Fetal Malposture and Dystocia
A normal delivery progresses in three stages. When growing in the mare, the foal grows like there are sleeping on their back with hind legs pointing forward towards the mares head (Figure 1). During the first stage of labor, the foal repositions its body and legs in the womb so that it looks like it is “jumping out” of the mare with the abdomen down and both front limbs and head pointing towards the mare’s tail (Figure 2). The first stage of labor lasts about 30 minutes to 6 hours. The mare becomes restless, starts to pace around the stall, and shows variable degrees of discomfort that can resemble colic. This is a sign that the contractions have begun. The second stage of labor is the actual delivery of the foal, and it begins when the placental membrane ruptures and the allantoic fluid rushes out (“breaking water”). After the mare breaks water, the fetus is usually delivered within 30 minutes. The third stage of delivery happens after the foaling, and it ends when the mare passes the placenta. The placenta should be expelled within 3 hours post-delivery.
During the first stage of foaling, the foal should reposition himself in the uterus with the belly down, both front limbs and head extended forward into the birth canal, and the hind limbs extended back. This allows the long extremities of the foal to be delivered through the birth canal without getting caught in the pelvis. If you don’t see TWO FEET and the HEAD come out first, SOMETHING IS NOT RIGHT! This could be a sign that the foal is not properly oriented within the birth canal and may lead to a dystocia.
By definition, dystocia is difficulty in giving birth, or inability to give birth unaided. If the mare continues to strain, she gets up and down and you don’t see both of the foal’s feet come out first, or the delivery is taking longer than 30 minutes after the start of stage 2, then there is a problem. The most common cause of dystocia is fetal malposture, which means that the foal’s limbs and/or head are in abnormal positions (see Figures 3 – 5 for example). Fortunately, veterinarians and experienced broodmare managers can generally correct simple cases of dystocia on the farm. However, if the dystocia is not easily corrected, the mare may need to be referred to a veterinary hospital. At a referral hospital, the mare can be placed under general anesthesia and have her hind end raised into the air using a hoist. This allows the veterinarian to reposition the foal in the uterus (where there is more room vs. the pelvis) and does not have to deal with the forceful contractions of the mares uterus. Also, a C-section can be performed if the orientation of the foal cannot be corrected for a vaginal delivery (e.g. breech position = foal’s hips present first. See figure 6).
If you suspect that your mare is having a dystocia, you need to call your veterinarian immediately. While you are waiting for your veterinarian to arrive, keep your mare calm and standing or walking to prevent her from straining excessively. Start to prepare the mare for delivery by wrapping the tail, and cleaning the perineal area with warm water and mild soap. It is also important to get the trailer ready in case you need to take the mare to a referral hospital.
The greatest chance for a positive outcome is to recognize a problem quickly and seek immediate medical attention for the mare.
Figure 1: The position of the growing foal
Figure 2: This foal is rotating into position in preparation for delivery
Figures 3: one limb extended backwards
Figure 4: One limb over the head
Figure 5: Both hind limbs flexed forward (“Dog Sitting” position)
Figure 6: Foal’s hips are in the birth canal with the hind limbs extended forward (“Breech”)
S. James Fukuda, DVM – 1/24/12