Cervical insufficiency and short cervix


  • Cervical insufficiency and short cervix can cause problems during pregnancy, including premature birth and miscarriage.

  • Treatment can help you have a healthy pregnancy and stay pregnant longer.

  • Your provider may want to check your cervix early in pregnancy if you’ve had a premature baby in the past or repeat miscarriages.

The cervix is the opening in the lower part of the uterus (womb) that opens to the top of the vagina (birth canal). During pregnancy, the cervix stays firm and closed until late in the third trimester.  It opens, shortens and gets thinner and softer so your baby can pass through the birth canal during labor and birth. In some women, the cervix opens too early during pregnancy or is shorter than normal. These conditions can cause problems during pregnancy.

What is cervical insufficiency?

Cervical insufficiency (also called incompetent cervix) means your cervix opens (dilates) too early during pregnancy, usually without pain or contractions. Contractions are when the muscles of your uterus get tight and then relax. They help push your baby out of your uterus during labor and birth.

Cervical insufficiency can cause premature birth and miscarriage. Premature birth is when your baby is born too early, before 37 weeks of pregnancy. Miscarriage is when a baby dies in the womb before 20 weeks of pregnancy.

What are signs of cervical insufficiency?

If your health care provider thinks you may have cervical insufficiency, she may check you regularly during pregnancy with transvaginal ultrasound starting at 16 to 20 weeks of pregnancy. Transvaginal ultrasound is an ultrasound in the vagina, not on the outside of your belly. An ultrasound is a prenatal test that uses sound waves and a computer screen to show a picture of your baby in the womb.

If you have a cervical insufficiency, you may not have signs early on in pregnancy.  Some women may feel mild discomfort or spotting starting between 14 to 20 weeks of pregnancy.  Some other signs to look out for include:

  • A feeling of pelvic pressure
  • A new backache
  • Mild cramps in your belly (abdomen)
  • A change in vaginal discharge
  • Light vaginal bleeding

What actions can be taken with cervical insufficiency?

Your provider may recommend a cerclage. This is a stitch your provider puts in your cervix to help keep it closed. You can get a cerclage as early as 13 to 14 weeks of pregnancy, and your provider removes the stitch at about 37 weeks of pregnancy. Cerclage may be right for you if you’re pregnant now with just one baby and:

  • You had a cerclage in a past pregnancy.
  • You’ve had one or more pregnancy losses in the second trimester.
  • You had a spontaneous premature birth before 34 weeks in a past pregnancy with a cervix shorter than 25 millimeters (about 1 inch) before 24 weeks of pregnancy. Spontaneous means that labor began on its own.
  • In this pregnancy, your cervix is opening in the second trimester.

A cerclage is not recommended if you’re pregnant with twins, even if your cervix is shorter than 25 millimeters.

Some providers may also recommend taking a medication like progesterone, a hormone that may help prevent premature birth. Talk to your provider if you have questions about progesterone.

We don’t always know why cervical insufficiency happens. You’re more likely than other women to have it if:

  • You have defects in your uterus, like if it’s split into two sections.
  • You’re pregnant with more than 1 baby like twins or triplets
  • You’ve had surgery on your cervix.
  • You have a short cervix. The shorter the cervix, the more likely you are to have cervical insufficiency.
  • You’ve had Injuries to your uterus that happened during a previous birth.

What is short cervix?

A short cervix means the length of your cervix (also called cervical length) is shorter than normal. You may find out that you have a short cervix during an ultrasound that you get as part of your regular prenatal care. Prenatal care is medical care you get during pregnancy.

Checking for a short cervix is not a routine prenatal test. Your provider probably doesn’t check your cervical length unless:

If your provider thinks you have a short cervix, she may check you regularly with an ultrasound.

If you have a short cervix, you are at increased risk of having a premature birth. If you have a short cervix and you’re pregnant with just one baby, your health care provider may recommend these treatments to help you stay pregnant longer:

  • Cerclage
  • Progesterone. Progesterone is a hormone that helps prepare your body for pregnancy. It may help prevent premature birth only if you have a short cervix and you’re pregnant with just one baby.

Many things can affect the length of your cervix, including:

  • Having an overdistended (stretched or enlarged) uterus
  • Problems caused by bleeding during pregnancy or inflammation (irritation) of the uterus
  • Infection
  • Cervical insufficiency

Last reviewed January 2020