Amniotic sheets.

Seventeen cases of an aberrant sheet of tissue in the amniotic cavity are described to expand and clarify previous observations of this entity. The sheet of tissue demonstrates a thickened base and a free edge that undulates. The fetus moves freely about the sheet of tissue. There are no associated fetal deformities, and infants have no manifestations of the amniotic-band syndrome. Evidence suggests that these sheets may originate from "wrapping" of the amniochorionic membrane over a uterine synechia. These benign sheets of tissue should not be confused with the amniotic-band syndrome.