Cervical Length & Its Importance In Pregnancy

Cervical Length During Pregnancy

Medically Reviewed By
Dr. Rima Sonpal (Gynecologist/Obstetrician)
View more Gynecologist/Obstetrician Our Panel of Experts

Ensuring a healthy pregnancy is a top priority for expectant mothers, and understanding the various factors that may influence it is crucial. Among these factors, cervical length emerges as a significant consideration, as it plays a pivotal role in preventing complications during pregnancy. This article aims to provide comprehensive insights into the concept of cervical length and its potential impact on the gestation period. Monitoring cervical length during pregnancy is a routine part of prenatal care, and healthcare professionals often employ ultrasound examinations to assess it. An unusually shortened cervix during pregnancy may be an indication of an increased risk of preterm labor, prompting closer monitoring and potential interventions to safeguard both the mother and the baby.

What Is Cervical Length?

The cervix is a three-centimetre-long canal that connects the uterus to the vagina. The cervical length is simply the length of the canal, including the cervical opening. In pregnant women, the cervix needs to be of a specific length for the growth of a healthy baby.

Why Is the Cervical Length Important?

The cervix is almost inflexible until you get pregnant. Once you conceive, it becomes softer and shorter, loses muscle tone, and dilates. This is known as cervical effacement, which allows the foetus to fit inside the cervical canal while being born. However, if your cervix is too short, you may be at risk of preterm labour and all the complications that come along with premature birth.

Are Having a Short Cervix and Cervical Insufficiency Related?

No, short cervix and cervical insufficiency are totally different things. A short cervix merely refers to the length of the cervical canal. Cervical insufficiency, on the other hand, refers to the premature cervical effacement and dilation that happen when the muscles are unable to remain firm and strong. Cervical insufficiency can lead to a short cervix.

Factors That Influence the Cervical Length

Several factors influence cervical length. Some of them are:

1. Anatomy

Some women have a short cervix. That’s how their bodies are built.

2. Distended Uterus

In multiple pregnancies, the uterus stretches more than its capacity. It pushes downwards on the cervix, reducing its length.

3. Cervical Insufficiency

Cervical insufficiency or an incompetent cervix is a condition caused due to the lack of cervical muscle strength, which can influence cervical length.

How Is the Length of the Cervix Measured?

An ultrasound transvaginal scan can help to measure the cervical length. Ideally, the cervical length in the 24th week should be about 3.5 – 5 cm, whereas, at 28 weeks, it should be 3.5 – 4 cm. At 32 weeks, the cervical length is 3 – 3.5 cm. A cervix shorter than 2.5 cm increases the likelihood of preterm birth.

Is Measuring the Cervical Length a Must?

Doctors usually recommend the cervical length scan to women carrying twins or multiples or having a medical history of premature birth and miscarriage.

What Are the Risks Associated With Short Cervical Length?

Preterm birth stands out as a significant risk associated with a short cervical length. Beyond potential health challenges for the infant, premature delivery elevates the likelihood of complications such as preeclampsia, hemorrhage, and infection for the mother.

It’s essential to recognize that a shortened cervix can also be a contributing factor to cervical incompetence, characterized by premature cervical opening typically occurring in the second trimester. Cervical incompetence poses a severe threat, potentially leading to miscarriage or preterm birth if not addressed promptly.

Moreover, a reduced cervical length heightens the probability of requiring a cesarean delivery. This is attributed to the potential inadequate dilation of the shortened cervix during labor, creating difficulties for the baby to traverse the birth canal. In certain instances, opting for a cesarean delivery becomes imperative to ensure the safety and well-being of both the mother and the newborn.

Tips to Deal With a Short Cervix

Here are a few things you should do if your cervix is too short:

1. Bed Rest

Bed rest shouldn’t be compromised. Lying down prevents the uterus and the foetus from bearing down on the cervix, thus preventing it from early effacement.

Pregnant woman on bedrest

2. Cerclage

This is a minor surgery in which your doctor will stitch your cervix shut with a couple of sutures. The procedure is quick and performed under anaesthesia. It is done for women who have had prior preterm deliveries. Some doctors believe that cerclages can lead to infection and inflammation, but these can be controlled with the right medications.

3. Hormonal Treatment

In this treatment, your doctor will place the pregnancy hormone, progesterone, in the cervical area. Progesterone can help in relaxation of the uterus.

4. Pessary

A silicone device known as a pessary can be used to support the cervix, keeping it closed shut.


1. Can Cervical Length Be Improved During Pregnancy?

Cervical length in pregnancy is generally a biological characteristic and cannot be significantly altered. However, certain interventions, like progesterone supplementation or cervical cerclage, may be recommended by healthcare professionals in specific cases to address potential issues.

2. How Often Should Cervical Length Be Monitored During Pregnancy?

The frequency of cervical size during pregnancy monitoring varies based on individual risk factors and healthcare provider recommendations. Generally, healthcare professionals assess cervical length during routine ultrasound examinations, with more frequent monitoring for those at higher risk of complications.

3. What Can I Do to Maintain a Healthy Cervical Length During Pregnancy?

While cervical length is largely influenced by biological factors, maintaining overall health is essential. Following a balanced diet, staying hydrated, avoiding tobacco and illicit substances, and attending regular prenatal check-ups contribute to overall well-being. However, specific interventions for cervical length are typically determined and guided by healthcare providers based on individual circumstances.

It’s important to understand the changes your body goes through during pregnancy. Cervical length plays a major role during pregnancy, so it is essential to stay informed about it. Do not worry if you have a normal cervical length in pregnancy. If you have any concerns about the cervical length during pregnancy, consult your gynaecologist.


1. FAQs: Preterm Labor and Birth; The American College of Obstetricians and Gynecologists; https://www.acog.org/womens-health/faqs/Preterm-Labor-and-Birth

2. Conde-Agudelo. A, Romero. R; Vaginal progesterone to prevent preterm birth in pregnant women with a sonographic short cervix: clinical and public health implications (American Journal of Obstetrics & Gynecology); National Library of Medicine; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5703061/; October 2015

3. Thakur. M, Mahajan. K; Cervical Insufficiency; National Library of Medicine; https://www.ncbi.nlm.nih.gov/books/NBK525954/

4. Wang. S, Ma. L, Huang. S, Liang. L, Zhang. J; Role of Cervical Cerclage and Vaginal Progesterone in the Treatment of Cervical Incompetence with/without Preterm Birth History (Chinese Medical Journal); National Library of Medicine; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5126157/; November 2016

5. Meng. L, Öberg. S, Sandström. A, Wang. C, Reilly. M; Identification of risk factors for incident cervical insufficiency in nulliparous and parous women: a population-based case-control study; BMC Medicine; https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-022-02542-7; October 2022

6. During pregnancy, what’s the significance of cervical length?; Mayo Clinic; https://www.mayoclinic.org/healthy-lifestyle/pregnancy-week-by-week/expert-answers/cervical-length/faq-20058357

7. Thangaraj. J, Habeebullah. S, Samal. S, Amal. S; Mid-Pregnancy Ultrasonographic Cervical Length Measurement (A Predictor of Mode and Timing of Delivery): An Observational Study; (Journal of Family and Reproductive Health); National Library of Medicine; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6329997/; March 2018

Also Read

Cervical Position in Pregnancy
Can you get Pregnant with Small Uterus
A Guide to Cervix Dilation During Labour and Birth

Previous article «
Next article »