Local dynamic changes of the cervix associated with incompetent cervix before and after Shirodkar's operation.

A 31-year-old woman, gravida 2 para 1, visited our clinic for routine follow-up at 20 weeks' gestation. Although she had no abdominal pain or pressure, digital vaginal examination revealed dilatation of the internal cervical os of 1.5 cm, and transvaginal sonography demonstrated dynamic changes in the shape of the cervical canal. The patient underwent Shirodkar's operation. Routine postoperative assessment of the cervix with transvaginal sonography showed dynamic dilatation of the upper cervix (above the cerclage), which was accompanied by a sensation of pelvic pressure but no apparent uterine contractions. A healthy male infant weighing 2,980 g was delivered at 38 weeks' gestation.