Characteristics of congenital cervical atresia in preoperative ultrasonography. (A, B) Type I congenital cervical atresia, showing the unique shape of a Type 1 uterus and uterine isthmus. (C) Type II congenital cervical, atresia showing a hematocele in the uterine cavity and a thickened lower uterine cavity (blind end) and wall. (D) Type III congenital cervical atresia, showing a sinus-like cervix becoming narrower from the top to the bottom; the end of the cervix was significantly enlarged. (E) Type III congenital cervical atresia, showing a long and solid cervix, with no enlarged end. (F) Type IV congenital cervical atresia, showing thickening of the wall of the cervical canal and a blind end. The liquid anechoic area of the uterine cavity was bigger than that of the cervix.