The unsoftened portion of the uterus: a pitfall in gray-scale ultrasound studies during mid-trimester pregnancy

A review of 322 second-trimester gestations evaluated with gray-scale ultrasound frequently revealed a locally thickened or "unsoftened" portion of the uterus. The texture and gray-tone patterns of this region as well as the other gestational components are reviewed; pitfalls in identification are outlined, and factors responsible for difficulty in amniocentesis are reported.