What you see. The starting point for addressing any equine health related issue is your observation.


Pregnancy Loss, Late-Term (6 Months to Term)


Late term abortion is relatively uncommon. It usually results from the existence of twin fetuses, bacterial infection of the placenta (placentitis), or a viral infection. When mares abort in later pregnancy, there is a greater chance of a difficult or complicated delivery (dystocia) or a retained placenta, and more danger to the mare.

The birth of a small, stillborn fetus at 8-10 months of gestation is always cause to consider that there may be a second fetus still in the mare. Retained placenta and subsequent uterine infection is a risk after twin abortion.

Aborted fetuses are often eaten by scavengers before they are found, so just because you did not find a fetus does not mean that your mare did not abort. Red vaginal discharge or an inappropriately full udder in a supposedly pregnant mare may be all that you notice or see.

  • Code Red

    Call Your Vet Immediately, Even Outside Business Hours
    • If the mare has also retained her placenta for longer than 3 hours.
    • If the results of the Whole Horse Exam (WHE) in the resting horse indicate fever (Temp >101F/38.3C) or heart rate greater than 48 BPM.
    • Questions coming up around foaling should usually be discussed right away with your vet.
  • Code Orange

    Call Your Vet at Their First Available Office Hours
    • If the results of the Whole Horse Exam (WHE) suggest the horse is otherwise normal.
You also might be observing
Very Common
Less Common
more observations

your role


What To Do

If possible, always save the placenta and aborted fetus in a cool place for your vet to evaluate when they evaluate the mare. Keep the mare isolated and fetal fluids away from your other horses until your vet has evaluated the situation. Monitor your recently aborted mare for a few days. Watch attitude, appetite and rectal temperature to be sure those things remain normal.

What Not To Do

Do not assume your mare is fine after aborting. Do not pull on a retained placenta.

your vet's role

After abortion, your mare's general health and reproductive health should be evaluated by a vet, who may suggest diagnostics to determine the cause. Your vet examines the mare to be sure there is not another fetus and that she has properly shed the placenta. By determining the cause, you and your vet may be able to limit future damage to your mare's reproductive health, ensure fertility for rebreeding, or even protect other broodmares in the group (assuming the diagnosis relates to an outside environmental cause).
Questions Your Vet Might Ask:
  • Does the mare appear normal otherwise?
  • Did you find an aborted fetus?
  • What is the mare's attitude and appetite like now?
  • What is the horse's rectal temperature?
  • What are the results of the Whole Horse Exam (WHE)?
  • Did the mare passed the placenta whole?
  • What is the appearance of the aborted fetus?
  • Do you vaccinate the mares for rhino abortion at 5, 7 and 9 months?
  • Has the mare passed her placenta whole?
  • Did the mare undergo an ultrasound in early pregnancy to ensure no twins?
  • Can I examine the placenta?
  • What was the mare's breeding dates?

Diagnoses Your Vet May Consider

The cause of the problem. These are conditions or ailments that are the cause of the observations you make.

Very Common
Less Common
more diagnoses

Author: Doug Thal DVM Dipl. ABVP