Women's Healthcare Topics

Cervical Insufficiency or Incompetent Cervix

Reviewed by James Brann, M.D.

Incompetent Cervix

The chance of miscarriage decreases greatly after you’ve have reached 14 weeks pregnant. (A majority of all miscarriages occur within the first 13 weeks of pregnancy.) Unfortunately, some women can experience a second trimester miscarriage as a result of an incompetent or weakened cervix. Approximately 25 percent of miscarriages and pregnancy losses are a result of this devastating complication.

The cervix is the narrow lower end of the uterus – it's the opening to the womb, located between the top of the vagina and the bottom of the uterus. To keep your unborn baby safe and protected, the cervix remains firm, long, and closed during a normal pregnancy. (The mucus plug seals the cervical opening to prevent bacteria from entering the womb.)

In a healthy normal pregnancy, your cervix will remain firm and shut until the final weeks of your pregnancy. Then, when your body is preparing for labor and delivery, the cervix will begin to efface (soften) and dilate (open).

What Causes an Incompetent Cervix?

Learn about the new testing for preterm labor called Fetal Fibronectin (fFN) Test

If you have an incompetent cervix, it may be due to your cervix being shorter than it should be, or due to a weakened cervix that's not as firm as it needs to be for a healthy normal pregnancy. As the weight of your expanding uterus places increasing pressure on your weak or shortened cervix, the cervix might start to grow shorter (efface) and open up (dilate) without any sign of contractions.

You may be at higher risk for an incompetent cervix if you've suffered cervical damage as a result of a previous childbirth, past abortion, D&C, or other surgical procedures on the cervix. In addition, if you were exposed to the drug DES while you were in your mother's womb, you may also be at risk for this pregnancy complication.

With cervical insufficiency, you won't feel any discomfort or pain when your cervix opens. Very few people realize that they have this complication until they experience a miscarriage or premature delivery.

Cervical insufficiency puts you at risk for a miscarriage in the second trimester, preterm labor and delivery, and a condition called premature rupture of the membranes (in which your bag of water breaks before 37 weeks pregnant, and before the onset of labor contractions).

Screening and Diagnosis for Cervical Insufficiency: Fetal Fibronectin (fFN) Test

Learn about the treatment options with an incompetent cervix.

Because of the risks that go along with preterm birth, you want to avoid this complication if possible. In the second trimester, if you are experiencing any symptoms of preterm labor (or if you're at risk for delivering early), your medical team may recommend a fetal fibronectin (fFN) test.

During a fetal fibronectin test, your vaginal and cervical fluids will be checked for the presence of the fetal fibronectin protein – the "glue-like" protein that helps bind the uterine lining and amniotic sac together. In a normal pregnancy, fetal fibronectin doesn't break down and leak out of your uterus until around 35 weeks pregnant, as labor and delivery approaches.

In the second trimester, this protein should not be present in any vaginal fluids. If you receive a negative result, you have a 99 percent chance that you will not go into labor in the next two weeks. However, if the fFN test detects traces of this protein and you get a positive result, it means that your body is getting ready for delivery.

If you get a positive result from the fFN test at this stage in pregnancy, your healthcare provider will create a plan of action to help your baby remain in the womb for longer (if this is possible).

Your doctor can also use a transvaginal ultrasound to evaluate the length of your cervix and other cervical characteristics to detect cervical incompetence.

If you are diagnosed with a short or weakened cervix, your healthcare provider may recommend weekly ultrasounds to monitor the cervix for any changes that may signal a miscarriage or preterm birth.

A Treatment Option: Cervical Cerclage

Doctors may recommend pelvic rest (no sexual intercourse) and bed rest to help ward off premature labor from an incompetent cervix. In addition they may also suggest that you undergo a surgical procedure called a cerclage placement – which involves your physician suturing your cervix shut. The suture, or surgical "stitch," will prevent your cervix from opening. When it's time for your baby to be born, the suture will be taken out and you can delivery normally.

The procedure is performed as a preventative measure between 12 to 14 weeks pregnant. It is sometimes performed in emergency situations if your cervix is thinned and starting to dilate.

In some circumstances, a cervical cerclage will not be effective. The cervical cerclage will not be performed if your cervix has dilated to 4 centimeters, if your water has broken, or If you are having contractions.

Because a cervical cerclage is a surgical procedure, it presents some risks and side effects. These include a small risk of miscarriage and pregnancy loss, significant blood loss, cervical damage, and infection. Risks are rare, and many doctors consider this procedure necessary and lifesaving.

Unfortunately, once your diagnosed with cervical insufficiency, you will experience the same problems in future pregnancies. That's why it's important for women with this condition to discuss any painful contractions, leakage, menstrual cramping, or pelvic pressure with your doctor as soon as possible.

When you have an incompetent cervix, you are often placed at bed rest near the end of your pregnancy. You may also be asked to avoid strenuous activity. In some situations, medications and drugs may be needed to stop contractions.


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