Need to talk? Call 1800 882 436.
It's a free call with a maternal child health nurse. *call charges may apply from your mobile

Is it an emergency? Dial 000
If you need urgent medical help, call triple zero immediately.

beginning of content

Short cervix in pregnancy

7-minute read

Key facts

  • The cervix is part of the female reproductive system and is found at the lower part of the uterus connecting to the vagina.
  • A short cervix during pregnancy increases the chance of having a preterm (early) birth.
  • Risk factors associated with having a short cervix include previously having a preterm birth or previously having a procedure on your cervix where a part of your cervix was removed.
  • A short cervix is diagnosed using ultrasound.
  • A short cervix can be managed during pregnancy with rest, progesterone medicine or a procedure called cervical cerclage.

What is the cervix?

The cervix is part of the female reproductive system and may be referred to as the ‘neck’ of your uterus. It is a muscular channel that connects the body of your uterus with your vagina. The cervix is usually around 3cm long and is made up of a central channel with an internal and external opening. It plays an important role in conception (becoming pregnant) and pregnancy. Your cervix makes mucus that helps to transport sperm from the vagina. It also keeps the uterus closed during pregnancy. During labour, the cervix relaxes and slowly opens.

What does it mean to have a short cervix during pregnancy?

The length of your cervix during pregnancy relates to the chance of you having a preterm (early or premature) birth. A short cervix is one that is less than 25mm (2.5cm) long at around 20 weeks of pregnancy. The shorter your cervix, the higher the risk of an early birth (earlier than 37 weeks pregnancy).

Most women with a short cervix still give birth on time, but if you have a higher-than-average risk of having your baby early, it is important to know this ahead of time, before labour begins, so that you and your health team can be prepared. Your health team may also suggest treatments to help reduce this risk.

Diagram showing the female reproductive system.
Illustration showing the female reproductive system.

Some hospitals or clinics measure cervical length routinely at around 20 weeks of pregnancy. Other places only measure cervical length if you have risk factors for preterm birth or if you have particular symptoms such as preterm contractions.

Are there risk factors for having a short cervix?

There are some risk factors linked with having a short cervix.

These risk factors include:

  • previous preterm birth
  • previous procedure on your cervix in which a small part of your cervix was removed
  • previous cervical trauma including cervical tearing during labour or dilation and curettage (D&C)

How is a short cervix diagnosed?

A short cervix can be diagnosed using ultrasound.

Your doctor may do a transabdominal ultrasound (an ultrasound done on your tummy) in the middle of your pregnancy if you are at low risk of having a short cervix and have a singleton pregnancy (a pregnancy with one baby in your uterus). If your cervix is shorter than expected on the transabdominal ultrasound or your doctor has difficulty seeing your cervix properly on the transabdominal ultrasound, they may suggest doing a transvaginal ultrasound (an ultrasound done internally, through your vagina). The cervix can be seen better on a transvaginal ultrasound.

If you are at a high risk of having a short cervix, your doctor may suggest doing a transvaginal ultrasound to see your cervix more clearly and to measure the length of your cervix more accurately.

How is a short cervix managed during pregnancy?

There are different approaches to managing a short cervix during pregnancy. Your doctor may suggest using progesterone to reduce the risk of preterm birth. This medication can be given in the form of a small progesterone tablet, placed directly into your vagina or anus (bottom).

Cervical cerclage is another technique to help prevent pre-term labour that occurs because of a short cervix. It involves minor surgery that places a stich in the cervix. Your doctor may suggest this treatment if you have a singleton pregnancy and have a short cervix. Cervical cerclage is often recommended if you have previously had a premature birth or a pregnancy loss during your second trimester, or if your cervix continues to get shorter despite using progesterone daily. Your health team may also recommend this procedure if your cervix is very short (less than 10mm) in the second trimester.

In some cases, bed rest and admission to the hospital may also be recommended.

Are there risks to me or my baby if I have a short cervix?

While most women with a short cervix give birth on time, they are more likely to give birth early. Premature birth is the leading cause of newborn morbidity (illness) and mortality (death) worldwide. Premature birth can also lead to long-term health problems later in life. For this reason, it’s best to have a short cervix diagnosed early, so that you can be treated and monitored, and take steps towards preventing a premature birth.

Resources and support

As well as asking your doctor or nurse for advice, you can get help and information from:

Speak to a maternal child health nurse

Call Pregnancy, Birth and Baby to speak to a maternal child health nurse on 1800 882 436 or video call. Available 7am to midnight (AET), 7 days a week.

Learn more here about the development and quality assurance of healthdirect content.

Last reviewed: January 2023


Back To Top

Need more information?

Anatomy of pregnancy and birth - cervix

Your cervix goes through many changes during pregnancy and childbirth. Find out about your cervix, what it does and why it’s important.

Read more on Pregnancy, Birth & Baby website

Anatomy of pregnancy and birth - perineum and pelvic floor

Read about your pelvic floor, including your perineum, which lies across the bottom of your pelvis and can be damaged during pregnancy and childbirth.

Read more on Pregnancy, Birth & Baby website

Preterm labour - MyDr.com.au

Going into labour before your 37th week of pregnancy is called preterm labour, or premature labour. Find out what it means for you and your baby.

Read more on myDr website

Exercising during pregnancy

Physical activity while pregnant can help prepare your body for childbirth. Learn more about what exercises you can do, and what activities to avoid.

Read more on Pregnancy, Birth & Baby website

Treatment of Preterm Labour - Miracle Babies

It is difficult to prevent preterm labour for there are times when it is unavoidable and indeed necessary to deliver a baby

Read more on Miracle Babies Foundation website

Testing for miscarriage - Miscarriage Australia

In Australia, testing for the cause of miscarriage is not generally offered unless you have experienced 3 or more miscarriages in a row.

Read more on Miscarriage Australia website

Recurrent miscarriage - Miscarriage Australia

Recurrent miscarriage is defined as 3 or more miscarriages in a row. Around 1-2% of women experience recurrent miscarriage.

Read more on Miscarriage Australia website

Antenatal expression of colostrum

Colostrum, the first breast milk, is high in antibodies. It can be expressed before you give birth. Learn if expressing colostrum is right for you.

Read more on Pregnancy, Birth & Baby website

Episiotomy

An episiotomy is a procedure performed during labour to assist with the delivery of your baby.

Read more on Pregnancy, Birth & Baby website

Labour & birth: what to expect | Raising Children Network

Early labour signs include a show, waters breaking and pain. During labour, your contractions increase and your cervix dilates, so you can birth your baby.

Read more on raisingchildren.net.au website

Call us and speak to a Maternal Child Health Nurse for personal advice and guidance.

Need further advice or guidance from our maternal child health nurses?

Healthdirect Australia acknowledges the Traditional Owners of Country throughout Australia and their continuing connection to land, sea and community. We pay our respects to the Traditional Owners and to Elders both past and present.

This information is for your general information and use only and is not intended to be used as medical advice and should not be used to diagnose, treat, cure or prevent any medical condition, nor should it be used for therapeutic purposes.

The information is not a substitute for independent professional advice and should not be used as an alternative to professional health care. If you have a particular medical problem, please consult a healthcare professional.

Except as permitted under the Copyright Act 1968, this publication or any part of it may not be reproduced, altered, adapted, stored and/or distributed in any form or by any means without the prior written permission of Healthdirect Australia.