Key takeaways
Dystocia in mares is the inability to pass a foal through the birth canal without assistance when attempting to give birth.
- Dystocia is always a veterinary emergency
- Usually due to abnormal or improper positioning of the foal
- Other possible causes are twinning, malformation of the foal, enlarged head on the foal, small pelvic size in the mare, or obesity in the mare
- Diagnostics consist of a complete physical evaluation, vaginal examination, and rectal palpation
- Treatment is case-specific and options include Cesarean section (C-section), assisted vaginal delivery, euthanasia of the mare and removal of the foal, and fetotomy
- The prognosis varies depending on the elapsed time between onset of stage-2 labor and delivery
- The chances of a successful delivery with a healthy foal and mare decreases radically at 40 minutes after the onset of stage-2 labor
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A closer look: Dystocia in Horses
Dystocia is common in horses. It happens in about 10% of pregnancies, with a higher rate in miniature horses.
Dystocia is always an emergency.
Foals must be delivered within 40 minutes of the onset of stage-2 labor, which begins when the water breaks.
The prognosis varies according to the time necessary for the delivery. Within 40 minutes after the onset of stage-2 labor, the risk of the foal being stillborn or dying after birth is less than 10%. After 40 minutes, the risk dramatically increases to 35-40%.
Risk factors
The longer it takes to deliver the foal after the onset of stage-2 labor, the more serious the situation.
Possible causes
The main cause of dystocia is malpositioning of the foal. This can involve the head, the limbs, or the entire foal.
Other possible causes:
- Twinning
- Enlarged head on the foal
- Malformation of the foal
- Small pelvic size in the mare
- Overweight mare
Main symptoms
Signs of dystocia are specific to stage-2 labor. If stage-2 labor lasts more than 40 minutes, it is probably due to dystocia.
Another typical sign is malpositioning of the foal within the vaginal canal (the normal birth position is the “diver’s position,” with both front limbs and the head situated to come out first).
Testing and diagnosis
The diagnostic process consists of a complete physical and vaginal examination. Rectal palpation can also help detect if the foal is in an unnatural position.
Steps to Recovery
Several possible options are available when it comes to treating dystocia:
- Assisted vaginal delivery using lubrication and specialized tools
- C-section
- Fetotomy (if the foal is dead and a C-section is not an option, this is the last resort to remove the foal)
- Euthanasia of the mare and postmortem removal of the live foal
The prognosis with assisted delivery or C-section is relatively good for both the mare and the foal if treatment is implemented and successful in a timely manner. However, the prognosis decreases as the time to delivery increases. After delivery, mares should be monitored for signs of retained placenta and checked for laceration or damage to the reproductive system.
Prevention
Dystocia is a possible complication of every pregnancy. Knowing the expected birth date and planning prompt access to medical care can help prevent some of the risks associated with dystocia.
Dystocia is not contagious.
Is Dystocia in Horses common?
Dystocia happens in about 10% of pregnancies. The rate is higher in miniature horses.
Typical Treatment
- Assisted vaginal delivery
- C-section
- Fetotomy
- Euthanasia of the mare and removal of the foal
