Placentitis is an inflammation within the placenta, it is responsible for the majority of late term abortions in broodmares. The most common type is ascending placentitis where bacteria enters the sterile uterus from the lower reproductive tract (e.g. mares with poor vaginal conformation). Viral and fungal infections can also cause placentitis.

Early detection of this condition is vital to maintain the pregnancy and deliver a healthy foal.

Mares with ascending placentitis may present clinical signs such as, vaginal discharge, premature mammary gland development and premature lactation

HOWEVER, abortion of the foal is often the first sign that your mare has a problem. This is why it is important to know the past history of your mare and her previous pregnancies (if she has had any) as problems may indicate towards an underlying condition.


Diagnosis is not always easy to make but if placentitis is found early enough it can improve that chances of positive clinical outcomes. Ultrasound screening (ideally rectal and abdominal) has been the main tool in diagnosing placentitis.

Infection is often located in the area known as ‘the cervical star’ (or caudal placental pole). We often measure the thickness of the uterus and placenta (known as CTUP – combined thickness of the uterus and placenta) to assess for any thickening and abnormalities.

Frequent and ongoing monitoring is required in some cases.


Ideal treatment strategies for placentitis are aimed at curing the infection, reducing the inflammatory response and prolonging the pregnancy to as close to term as possible.

This is achieved by using broad spectrum antibiotics (those which cross the foetal membranes effectively), anti-inflammatory medications and hormonal support.

The earlier placentitis is discovered and treated the better for the foal as the combination allows complete growth and formation with a full term pregnancy.

If you have any more questions or concern about this condition, please call the clinic on (02) 49276135 to chat to our reproduction team!