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Most babies are born between 37 and 42 weeks of pregnancy. If a baby is born before 37 weeks, this is called a preterm (premature) birth. About 8 out of every 100 babies are born early.
Babies born early can have more health problems and may need care in a neonatal unit (a special ward for sick or early babies). Usually, the earlier a baby is born, the longer they stay in this unit.
Sometimes babies come early for reasons we don’t know. But there are some things that can make early birth more likely. This clinic gives extra care to women who have these risks, to help prevent early birth.
You may be asked to come to this clinic if you have a higher chance of having your baby early. Some reasons include:
- you had a baby early before (between 24 and 34 weeks) after going into labour naturally.
- your waters broke on their own before 34 weeks in a past pregnancy.
- you lost a baby between 16 and 24 weeks of pregnancy.
- you have a uterus that is a different shape or size (bicornuate, septate, unicornuate or didelphys uterus).
- you had surgery on your cervix called ‘LLETZ’ or ‘cone biopsy’ where more than 15mm was removed (or if we don’t know how much was removed). This is not the same as colposcopy and punch biopsy.
- you have scar tissue inside your uterus (called Asherman’s Syndrome).
- you had an operation called radial trachelectomy for cancer of the cervix.
- you gave birth by caesarean section when your cervix was fully open (10cm).
- you had a cervical stitch (cerclage) in a past pregnancy.
Having one or more of these does not mean you will have your baby early. It just means the risk is a little higher. If you don’t think you have any of these but have an appointment, please call:
Frimley Park Hospital: 0300 614 5000
Wexham Park Hospital: 0300 615 4513
This clinic is run by a consultant obstetrician (a doctor who looks after pregnancy) and a specialist midwife. They will give you care and support based on your needs. Some women come for their first visit at 14 weeks, others at 18 weeks. Some only need one visit, others need more. The doctor and midwife will talk to you about what is best.
You will meet someone from the preterm birth team. They will talk to you about your own risk factors and ask about your health and past pregnancies.
You will be offered a transvaginal scan. This is an internal scan where a small probe is gently put inside your vagina to measure the length of your cervix (the neck of the womb). The length of your cervix helps us understand how likely it is that you might have your baby early.
You will be asked to go to the toilet first because the scan needs to be done when your bladder is empty. Some women worry about this type of scan, but it is usually not painful and is very safe during pregnancy. It will not harm you or your baby.
You can have a chaperone (someone to stay with you) during the scan, and your partner can come too if you wish. If you feel very nervous about the scan, please tell the team so they can give you extra support.
The scan will be done by either the consultant obstetrician or someone from the ultrasound team. There are both female and male staff, and they are specially trained to do this type of scan.
You may also be asked to give a urine sample and have a vaginal swab to check for infections.
Most women will not need any treatment. If your scan shows your cervix is a normal length and the chance of early birth is low, you will not need more visits to this clinic. You may still see a consultant for other reasons or go back to midwife-led care.
Some women will need more scans during pregnancy to check the cervix length. In some cases, the consultant may suggest treatment, such as:
- a pessary with the hormone progesterone
- a cervical stitch (called a cerclage) to help keep the cervix closed
You may have already had these treatments early in pregnancy and are coming to the clinic just for checks.
It can be hard to know who will go into labour early, and sometimes it happens without warning. If you have any of these symptoms, call MAMAS line 0300 013 2004 straight away and tell them you are at risk of preterm labour and are under the care of the Preterm birth prevention and surveillance clinic:
- regular painful tightenings or contractions of your uterus
- cramps like strong period pains
- feeling pressure in your vaginal area
- a ‘show’ – when the mucus plug from your cervix comes out
- a leak or gush of fluid from your vagina
- unusual backache
- bleeding from your vagina
Contact us
If you have any queries relating to this information, please contact the Maternity service.
About this information
Service:
Maternity
Reference:
M/020
Approval date:
1 March 2026
Review date:
1 March 2029
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Important note
This page provides general information only. It is developed by clinical staff and is reviewed regularly every 3 years for accuracy. For personal advice about your health, or if you have any concerns, please speak to your doctor.