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


Pregnancy Loss, Mid-Term (6 Weeks to 6 Months)


Pregnancy loss is uncommon between 6 weeks to 6 months after conception. There are many cases in which pregnancy loss during this time frame will go undetected. Pregnancy loss during this time frame is usually due to twin pregnancies, viral abortion, or infections of the placenta.

Abortion is usually preceded by enlargement of the udder and some vaginal discharge. If a mare aborts, consider that she could have a contagious condition. Isolate her from others, and keep other horses away from aborted fetus, placenta and fluids.

  • Code Red

    Call Your Vet Immediately, Even Outside Business Hours
    • If the mare has also retained her placenta for longer than 3 hours.
    • If you have any doubt about the length of time your mare is taking to deliver.
    • A prompt vet examination of mare, fetus and placenta provides the best chance for a diagnosis.
  • 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.

your role


What To Do

For a mare that has aborted, assess the mare's general health using the Whole Horse Exam (WHE). Pay particular attention to rectal temperature, and general attitude and appetite. Check the vulvar area for swelling or wounds. Assess the placenta as well as possible for completeness.

Monitor the mare's behavior carefully for 24-48 hours. In some cases, a mare may deliver one twin fetus but still have a retained twin in the uterus.

What Not To Do

Do not assume your mare is fine after aborting. Do not pull on a retained placenta without veterinary guidance.

your vet's role

Your mare's general health and reproductive health should be evaluated by a vet. Your vet may suggest diagnostics to determine the cause of the abortion.

By identifying 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 environmental cause).

Aborted fetuses (and the placenta) 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 in a supposedly pregnant mare may be all that you notice or see.

If possible, save the placenta and aborted fetus in a cool place for your vet to evaluate. Keep the mare isolated and fetal fluids away from your other horses until your vet has evaluated the situation.
Questions Your Vet Might Ask:
  • Does the mare appear normal otherwise?
  • 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 was the mare's breeding dates?
  • Did you find an aborted fetus?
  • What is the appearance of the aborted fetus?
  • Did the mare undergo an ultrasound in early pregnancy to ensure no twins?
  • Do you vaccinate the mares for rhino abortion at 5, 7 and 9 months?
  • Can I examine the placenta?

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