Cervical Insufficiency

Cervical insufficiency (CI) is when the cervix is not strong enough to keep a baby (fetus) inside the womb (uterus). It occurs in the 2nd and early 3rd trimesters of pregnancy. The cervix will enlarge (dilate) on its own without contractions. When this happens, the membranes around the fetus will often balloon down into the birth canal (vagina). The membranes may break, which could end the pregnancy (miscarriage).


The cause of a cervical insufficiency is often not known. Possible causes include:

  • Injury to the cervix from a past pregnancy.

  • Injury to the cervix from past surgeries.

  • Being born with this defect of the cervix.

  • Cold cone, laser or LEEP (Loop electrocautery excision procedure) to the cervix.

  • Over dilating the cervix during an abortion.

  • Being exposed to DES (diethylstilbestrol) during pregnancy.

  • Lack of tissue (elastin and collagen) in the cervix that holds the baby in uterus.

  • Shorter cervix than normal.


  • Spotting or bleeding from the vagina.

  • Feeling pressure in the vagina.

  • Unusual or abnormal vaginal discharge.


  • In many cases, the diagnosis is not made until after the pregnancy is lost.

  • Often this diagnosis will be made by exam.

  • Sometimes, an ultrasound of the cervix may be helpful. The ultrasound measures and follows the length of the cervix in women who are at risk of having CI.

  • Your caregiver may follow the dilatation of the cervix. Often, the diagnosis cannot be made until it happens. When this is the case, there is a much greater chance of early loss of the pregnancy. This means the baby is born too early to survive outside of the mother.


  • A high risk patient needs to get frequent vaginal exams and serial ultrasounds.

  • Tie a suture, like a purse string, around the cervix (cerclage), before getting pregnant.


When CI is diagnosed early, the treatment is a cerclage. This gives the cervix added support. The cerclage helps carry the baby to term. This is usually done before the first trimester (12 to 14 weeks). Cerclage is usually not done after the second trimester (24 weeks) unless it is an emergency. Your caregiver can discuss the risks of this procedure. The cerclage suture may be removed when labor begins or at term before labor begins. The suture can also be left in place for future pregnancies. If left in place, the baby is delivered by Cesarean section.


  • Keep your follow-up prenatal appointments.

  • Take medication as directed by your caregiver.

  • Avoid physical activities, exercise and sexual intercourse until you have permission from your caregiver.

  • Do not douche or use tampons.

  • Resume your usual diet.


You develop abnormal vaginal discharge.


  • You have a fever.

  • You develop uterine contractions.

  • You do not feel the baby moving or the baby is not moving as much as usual.

  • You pass out.

  • You have vaginal bleeding.

  • You are leaking fluid or have a gush of fluid from your vagina.

  • You have blood in your urine or pain when urinating.