Content Map Terms

Cervical Insufficiency

Condition Basics

What is cervical insufficiency?

Cervical insufficiency means that the cervix can't stay tightly closed during the second trimester of pregnancy. Instead, the cervix opens (dilates) with little or no pain, usually before 24 weeks. This can lead to miscarriage or birth of a premature baby.

You may also hear this condition called a weak cervix or an incompetent cervix. A weak cervix is different from preterm labour. Labour causes regular, painful contractions of the uterus.

What causes it?

It's not clear what causes cervical insufficiency. But it has been linked to:

    • Damage to the cervix. A medical procedure or childbirth can sometimes damage the cervix.
    • A problem that a woman is born with. This may be a problem with how the cervix or uterus is shaped. Or it may be from weakened tissues of the cervix, for example.
    • Inflammation, infection or hemorrhage of the uterine lining.
    • An overly swollen or stretched uterus.

What are the symptoms?

Cervical insufficiency usually allows the cervix to open without pain. But some women do have mild symptoms.

If you have this condition, you may have:

  • No pain or discomfort at all.
  • Pressure down low in your pelvis.
  • Low backache or cramping.
  • Change in vaginal discharge. It could be thinner; more than before; or a brown, tan, or pink colour. You could have light spotting.

If you have any of these symptoms, call your doctor right away. Symptoms sometimes start days or weeks before the cervix dilates.

How is it diagnosed?

You have cervical insufficiency when your cervix has opened with little or no pain during the second trimester. But it is hard to know you have it before the cervix opens, when treatment might help keep the cervix closed. If you have had it in a past pregnancy, your doctor will want to check you often.

To diagnose cervical insufficiency early, your doctor can:

  • Do a physical and pelvic examination to see if your cervix is softened or dilated.
  • Use ultrasound to check your cervix. A shortened cervix can be a sign that preterm labour may happen. Preterm labour is treated differently than cervical insufficiency is.
  • Look at your pregnancy history. If you've had this condition before, your risk for having it again is higher than average.

How is cervical insufficiency treated?

If your cervix is showing signs of change in your second trimester or if you have a previous history of cervical insufficiency that puts you at higher risk, your treatment choices may include:

Watchful waiting.

Your doctor will check your cervix often. He or she may use ultrasound, pelvic examinations, or both.

Cervical cerclage.

For some women, cervical cerclage helps hold the cervix closed with a few stitches. The stitches are later taken out before labour starts.


This hormone, given as a shot or inserted into the vagina daily, sometimes prevents preterm labour.


Adaptation Date: 1/17/2023

Adapted By: HealthLink BC

Adaptation Reviewed By: HealthLink BC