Medical Conditions

Cervical Insufficiency

Content reviewed against published ACOG, March of Dimes, Mayo Clinic guidelines

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If your baby has been diagnosed with or you suspect cervical insufficiency, here is what the evidence says.

The short answer

Cervical insufficiency (previously called incompetent cervix) occurs when the cervix begins to open too early in pregnancy, often without pain or contractions. It is a leading cause of second-trimester pregnancy loss but is treatable. With early detection through cervical length screening and interventions such as cerclage or progesterone, most women with cervical insufficiency carry their pregnancies to a viable gestational age.

Key takeaways

  • Cervical insufficiency (previously called incompetent cervix) occurs when the cervix begins to open too early in pregnancy, often without pain or contractions. It is a leading cause of second-trimester pregnancy loss but is treatable. With early detection through cervical length screening and interventions such as cerclage or progesterone, most women with cervical insufficiency carry their pregnancies to a viable gestational age.
  • Usually normal when: Your cervical length is above 25mm on transvaginal ultrasound in the second trimester
  • Call your doctor if: You experience a sensation of something bulging in your vagina, or your membranes rupture before 37 weeks
  • Varies by age — see the age-by-age breakdown below
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By Age

What to expect by age

First trimester

Cervical insufficiency is typically not detectable in the first trimester. However, if you have risk factors such as a history of second-trimester loss, prior cervical surgery (LEEP, cone biopsy), or a connective tissue disorder, your provider should be informed early. A history-indicated cerclage may be placed around 12-14 weeks if you have had multiple prior losses due to cervical insufficiency.

Second trimester

The second trimester is when cervical insufficiency most commonly becomes apparent, typically between 16-24 weeks. Transvaginal ultrasound to measure cervical length is the primary screening tool. A cervix shorter than 25mm before 24 weeks may warrant intervention. Treatments include vaginal progesterone, cervical pessary, or surgical cerclage. You may notice pelvic pressure, increased discharge, or spotting - report these promptly.

Third trimester

If cervical insufficiency was managed with cerclage, the stitch is typically removed around 36-37 weeks to allow for normal labor. If you are on vaginal progesterone, it is usually discontinued around the same time. By the third trimester, the risk from cervical insufficiency is lower because the baby has reached viability. Your provider will continue to monitor for signs of preterm labor.

Postpartum

After delivery, discuss your experience with your provider to plan for future pregnancies. If you had cervical insufficiency in one pregnancy, you are at higher risk in subsequent pregnancies. A proactive management plan including early cerclage or serial cervical length screening starting at 16 weeks is typically recommended for future pregnancies.

What Should You Do?

When to take action

Probably normal when...
  • Your cervical length is above 25mm on transvaginal ultrasound in the second trimester
  • You had a LEEP or cone biopsy in the past but your cervix is measuring normally during pregnancy
  • You have mild pelvic pressure that is intermittent and not worsening
  • Your provider is monitoring your cervical length and has not recommended intervention
Mention at your next visit when...
  • You have a history of second-trimester pregnancy loss or very preterm birth without a known cause
  • You notice a significant increase in vaginal discharge, pelvic pressure, or mild spotting before 24 weeks
  • You have had cervical surgery and want to discuss monitoring during your pregnancy
Act now when...
  • You experience a sensation of something bulging in your vagina, or your membranes rupture before 37 weeks
  • You have regular contractions, progressive pelvic pressure, or vaginal bleeding in the second trimester

Doctor Visit Checklist

Bring this checklist to your next pediatrician visit to discuss Cervical Insufficiency.

Things to mention

  • You have a history of second-trimester pregnancy loss or very preterm birth without a known cause
  • You notice a significant increase in vaginal discharge, pelvic pressure, or mild spotting before 24 weeks
  • You have had cervical surgery and want to discuss monitoring during your pregnancy

Observations to share

  • You have a history of second-trimester pregnancy loss or very preterm birth without a known cause
  • You notice a significant increase in vaginal discharge, pelvic pressure, or mild spotting before 24 weeks
  • You have had cervical surgery and want to discuss monitoring during your pregnancy

