Cervical Scan

A cervical scan is a transvaginal ultrasound used to measure the length of the cervix during pregnancy. It helps assess the risk of preterm birth and is especially important for women with certain risk factors such as a history of early delivery, cervical surgery, uterine abnormalities, or multiple pregnancies.

By identifying concerns early, this scan allows doctors to recommend treatment or monitoring that can help reduce the chance of premature labour.

Why is a cervical scan important?

The cervix is vital in maintaining a pregnancy. If it shortens or begins to open too early, there is a greater risk of preterm birth. A cervical scan is recommended if you:

Have had a previous preterm birth, particularly before 34 weeks
Have undergone cervical surgery (such as LLETZ or cone biopsy)
Are carrying twins or a multiple pregnancy
Have a uterine abnormality (bicornuate, didelphic, septate, etc.)
Have experienced pregnancy loss in the second trimester
Had a caesarean section performed at full dilatation

Measuring cervical length at the right time can highlight problems early, so steps can be taken to help reduce risks.

When is a cervical scan performed?

Typically between 16 and 24 weeks of pregnancy
In high-risk cases, scans may be repeated every 2–3 weeks, starting from 16 weeks, depending on your individual circumstances

How is the cervical scan performed?

The scan is done transvaginally (through the vagina), which provides the most accurate measurement
It takes only a few minutes and is not painful
A slim ultrasound probe is gently inserted to view the cervix in detail
You’ll be asked to empty your bladder beforehand for comfort and clearer results

What do the results mean?

A normal cervical length is 25mm or more
If the cervix measures less than 25mm, treatment options may include:
- Progesterone therapy (vaginal pessaries)
- Cervical stitch (cerclage)
- More frequent monitoring

All findings will be explained during your appointment, and recommendations will be tailored to your personal history and results.

What should I expect after the scan?

Duration: The scan itself takes about 5 minutes; the full appointment usually lasts around 30 minutes to allow time for discussion.
Results: You’ll receive a printed report and images on the same day, with a copy sent to your referring doctor (if details are provided).
Images: Printed 2D images of the cervical length are included at no extra cost.
Second opinion: If you’re attending for a second opinion, please bring or send your previous reports in advance.