The Use of Endometrial Biopsies in Formulating a Treatment Plan

Introduction
Histologic descriptions of the mare’s endometrium were reported at least as early as the 1920’s. However, it was not until the publications and classifications proposed by Robert Kenney and Sidney Ricketts in the mid- to late 1970’s that use of endometrial biopsy for diagnostic and prognostic purposes in the mare was widely appreciated. Following this and the development of suitable instruments, endometrial biopsy sample submission by practitioners for histological evaluation has been primarily used to help diagnose the contribution of the endometrium to infertility or embryonic/fetal loss, as an integral part of the breeding soundness examination, and as a screening tool in pre-purchase examinations as well as for assessing the suitability of mares as embryo donors and recipients. The histological evaluation of the endometrium is also a way to monitor patient response to therapy when uterine infections or other endometrial abnormalities are diagnosed and treated. An improvement in the biopsy score following treatment (i.e., disappearance or decrease in the severity of pathological changes detected in a previous endometrial biopsy) has been shown to be more closely related to the subsequent fertility of mares than simply basing a prognosis for fertility on the histological assessment of a single pre-treatment biopsy sample. One of the most valuable, yet underutilized benefits of endometrial biopsy evaluation is in formulating a treatment plan prior to initiating therapy. [...]