An abnormal weakness of the cervix which can result in miscarriages. Usually the cervix remains closed until the onset of labour. An incompetent cervix may gradually widen from about the 12th week of pregnancy, or may suddenly open during the second trimester.
A pelvic examination or ultrasound scanning can help pick up the condition. A stitch applied around the cervix is used to treat, at around the 12th week of pregnancy. This is kept in place until the end of pregnancy and is then cut which allows the mother to deliver the baby normally.