Urgent signs to report immediately

  • You experience a sensation of something bulging in your vagina, or your membranes rupture before 37 weeks
  • You have regular contractions, progressive pelvic pressure, or vaginal bleeding in the second trimester

My notes

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Frequently asked questions

Is cervical insufficiency normal?
Cervical insufficiency (previously called incompetent cervix) occurs when the cervix begins to open too early in pregnancy, often without pain or contractions. It is a leading cause of second-trimester pregnancy loss but is treatable. With early detection through cervical length screening and interventions such as cerclage or progesterone, most women with cervical insufficiency carry their pregnancies to a viable gestational age.
When should I call the doctor about cervical insufficiency?
You experience a sensation of something bulging in your vagina, or your membranes rupture before 37 weeks You have regular contractions, progressive pelvic pressure, or vaginal bleeding in the second trimester
When is cervical insufficiency normal?
Your cervical length is above 25mm on transvaginal ultrasound in the second trimester You had a LEEP or cone biopsy in the past but your cervix is measuring normally during pregnancy You have mild pelvic pressure that is intermittent and not worsening
What causes cervical insufficiency?
Cervical insufficiency (previously called incompetent cervix) occurs when the cervix begins to open too early in pregnancy, often without pain or contractions. It is a leading cause of second-trimester pregnancy loss but is treatable. With early detection through cervical length screening and interventions such as cerclage or progesterone, most women with cervical insufficiency carry their pregnancies to a viable gestational age. Common explanations include: Your cervical length is above 25mm on transvaginal ultrasound in the second trimester. You had a LEEP or cone biopsy in the past but your cervix is measuring normally during pregnancy.
What should I mention to my pediatrician about cervical insufficiency?
You should mention cervical insufficiency at your next visit if: You have a history of second-trimester pregnancy loss or very preterm birth without a known cause. You notice a significant increase in vaginal discharge, pelvic pressure, or mild spotting before 24 weeks. You have had cervical surgery and want to discuss monitoring during your pregnancy.
Is cervical insufficiency normal at First trimester?
Cervical insufficiency is typically not detectable in the first trimester. However, if you have risk factors such as a history of second-trimester loss, prior cervical surgery (LEEP, cone biopsy), or a connective tissue disorder, your provider should be informed early. A history-indicated cerclage may be placed around 12-14 weeks if you have had multiple prior losses due to cervical insufficiency.
Is cervical insufficiency normal at Second trimester?
The second trimester is when cervical insufficiency most commonly becomes apparent, typically between 16-24 weeks. Transvaginal ultrasound to measure cervical length is the primary screening tool. A cervix shorter than 25mm before 24 weeks may warrant intervention. Treatments include vaginal progesterone, cervical pessary, or surgical cerclage. You may notice pelvic pressure, increased discharge, or spotting - report these promptly.
Should I go to the ER for cervical insufficiency?
Seek emergency care if you experience a sensation of something bulging in your vagina, or your membranes rupture before 37 weeks, or if you have regular contractions, progressive pelvic pressure, or vaginal bleeding in the second trimester. When in doubt, call your pediatrician's after-hours line for guidance.
Does cervical insufficiency go away on its own?
In many cases, cervical insufficiency resolves on its own, especially when your cervical length is above 25mm on transvaginal ultrasound in the second trimester. By Postpartum, after delivery, discuss your experience with your provider to plan for future pregnancies. If you had cervical insufficiency in one pregnancy, you are at higher risk in subsequent pregnancies. A proactive management plan including early cerclage or serial cervical length screening starting at 16 weeks is typically recommended for future pregnancies.
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References

  1. [1]American College of Obstetricians and Gynecologists. Cerclage for the Management of Cervical Insufficiency. ACOG Practice Bulletin No. 234, 2021. ACOG
  2. [2]March of Dimes. Cervical insufficiency and short cervix. March of Dimes, 2023. March of Dimes
  3. [3]Mayo Clinic. Incompetent cervix - Symptoms and causes. Mayo Clinic, 2023. Mayo Clinic

All content follows our editorial policy and is reviewed against published clinical guidelines.

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Bottom line

Most cases of cervical insufficiency are normal. Talk to your pediatrician if you experience a sensation of something bulging in your vagina, or your membranes rupture before 37 weeks.

Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.

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