How to recognize and manage the high-risk pregnancy mare

Introduction

The early diagnosis of a pregnancy that is in jeopardy could be a challenging issue for veterinarians. There are many conditions that could put the pregnancy of the mare at risk, particularly during the last trimester of pregnancy.

Mares could become high risk of carrying a foal to term either because they have medical/reproductive issues at the time of breeding that can be exacerbated during the pregnancy, or because they develop medical conditions during the gestation. Examples of pre-existing conditions include metabolic syndrome, osteo-arthritis, metabolic syndrome and poor perineal conformation/uterine health. Examples of conditions that may develop as gestation advances include Undiagnosed twins, placental infection, excessive abdominal distention, abdominal or Musculo-skeletal pain. Some of these although not directly related to the reproductive tract can put the mare and/or the fetus at risk.

Conditions causing the risk of the mare or the fetus

It is important particularly for mares with a history of reproductive problems to monitor the pregnancy on a regular basis. Things that should be evaluated include the placental thickness, the nature of the allantoic and of amniotic fluid and the viability of the fetus gauge through the fetal heart rate. It is not uncommon for mares with history of previous pregnancy losses to be maintained on a progestagen such as altrenogest for prolonged period of periods of time. Failure to monitor mirrors that are on prolonged therapies can result in the death of the fetus with a consequent mummification or maceration.

Poor perineal confirmation coupled with poor breeding management could result in seeding the vagina or the cervix with bacteria that could colonize the pregnant uterus and the placenta provoking a placental infection jeopardizing the viability of the fetus.

Hydropic conditions such as hydro-allantois or hydro amnion Our conditions that have a sudden onset of large abdominal distension with the mere slightly painful and on the rectal exam it is difficult to identify the foal due to the large volume of fluid and the tightness of the uterus. Depending on the length of gestation it is often recommended to induce abortion.

Colic in the late term pregnant mare could be challenging because of the size of the uterus occupying a large portion of the abdominal cavity. Clinical signs become a critical part of making a diagnosis. Colleague of gastrointestinal origin we’ll have a mayor with moderate to severe pain. Oftentimes the rectal exam could be difficult and other signs such as fecal production and gastrointestinal motility become hallmarks for the diagnosis.

Uterine torsion is another important differential in colic. However, these mares often will present with low grade pain of prolonged duration That most of the time is refractory to painkillers. Rectal exam is the most important procedure for diagnosis. Musculoskeletal problems include weakening of the ventral abdominal musculature With the development of herniation or pre pubic tendon rupture. Treatment for these conditions include pain management and support of the ventral abdominal musculature. In addition these mares should be considered candidates for following induction. Depending on the situation the reproductive future of these mares is likely to be limited to assisted reproductive technologies such as embryo transfer.

Osteoarthritic conditions, or soft tissue problems of the feet and legs could also represent a problem for late term pregnant mares. As the fetus increases in size and the mare becomes heavier, chronic pain could become an issue. Orthopedic management as well as pain management become an important part for a good prognosis.

Often owners as well as veterinarians are concerned because of excessively prolonged gestations in mares. In the southern United States it is common that mares that have been fed fescue gras contaminated with the fungus Acremonium Coenophialum will have a low prolactin level particularly in the last trimester of pregnancy making these mares delay the readiness for birth. As a consequence, these mares often will have a thickened placenta and weak foals that often ha foals are week. Other reasons why mares could have prolonged gestations include uterine fibrosis reducing utero-placental contact, time of breeding and a sire effect.

Summary

In summary, there are several conditions that can put the health of the mare and or the fetus at risk. Consequently the veterinarian must be vigilant to the sudden a d sublte changes that could indicate possible problems. Early detection becomes paramount in order to be able to support both mare and fetus in order to carry a pregnancy to term. Veterinarians attending high risk mares must always keep in mind that high risk mares may have a higher incidence or be prone to dystocia. In addition foals born from high risk mares even though they might appear healthy in the first few hours of life, need to be observed closely to insure that they normal.

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