Stretch-induced delivery is independent of the functional fetal role and dysfunction of the amnion and decidua: a morphologic and enzyme cytochemical study.

The role of the fetus, amnion, and decidua in stretch-induced delivery was studied in six normal pregnant women (group 1) and six in whom the fetuses had been dead in the uteri for more than a week (group 2). The cervices were distended by laminaria for 48 hours; this was followed by balloon inflation with traction. During the balloon application, regular uterine contractions were initiated and increased in all patients, with four patients in group 1 and five in group 2 aborting or being delivered within 24 hours. Light and electron microscopic studies of the amnion obtained during apparent uterine activity or after delivery revealed normal cell morphologic features in both groups although an increased fat deposition in cytoplasm was noted in group 2. Decidua parietalis exhibited normal cell morphologic features in both groups, and cytochemical demonstration of acid-phosphatase activity in decidual cells confirmed no leakage of the lysosomal enzyme into the cell cytoplasm. These findings indicate that stretch-induced delivery is initiated independent of the functional fetal role and without dysfunction of the amnion and decidua.