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Key takeaways

• Preterm labour is when labour starts before 37 weeks of pregnancy.
• Seek urgent medical advice if you have signs like regular contractions or bleeding.
• Screening for preterm birth usually involves a vaginal ultrasound scan.
• Preventative treatments include vaginal progesterone or a cervical stitch.

What is preterm labour?

Preterm labour, also called premature labour, is when you go into labour before 37 weeks of pregnancy. Premature birth is when your baby is born before 37 weeks of pregnancy.

You may experience several signs and symptoms if you are going into preterm labour. These can include regular contractions, which are your womb tightening and relaxing. You might also feel abdominal cramping or pain.

Other signs include pressure in your vaginal area or period-type pains. A 'show' can occur when the mucus plug that sealed your cervix comes away. This may be a sticky, jelly-like blob, sometimes with streaks of pinkish or brown blood. You might notice a gush or trickle of fluid from your vagina, which could mean your waters are breaking. Backache that is not usual for you and comes and goes can also be a sign. Vaginal bleeding is another symptom to watch for.

When to seek immediate medical advice

Call your hospital maternity unit or midwife straight away if you are less than 37 weeks pregnant and have any of the signs and symptoms described above. If you are unsure or worried about anything, always call your midwife or maternity unit. It's important to get checked if you think your waters have broken, as there is a small risk of infection for your baby.

Another urgent reason to call is if you notice a change or reduction in your baby's movements. They will usually tell you to go straight to the hospital.

Who is at risk for preterm birth?

Several factors can increase your risk of preterm labour and birth. If you have given birth preterm before, you are more likely to do so again. The risk increases with more premature deliveries or earlier births. Your risk is also higher if you have had a miscarriage after 16 weeks pregnant in the past.

Being pregnant with more than one baby, such as twins, also increases the risk. This can be due to natural early labour or a healthcare team recommendation for an early birth.

If the neck of your womb (the cervix) is not as strong as usual (called cervical incompetence or insufficiency) is another risk factor. This can cause the cervix to shorten and open too soon in pregnancy. Previous preterm birth or miscarriage can increase this risk.

Treatments to your cervix can also make you more at risk. This includes past treatments for abnormal cells on your cervix usually identified during your smear (such as a LLETZ or a cone biopsy).

Some people have a womb that is different in shape or size (a uterine abnormality). This can also increase the risk of premature birth.

Screening for preterm birth in the UK

You may be offered screening to assess your risk of preterm labour. Your midwife will assess this at your first booking appointment. A thorough assessment which will include going over the risks described above, will help determine if you would benefit from extra monitoring.

If you are offered extra monitoring this will usually be offered a vaginal ultrasound scan between 16 and 24 weeks of pregnancy.

How screening is done

This ultrasound scan measures the length of your cervix. A cervix shorter than 25mm has been linked to a higher risk of early labour and birth. This measurement helps your healthcare team decide if treatment may be helpful.

Preventative treatments to reduce risk

If you are at higher risk of preterm birth, your doctor or midwife may offer preventative treatments. Treatment usually starts before 24 weeks of pregnancy. Your treatment may depend on your specific risk factors and previous pregnancy history.

You may be offered a choice between a cervical stitch or vaginal progesterone. At the moment, there is no clear evidence that one treatment is better than the other.

Your midwife or doctor will discuss the risks and benefits with you. Your circumstances and preferences are important in deciding the best treatment.

Vaginal progesterone

Treatment with vaginal progesterone involves regularly putting a progesterone pessary into your vagina. This is usually done up until 34 weeks of pregnancy. The pessary is shaped like a small tampon, and most people find it easy to use.

Progesterone is a hormone that supports pregnancy in several ways. It helps keep the womb relaxed and lowers the risk of early labour. While this treatment can be very helpful, it's good to be aware that it doesn't prevent preterm labour in every case.

Cervical stitch (cerclage)

This is a surgical procedure where stitches are placed around the cervix to help it stay closed during pregnancy. This extra support can reduce your risk of having a preterm birth. There are risks involved with this procedure and this will be discussed with you if this is a treatment option for you.

Most people have the stitch put in through the vagina. It is usually a planned procedure done between 11 and 24 weeks of pregnancy. The procedure takes place in an operating theatre.

You may have a spinal anaesthetic, which means you stay awake but are numb from the waist down. Alternatively, you might have a general anaesthetic, where you are asleep. The stitch is removed before you have your baby. This usually happens at 36 to 37 weeks, unless you go into labour sooner.

If you are having a planned caesarean, the stitch can be taken out at that time. It's important to know that while a stitch can be very effective, it doesn't always prevent a preterm birth.

A cervical stitch cannot be done if you have:

• vaginal bleeding
• signs of infection
• broken waters
• contractions

Emergency or alternative stitches

An emergency cervical stitch may be offered if your cervix has started to open between 16 and 28 weeks. Your care team will explain that an emergency stitch has different risks and success rates compared to a planned one. It may still be the best option for you.

A transabdominal cervical stitch may be offered if a previous vaginal stitch was not successful or after extensive cervical surgery. This type of stitch is not removed, and you would need to have your baby by caesarean section.