Table 2.

Classification of endometrial biopsy and potential effect on fertility (adapted from Powers et al. [26])

Categories	Characteristics	Effect on fertility	Prognosis
Grade 1A	Normal endometrium	Normal	Very good
Grade 1B	Few lymphocytes within the endometrium. Siderophages (postpartum or postabortion). Low-grade infection, inflammation due to mating	Slightly decreased	Good if treated promptly
Grades 2A and 2B	Active and acute, chronic, or chronic active endometritis. Chronic inflammation is more deeply located in the endometrium, compared with active and chronic active inflammation	Reduced conception rate, increased early embryo death	Good if recent, poor if the female has been barren for >1 year
Grade 3A	Chronic endometritis with glandular fibrosis	Increased early embryonic loss or abortion	Poor
Grade 3B	Uterine neoplasia		Poor