An incompetent cervix, also called a cervical insufficiency, is a condition that occurs when weak cervical tissue causes or contributes to premature birth or the loss of an otherwise healthy pregnancy.

Before pregnancy, your cervix — the lower part of the uterus that connects to the vagina — is normally closed and rigid. As pregnancy progresses and you prepare to give birth, the cervix gradually softens, decreases in length (effaces) and opens (dilates). If you have an incompetent cervix, your cervix might begin to open too soon — causing you to give birth too early.

An incompetent cervix can be difficult to diagnose and, as a result, treat. If your cervix begins to open early, your health care provider might recommend preventive medication during pregnancy, frequent ultrasounds or a procedure that closes the cervix with strong sutures (cervical cerclage).


If you have an incompetent cervix, you might not experience any signs or symptoms as your cervix begins to open during early pregnancy. Mild discomfort or spotting over the course of several days or weeks is possible, however, starting between 14 and 20 weeks of pregnancy. Be on the lookout for:

  • A sensation of pelvic pressure
  • A backache
  • Mild abdominal cramps
  • A change in vaginal discharge
  • Light vaginal bleeding

Risk factors

Various factors can increase your risk of an incompetent cervix. For example:

  • Congenital conditions. Uterine abnormalities and genetic disorders affecting a fibrous type of protein that makes up your body's connective tissues (collagen) might cause an incompetent cervix. Exposure to diethylstilbestrol (DES), a synthetic form of the hormone estrogen, before birth also has been linked to cervical insufficiency.
  • Cervical trauma. If you experienced a cervical tear during a previous labor and delivery, you could have an incompetent cervix. Other surgical procedures involving the cervix, such as those to deal with an abnormal Pap test, may cause damage that contributes to cervical insufficiency.
  • Dilation and curettage (D&C). This procedure is used to diagnose or treat various uterine conditions — such as heavy bleeding — or to clear the uterine lining after a miscarriage or abortion. On rare occasions it may cause structural damage to the cervix.


An incompetent cervix poses risks for your pregnancy — particularly during the second trimester — including:

  • Premature birth
  • Pregnancy loss


You can't prevent an incompetent cervix — but there's much you can do to promote a healthy, full-term pregnancy. For example:

  • Seek regular prenatal care. Prenatal visits can help your health care provider monitor your health and your baby's health. Mention any signs or symptoms that concern you, even if they seem silly or unimportant. Regular dental checkups during pregnancy are important too.
  • Eat a healthy diet. During pregnancy, you'll need more folic acid, calcium, iron and other essential nutrients. A daily prenatal vitamin — ideally starting a few months before conception — can help fill any dietary gaps.
  • Gain weight wisely. Gaining the right amount of weight can support your baby's health. A weight gain of 25 to 35 pounds (about 11 to 16 kilograms) is often recommended for women who have a healthy weight before pregnancy.
  • Avoid risky substances. If you smoke, quit. Alcohol and illegal drugs are off-limits, too. In addition, medications of any type — even those available over-the-counter — deserve caution. Get your health care provider's OK before taking any medications or supplements.

If you have an incompetent cervix during one pregnacy, you're at risk of premature birth or pregnancy loss in later pregnancies. If you're considering getting pregnant again, talk with your health care provider to understand the risks and what you can do to promote a healthy pregnancy.

March 12, 2015
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