Ectopic pregnancy in a European hedgehog (Erinaceus europaeus) - the first documented case

Ectopic pregnancy (EP) is defined as the implantation of a fertilized ovum outside the endometrial lining of the uterine cavity. It occurs rarely in animals and has been most frequently documented in companion and farm animals. The classifications of pregnancies were adapted from human Medicine, as only basic classifications exist in veterinary Medicine. The criteria for classifying EP in both humans and animals have been unified. The classification is based on the site of occurrence, distinguishing between tubal and abdominal pregnancies, each of which can be primary or secondary. In animals, with the exception of primates, abdominal pregnancy is the most common form.

The following report describes an EP in wild European hedgehog. Two ectopic foetuses were identified in the inguinal canal (foetus A) and abdominal cavity (foetus B) during necropsy. Both foetuses were classified as originating from a secondary pregnancy, likely having initially developed in the uterus before entering the abdominal cavity due to uterine damage. The continuity of the right uterine horn was broken most likely as a result of mechanical trauma of unknown ethiology, with the formation of a connective tissue scar. The first foetus (A) migrated through an enlarged inguinal canal to the pelvic limb, where it was discovered. The second foetus (B) was connected via an umbilical cord to the external wall of the uterus. Subsequently, a scar measuring 6 × 6 mm formed at the site of injury through which the foetus B had previously exited. Additionally the lungs were congested, and hyperplastic and metaplastic changes as well as cysts, were described in the vagina, as potential cancerous changes.

This paper describes the first recorded case of ectopic pregnancy in a European hedgehog (Erinaceus europaeus). Conclusions had occurred, were based on necropsy and histopathological examination.