Download Placentitis - Agnes Banks Equine Clinic

Placentitis
The silent enemy of your unborn foal
By Bree Vandyke BVetBio/BVSc (hons)
Having your mare lose her pregnancy is devastating both emotionally and financially. Abortion can
be caused by a variety of factors and events.
Placentitis (inflammation of the placenta) has been recognised clinically for a number of years and is
considered the single most significant cause of late term abortion in horses.
What causes placentitis and is my mare at risk?
Placentitis may be caused by bacteria, fungi or viral agents; however it is most commonly associated
with bacterial infection. This usually arises from faecal contamination with bacteria subsequently
ascending through the vagina and cervix thus reaching the placenta. It is important to note that
placentitis is not contagious, that is, it does not occur between mares.
Although all mares are at risk of placentitis, it is more occurs in middle-aged to elderly mares that
have birthed multiple foals. Mares with poor conformation of the vulva are at increased risk of faecal
contamination and thus placentitis also. These mares are often have difficulty falling pregnant and
may have been treated for bacterial contamination of the uterus prior to conception.
What are the signs of placentitis & how does it affect pregnancy?
One of the reasons placentitis is difficult to identify and manage is that mares often do not show
outward clinical signs until the disease is well advanced. Mares sometimes show signs of placentitis
via vaginal discharge or premature udder development, however by the time these external signs
are evident it is often not possible to save the pregnancy even with intensive treatment.
Pregnancy loss associated with placentitis occurs for a number of reasons. These include inability of
the placenta to supply oxygen and nutrients to the foetus, bacterial infection of the foetus itself
leading to illness at birth or death and increased contraction of the uterus resulting in abortion.
How is placentitis monitored for?
In order to identify placentitis at an early stage, routine monitoring via ultrasound should be
implemented by your veterinarian. Ultrasonographic evaluation of the placenta is undertaken from
180 days (6 months) gestation and is repeated at monthly intervals until full term.
Using the ultrasound, the placenta is first examined for signs of separation from the uterus and fluid
accumulation between the uterus and placenta. Multiple measurements are then taken to assess
the thickness of the placenta. If there is evidence of placental separation or the placenta is thicker
than specified guidelines for the stage of gestation then placentitis may be diagnosed.
Ultrasonographic evaluation of the placenta in late gestation helps to achieve an early diagnosis of
placentitis and allow for intervention prior to development of external clinical signs, including
abortion.
Figure: Ultrasound examination of the placenta, where the line indicates the point of measurement
when monitoring for placentitis.
What can be done if my mare is diagnosed with placentitis?
Mares identified with placentitis at an early stage through ultrasound assessment, may be treated
effectively. When intervention occurs early, these mares have a good prognosis for carrying a live,
healthy foal to term even if they have a previous history of abortion. Research has shown with
effective early intervention, mares with placentitis have a greater than ninety percent chance of
carrying a pregnancy to term.
Because placentitis affects the pregnancy in a variety of ways, treatment consists of a multifaceted
approach. Your veterinarian will tailor a treatment program specific to the needs of your mare but
treatment may include antibiotics, anti-inflammatories, hormone therapy and medication to reduce
premature uterine contractions.
Once a mare is identified with placentitis, ultrasound evaluation of the placenta may need to be
undertaken more frequently than the routine monthly intervals in order to assess if treatment is
controlling infection and effectively reducing inflammation.
Agnes Banks Equine Clinic is committed to providing your mare with the best possible chance of
delivering a live foal. We are available for all your mare fertility needs, offering full fertility
assessments including placentitis scanning and assessment of foetal health throughout pregnancy.
For more information regarding placentitis scanning, feel free to contact the clinic on 02 4588 5200.