Cervical insufficiency

Cervical insufficiency (also called CI) means that a woman's cervix opens too early, before the baby is full term. This condition is also called incompetent cervix. The cervix is the opening to the uterus that sits at the top of the vagina. When the cervix is healthy, it thins out and opens at the end of pregnancy when labor begins. The baby then moves through the cervix and birth canal (vagina) to be born.

With CI, the cervix opens without labor starting. Usually the woman has no symptoms. Few women know they have cervical insufficiency until they have amiscarriage or premature birth. The woman may give birth to the baby without feeling contractions.

If you've had a pregnancy affected by CI, the condition is likely to happen again in later pregnancies.

What causes CI?

Medical experts do not always know why incompetent cervix occurs. Theories include damage to the cervix during surgery, injury during a previous birth, and exposure to certain drugs.

Cervical length appears to be a factor. The shorter the cervix, the more likely you are to have cervical insufficiency. Ask your health care provider about having an ultrasound to check for short cervix.

How is CI diagnosed?

Providers have not found a reliable way to routinely check all women for cervical insufficiency. If a woman has previously lost a pregnancy in the second or third trimester, vaginal ultrasound during the next pregnancy may help predict she's at risk for preterm birth.

How is CI treated?

Providers sometimes recommend:

• Bed rest and reduced physical activity. While these methods are common, research has not proven them to be effective.
• Pelvic rest. This means no sex, tampons or douching.
• Cerclage. The doctor puts a stitch in the cervix to keep it from opening too early. The stitch is removed at about 37 weeks of pregnancy.