It keeps the uterus closed. It is usually very firm. At the end of pregnancy, contractions and other changes cause the cervix to soften and dilate so the baby can be delivered. Incompetent cervix is usually diagnosed after a woman has lost a pregnancy at 18-22 weeks without having labor. Other reasons for pregnancy loss must be excluded.
Incompetent cervix is often over diagnosed.
Sometimes incompetent cervix is diagnosed based on ultrasound findings. On ultrasound, the cervix is sometimes seen to be very short. The internal opening may be dilated. The cervix may shorten further when pressure is put on the uterus. Some women complain of pelvic heaviness, or lots of discharge.