Insufficient cervix

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Alternate Names

Incompetent cervix; Weak cervix

What Is an Insufficient Cervix?

The cervix is the narrow lower end of the uterus that goes into the vagina.

  • In a normal pregnancy, the cervix stays firm, long, and closed until late in the 3rd trimester.
  • In the 3rd trimester, the cervix starts to soften, get shorter, and dilate (open up) as a woman’s body prepares for labor.

An insufficient cervix may begin to dilate too early in pregnancy. If there is an insufficient cervix, the following problems are more likely to occur:

What Causes It?

No one knows for sure what causes an insufficient cervix, but these things may increase a woman’s risk for it:   

  • Being pregnant with more than 1 baby (twins, triplets)
  • Having an insufficient cervix in an earlier pregnancy
  • Having a torn cervix in an earlier birth
  • Having miscarriages in the fourth month or later in the past
  • Having late-term abortions in the past
  • Having a cervix that did not develop normally
  • Having a cone biopsy of the cervix in the past due to abnormal Pap smears

How Do I Know I Have It?

Often, you will not have any signs or symptoms of an insufficient cervix unless you have a problem it might cause. This is how many women first find out about it.

If you have any of the risk factors for insufficient cervix:

  • Your doctor may do an ultrasound to look at your cervix when you are planning a pregnancy, or early in your pregnancy.
  • You may have physical exams and ultrasounds more often during your pregnancy.

If you have an insufficient cervix and miscarry in the second trimester of pregnancy, it may feel like pressure in your belly or a “lump” in your vagina. You will probably not feel contractions.

Later in the pregnancy, you will need to learn to know when you are in labor.

How Is It Treated?

If you have an insufficient cervix, your health care provider will likely suggest [bedrest-60-NEW]. During bed rest, you will be advised not to have sex. Do not use tampons, and especially do not douche (which is absolutely never ok during pregnancy and is not recommended at any other time either).

Your health care provider may suggest you have a cerclage. This is a surgery to treat an insufficient cervix. During a cerclage:

  • Your cervix will be stitched closed with a strong thread for the whole pregnancy.
  • You will be given medicine to prevent a miscarriage that could occur from the surgery.
  • Your stitches will be removed near the end of the pregnancy, or sooner if labor begins early.

Cerclages work well for most women. But many women who do not have the surgery still have healthy babies.

Talk with your health care provider about the risks and benefits of a cerclage to help you decide whether or not to have one.


Owen J, Mancuso M. Cervical cerclage for the prevention of preterm birth. Obstectric and Gynecology Clinics. Philadelphia, Pa: Saunders Elsevier; 2012:39(1).

Version Info

  • Last reviewed on 8/23/2012
  • Susan Storck, MD, FACOG, Chief, Eastside Department of Obstetrics and Gynecology, Group Health Cooperative of Puget Sound, Bellevue, Washington; Clinical Teaching Faculty, Department of Obstetrics and Gynecology, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.

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