Uterine synechiae in pregnancy: expanded criteria for recognition and clinical significance in 28 cases.

Amniotic sheets caused by preexisting uterine synechiae may be recognized in pregnancy by presence of a bulbous free edge containing a hypoechoic zone and Y-shaped splitting of the sheet at the endometrial margin. The placenta is contiguous with, is indented by, or extends along the synechia in up to two third of cases. In 28 cases, amniotic sheets did not cause fetal damage, but they did lead to a significantly higher primary cesarean section rate by causing fetal malpresentation and possibly by contributing to low placental implantations and bleeding. Previous curettage had been done in 78% of these patients.