Abstract
The histological changes in the placenta after intra-amniotic injection of hypertonic saline for induction of abortion were compared with those after extra-amniotic injection. In both groups a thin zone of necrotic villi was found immediately beneath the membranes. The necrotic zone was sharply demarcated from the underlying villi, which were microscopically intact. The decidual cells underneath Nitabuch's membrane showed extensive degenerative alterations. It is suggested that decidual changes rather than damage to trophoblast play a role in the induction of abortion. The mechanism by which these changes may lead to abortion is discussed.