife or scissors." Merck Animal Health's foaling guidance lists a red bag as an immediate veterinary emergency and says to tear or cut the red membrane at once to prevent the foal suffocating. Published guidance is consistent that the foal cannot wait for the vet to arrive. Do the cutting first, then keep the vet on the phone.
If you are reading this mid-foaling, the sequence is immediately below. Everything else on this page can wait until afterwards.
The sequence, in order
- Confirm what you are looking at. Red and velvety at the vulva is the outer placental membrane (the chorioallantois). Smooth, whitish and translucent is the amnion, which is normal. If it is red, continue. If you are unsure, treat it as red and act; opening an amnion costs the foal nothing, waiting on a red bag costs it everything.
- Have someone hold the mare's head if anyone else is there. If you are alone, work anyway.
- Open the membrane with a sharp instrument. McCue: a knife or scissors. Published owner guidance describes grasping the protruding membrane with a clean gauze pad or cloth, pulling it away from the foal inside, and then tearing or cutting it open with blunt-ended bandage scissors. Cut away from the foal. Expect a release of allantoic fluid, which McCue notes causes a transient pause in uterine contractions.
- Get the foal delivered as fast as possible. Merck's guidance is to assist delivery by pulling gently on the forelimbs. Pull with the contraction, not against it, and in the direction of the mare's hocks, never straight out.
- If what you find is not two forelimbs with the head following, stop pulling and call. Merck lists abnormal position (only one forelimb showing, no head, or hind limbs first) as its own immediate-call-the-vet trigger. A red bag plus a malpresentation is beyond what an owner can fix, and pulling on it makes it worse.
- Call your veterinarian, and keep them on the line if you can. This is not a call you make afterwards to report. It is a call you make while working.
- Check that the foal is breathing. If it is not, published guidance for this emergency describes mouth-to-nostril resuscitation: hold the foal's head elevated at roughly 30 to 45 degrees, seal one nostril and the mouth, seal your lips around the open nostril, and blow firmly, watching for the chest to rise. Continue until the foal breathes or help arrives.
- Give oxygen if you have it and know how, per McCue. Most owners do not, and that is fine. Steps 3, 4 and 7 are the ones that matter.
- Treat the foal as a patient even if it looks fine. McCue: "Foals may develop problems associated with hypoxia even though they may appear to be normal at birth." A red bag foal needs a veterinary examination regardless of how well it seems.
How to recognize it, in the dark, in a hurry
The equine placenta has two membranes. The outer one, the chorioallantois, attaches to the uterus and its outer surface is brick red and velvety because of the microcotyledons that interlock with the uterine lining. The inner one, the amnion, surrounds the foal and is smooth, pale and translucent.
In a normal foaling the chorioallantois ruptures at the cervical star, a smooth white patch of membrane that sits against the cervix and has no microcotyledons. That rupture is your mare "breaking her water," and what you then see emerging is the white amnion with the foal inside.
In a red bag, the chorioallantois has not ruptured at the cervical star. Instead it is being pushed out ahead of the foal, still attached to nothing useful, and the red velvet you are looking at is the surface that should still be gripping the uterine wall. McCue notes you can confirm it by seeing the cervical star on that chorionic surface.
Red and velvety: emergency. White, smooth and see-through: normal. That is the entire visual test, and it is why a working flashlight is the least glamorous and most important item in the mare foaling kit checklist.
Why the minutes count
A foal in the uterus gets its oxygen through the placenta. Premature separation cuts that off. McCue describes failure of the outer membrane to rupture during labor as causing a rapid decrease in oxygen transport to the fetus.
For context on how little time there is: McCue puts normal foaling at within 15 to 30 minutes of the mare breaking her water, and Merck gives second-stage labor as 10 to 30 minutes with an instruction to call immediately if 30 to 45 minutes pass without a delivered foal. A red bag consumes that budget with the foal already oxygen-starved rather than merely on the clock.
The consequences of getting it wrong are not only death. Published descriptions of hypoxia in these foals include hyperexcitability, weakness, absent suckling reflex, blindness and disorientation, with brain damage in prolonged cases. This is why "it seemed fine, so we didn't call" is the wrong ending to a red bag story.
