What is a cervical length scan?
An ultrasound measurement of the cervix, the neck of the womb, taken in the middle of pregnancy. A cervix that is shorter than expected is linked to a higher chance of preterm birth, and measuring it lets your maternity team act early. It is done transvaginally, because that is the accurate way to measure it.
Who needs a cervical length scan?
It is recommended for women who
- Have had a previous preterm birth or late miscarriage
- Have had treatment to the cervix, such as a LLETZ or cone biopsy
- Are carrying twins or triplets
- Have a cervical stitch in place
- Had a question raised about the cervix at the anomaly scan
Some women book simply for the reassurance of a measurement.
When should the cervix be measured?
Between 16 and 24 weeks, when a short cervix matters most and when treatment makes a difference. If monitoring is advised, the measurement is usually repeated every one to two weeks until about 24 weeks.
Why is the scan transvaginal?
Because the cervix sits deep in the pelvis, a scan through the tummy cannot measure it reliably. The transvaginal scan takes a few minutes, is not painful and is performed by a female sonographer with a sheet provided. You need an empty bladder.
What is a short cervix?
A closed cervical length under 25 millimetres before 24 weeks is the usual definition. The shorter the cervix, and the earlier it is found, the higher the risk of an early birth. Your sonographer explains your measurement in context.
What is funnelling?
When the inner end of the cervix, next to the womb, starts to open while the outer end stays closed. It is seen on the scan as a V or U shape. Funnelling can raise the risk even when the remaining closed length is normal, which is why it is reported alongside the measurement.
What happens if my cervix is short?
Your sonographer explains the finding, a consultant is available on the day, and your maternity team receives the report the same day. The usual options are vaginal progesterone, a cervical stitch, called a cerclage, or closer monitoring with repeat scans, decided with your obstetrician.
Can a cervical length scan check a cervical stitch?
Yes. If you have a cerclage in place, the scan shows its position and measures the cervix above and below it, which is how the stitch is monitored through the pregnancy.
Is the scan safe for my baby?
Yes. It is a standard ultrasound examination used throughout pregnancy, with no radiation. The probe stays in the vagina and does not reach the baby or the inside of the womb.
How long does a cervical length scan take?
About 20 minutes in total. The measurement takes a few minutes, and the rest is the conversation beforehand and the explanation of your result.
Can a short cervix get longer or be treated?
The length itself rarely increases, but the risk it carries can be reduced. Vaginal progesterone, a cervical stitch and closer monitoring are the established options, chosen with your obstetrician according to your history and the measurement. Many women with a short cervix go on to deliver at term.
Will the NHS measure my cervix?
If you have a known risk factor, your NHS maternity team may arrange cervical length monitoring. If you are not being monitored and would like certainty, a private measurement with a written report never affects your NHS care, and the report goes to your maternity team the same day.
How much does a cervical length scan cost in London?
A private cervical length scan at Harley Street Ultrasound costs £200, fixed and all-inclusive. The scan, your sonographer’s time, scan images and the written report. Book online or call 0203 904 4441, no referral needed.
What if something needs a closer look?
Your sonographer tells you in the room, gently and in plain English, and explains exactly what it means. You are never sent home to wait for a letter. Most of the time a finding simply needs a repeat scan in a week or two, or a measurement checked again at the next routine scan.
If something genuinely needs attention, a consultant review is available the same day, and we arrange the next step for you: a referral to a fetal medicine specialist or early pregnancy unit, with your report and images, through our hospital partners. You will not be left alone with a worry.
Do I need a referral?
No. Harley Street Ultrasound is a private clinic, so you can book a cervical length scan in London directly online or by phone, with no GP or midwife letter and no waiting list. Same-day and next-day appointments are usually available, and we are at 99 Harley Street, a short walk from Regent’s Park and Oxford Circus stations.
The price is published before you book: £200, all fees inclusive, covering the scan, your sonographer’s time, your scan images and your written report. Pregnancy scans are usually self-pay; if you are insured, check whether your policy covers pregnancy scanning before you book.
How soon will I have the written report?
The same day. You will already know what was seen, because your sonographer explains everything on screen as the scan happens, and your written report is published to your secure patient portal with your images before the day ends, ready to share with your midwife, GP or consultant.
Your scan images are on your secure portal the same day.
Is ultrasound safe for my baby?
Yes. Ultrasound uses sound waves, not radiation, and has been used in pregnancy for more than fifty years with no confirmed harmful effects on babies. Our sonographers keep scan times to what is clinically needed and use hospital-grade equipment, so a scan can be repeated safely whenever it is useful.
Can I still have my NHS scans afterwards?
Yes, completely. A private scan with us never affects your NHS maternity care: keep every NHS appointment as planned. Many parents book with us for extra reassurance between NHS scans, or for a scan the NHS does not routinely offer. If anything needs attention, your sonographer writes to your midwife or GP so that you re-enter the NHS pathway with the findings already in hand.
