Cervical Incompetence During Pregnancy

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Cervical incompetence, also known as cervical insufficiency, is basically a cervix that is too weak or damaged to stay closed during pregnancy. Therefore resulting in premature birth and possibly the loss of the baby, because of the shortened gestational length. This insufficiency generally shows up in the early part of the second trimester, but possibly as late as the early third trimester.


It is generally categorized as the premature opening of the cervix without labor or contractions. Diagnosis can be made either manually or with ultrasonography. The use of ultrasonography has been very helpful with the diagnosis and is made when the cervical os (opening) is greater than 2.5 cm, or the length has shortened to less than 20 mm. Sometimes funneling is also seen; this is where the internal portion of the cervix, internal os (a portion of the cervix closer to the baby) has begun to efface. The external os will be unaffected if diagnosed in time. Factors that increase the likelihood of suffering from incompetent cervix are:

  • DES exposure
  • Cervical trauma
  • Hormonal influences
  • Congenitally short cervix
  • Forced D & C
  • Uterine anomalies

If you are diagnosed after a second-trimester loss or prior to pregnancy it is suspected that you will have problems with the strength of your cervix, a cerclage (stitching the cervix closed) can be performed prophylactically at approximately 14-16 weeks. It is said that the earlier you have the cerclage performed the more likely the pregnancy is to continue.


For diagnosis made during pregnancy, you must meet certain criteria before a cerclage can be performed. You are not eligible for the cerclage if you have:

  • Hyperirritability of the cervix
  • Your baby has already died
  • You are more than 4 cm dilated
  • Your water is broken

There are five different techniques for performing the cerclage. The two most common are the McDonald and Shirodkar.

The McDonald procedure is done with a 5 mm band of permanent suture placed high on the cervix. This is indicated when there is significant effacement of the lower portion of the cervix. It is generally removed at 37 weeks, unless there is a reason to remove it earlier, like infection, preterm labor, premature rupture of the membranes, etc. It is also shown that this has very little impact on the chance for vaginal delivery.

The Shirodkar is also a frequently used technique. However, this was previously a permanent purse string suture that would remain intact for life, now they are removed around 37 weeks as well. When this type of cerclage is done, a cesarean section will always be performed. There are physicians performing modified techniques, where the delivery does not necessarily have to be by cesarean, nor the suture left intact. Ask your practitioner which procedure they perform.

The Hefner cerclage, also know as the Wurm procedure, is used for later diagnosis of the incompetent cervix. It is usually done with a U or mattress suture and is of benefit when there are minimal amounts of cervix left.

Uterosacral cardinal ligament cerclage is generally done after the McDonald and Shirodkar procedures have failed, or where there is a congenital shortened cervix or subacute cervicitis. It can be done vaginally but is frequently done abdominally. Again, cesarean delivery is mandated for birth.

The last procedure, the Lash, is performed in the non-pregnant state. It is typically done after cervical trauma that has caused an anatomical defect. There is the possible, though rare, side effect of infertility.


While these procedures are life-saving, they also have potential risks:

  • Premature rupture of membranes
  • Chorioamnionitis (Infection of the amniotic sac) (This risk increases as the pregnancy progresses and is at 30% for a cervix that is dilated more than 3 cms.)
  • Preterm Labor
  • Cervical laceration or amputation (This can be at the procedure or at the delivery, from scar tissue that forms on the cervix.)
  • Bladder Injury (rare)
  • Maternal hemorrhage
  • Cervical dystocia
  • Uterine rupture

The prophylactic procedure is generally to observe the patient for 24 hours before performing the cerclage. During this time she will be observed for preterm labor and screened for infection. Generally, this is done with the patient in the Trendelenburg position, feet above your head. Spinal anesthesia is used to prevent pain and maternal straining during the cerclage. Your bladder will be filled to try and move your membranes away from the os. You will be given antibiotics to help stave off infection, and Indocin to help your body ignore the prostaglandins released during the procedure.

After the Procedure

Post-operatively you will be on bed rest for the next 24 hours, possibly in the Trendelenburg position. And monitored for uterine activity.

Once released from the hospital you will be on pelvic rest (no sex) for the remainder of the pregnancy. You will need to have periods of rest each day and decreased physical activity. You will be seen in the office at least once weekly until birth. You will also be monitored for preterm labor. If you have any contractions you should contact your doctor right away.

Cerclage seems to be a very effective treatment for incompetent cervix. The success rates can be very high (80-90%), particularly when done earlier in pregnancy. If you have concerns about your prenatal history or suspect an incompetent cervix ask your practitioner to examine you.

3 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. American College of Obstetricians and Gynecologists (ACOG) Committee on Practice Bulletins — Obstetrics. ACOG Practice Bulletin No. 142: Cerclage for the Management of Cervical Insufficiency. Obstetrics & Gynecology. 2014;123(2):372-379. doi:10.1097/01.AOG.0000443276.68274.cc

  2. Berghella V, Szychowski JM, Owen J, et al. Suture type and ultrasound-indicated cerclage efficacy. J Matern Fetal Neonatal Med. 2012;25(11):2287-2290. doi:10.3109/14767058.2012.688081

  3. Cleveland Clinic. Cervical Cerclage: Risks / Benefits.

Additional Reading

By Robin Elise Weiss, PhD, MPH
Robin Elise Weiss, PhD, MPH is a professor, author, childbirth and postpartum educator, certified doula, and lactation counselor.