The placenta in leprosy.

Eighty-one placentae from women with leprosy and 17 placentae from healthy controls were subjected to a detailed macroscopic, light microscopic, ultrastructural, immunopathological, microbiological and biochemical study. The placental morphology and immunohistology were normal, and there was no morphological evidence of infection of the placenta due to M. leprae. No acid-fast bacilli or acid-fast bacillary granules were seen on light microscopy of any of the placentae from leprous women, although homogenates from two out of seven placentae from women with very active lepromatous leprosy contained acid-fast bacilli in very small numbers. The small placental size of women with leprosy, most marked in those with lepromatous leprosy, appears to be due to a decrease in placental cell size, rather than to a reduced number of cells in the placenta. It is postulated that the small placenta and reduced fetal birth weight observed in lepromatous leprosy are a consequence of depressed maternal immune reactivity.