What causes a red bag delivery in a horse, and can you prevent it
Largely, no, and that is worth saying plainly rather than selling you a prevention routine.
McCue attributes premature placental separation primarily to placental infection (placentitis), fescue toxicity and stress, and reports that premature separation of the placenta accounts for up to 5 to 10 percent of all cases of abortion, stillbirth and perinatal death. Published owner-facing coverage of the condition notes there are usually no early warning signs before the red membrane appears.
What you can do in advance is manageable and boring: good broodmare veterinary care through gestation, including attention to anything suggesting placentitis, and management of fescue in the pasture if that applies where you are, both of which are conversations with your own vet. Then preparation: scissors in the kit, a working flashlight, your vet's after-hours number posted physically at the stall, and knowing your actual drive time from their clinic.
What happens afterwards
For the mare, the outlook is generally good. Published guidance on premature placental separation states she is in no greater danger than in a normal birth and that future pregnancies are possible without an increased risk of recurrence. That is genuinely reassuring and it is one of the few reassuring sentences on this page. Discuss her individual history with your vet before rebreeding.
For the foal, the outlook depends almost entirely on how fast the membrane was opened. Foals that were oxygen-deprived for longer may need hospitalization and intensive care, and published accounts of severe cases describe intravenous antibiotics, daily bloodwork and days of supportive treatment. Your vet decides all of that. Your job ends at getting the foal out, breathing, and seen.
Expect the follow-up questions your vet will ask, and try to note them at the time: what time the membrane appeared, what time you opened it, how long until the foal was out, and how long until it breathed. Nobody has ever regretted writing those down.
What this page is not
Horsetin is written by a hobbyist owner and breeder, not a veterinarian. This page reproduces published veterinary guidance for a specific, visually unmistakable emergency in which the published guidance is unanimous that the attendant must act before the vet arrives. It is not a general instruction to intervene in foalings. In almost every other foaling problem, including a stalled delivery or a malpresentation, the correct action is the opposite: hands off, phone in hand. Those are covered in signs a mare is about to foal and pre-foaling restlessness or colic.
The best time to read this page is months before your mare is due, alongside the decision content in should you breed your mare, and with your own vet on the phone telling you what they want you to do in their practice. Ask them that question in daylight. Print their answer. Put it in the kit.
FAQ
What is a red bag delivery in a horse?
It is premature separation of the placenta, in which the outer placental membrane (the chorioallantois) fails to rupture at the cervical star and is pushed out ahead of the foal. Its red velvety surface appears at the vulva instead of the normal white amnion, and the foal has lost its oxygen supply.
What do I do if I see a red bag?
Open the membrane immediately with a knife or scissors, per Dr. Patrick McCue of Colorado State University's Equine Reproduction Laboratory, then get the foal delivered as fast as possible and call your veterinarian. Merck Animal Health gives the same instruction to tear or cut the membrane at once.
Should I wait for the vet before cutting?
No. Published guidance is consistent that the foal cannot wait for the veterinarian to arrive. Make the call while you work, or have someone else make it.
How common is a red bag delivery?
Dr. McCue reports that premature separation of the placenta accounts for up to 5 to 10 percent of all cases of abortion, stillbirth and perinatal death. Placentitis, fescue toxicity and stress are the causes he names, and there are usually no early warning signs.
The foal came out and seems normal. Do I still need the vet?
Yes. McCue is explicit that foals may develop hypoxia-related problems even when they appear normal at birth. Every red bag foal needs a veterinary examination.
Sources: Dr. Patrick McCue, Colorado State University Equine Reproduction Laboratory, "Red bag in horses: A foaling emergency" (published via Tri-State Livestock News, 2026) for the recognition, the instruction to open the membrane, timing, causes and the 5 to 10 percent figure; Merck Animal Health USA's broodmare labor guidance for the stages, the 30 to 45 minute trigger, abnormal presentation and the red bag instruction; published owner-facing guidance on premature placental separation for the resuscitation description and prognosis. Horsetin is written by a hobbyist owner and breeder, not a veterinarian. Ask your own vet, before foaling season, exactly what they want you to do.