Relaxin as a biochemical marker of placental insufficiency in the horse: A review

Abstract

Placental insufficiency (placentitis, premature placental separation) is regarded as the primary factor contributing to late term abortion and perinatal death in foals. Late term fetal and perinatal death represents a major emotional and financial loss and time investment for horse breeders. All too often when problems associated with late-term pregnancy in the horse are manifested the condition is well advanced and therapeutic intervention may not be effective in salvaging the pregnancy. However, if a compromised pregnancy due to placental insufficiency could be identified early, the pregnancy might be sustained through medical intervention. We present evidence that the placental hormone, relaxin, has the potential to serve not only as a hormonal indicator of placental function and fetal well-being in the mare, but also as a means of monitoring treatment efficacy. A non-invasive diagnostic marker could assist the veterinarian and horse breeder in identifying mares at risk for problematic pregnancies in a timely manner.