Tommy's PregnancyHub

Premature birth

A ’premature’ or ’preterm’ baby is one that is born before 37 weeks. If your baby is born early they may need special care as they may not be fully developed.

What is premature birth?

The definition of a 'premature' or 'preterm' baby is one that is born before 37 weeks. There are different categories levels of prematurity and these carry their own risks:

  • Extremely preterm (less than 28 weeks)
  • very preterm (28 to 32 weeks)
  • moderate to late preterm (32 to 37 weeks).

What are the symptoms of premature birth?

The following symptoms before 37 weeks of pregnancy could be signs that you are about to go into labour:

  • an increase in pelvic pressure within the vagina or rectum.
  • an increase in discharge and/or a gush/repeat trickling of fluid, which could mean your waters have broken (preterm premature rupture of membranes).
  • bleeding or losing your mucus plug.
  • period type pains in your abdomen or lower back. These may have a rhythm or be constant.

If you have these symptoms contact your hospital.

Read more about the signs of premature labour here.

Read more about being told you are at risk of premature birth here.

What is the treatment for premature birth?

If a pregnancy is found to be at high risk of premature birth, the mother is treated to extend the pregnancy as far as possible. There are various ways this is done.

Read about treatment for a pregnancy that is at high risk of premature birth here. 

Read about treating your premature baby in hospital after they are born here.

How common is premature birth?

In the UK, around 60,000 babies are born prematurely each year. The rate of preterm birth is between 7-8% across the UK.

Read more premature birth statistics.

To talk to other parents of premature babies, visit BabyCentre’s friendly prematurity support group.

What are the causes of premature birth?

In some cases a cause of preterm birth can be shown but more often it is unknown or unclear. Complications, such as infection or cervical incompetence increase the risk. Women who are having a multiple pregnancy (twins, triplets or more) are also have a higher chance of giving birth prematurely. The average length of pregnancy for twins is 37 weeks, and 33 weeks for triplets. 

In 25% of preterm births, the delivery is planned because the mother and/or baby are suffering life-threatening complications such as pre-eclampsia, kidney disease or growth restriction.

Read more about the causes of premature birth.

Why is premature birth a problem?

During the nine months of pregnancy babies' bodies are developing in the womb to allow them to survive and thrive when they are born. When a baby is born too soon, some parts of their development will not have been finished and this means they are not ready for life outside the womb.

Luckily advances in neonatal care have come on greatly and neonatal units, special care units and paediatricians are equipped to support the baby until their bodies strengthen and develop fully.

However, the earlier a baby is born the higher the risk is of health problems. There are different levels of prematurity, and generally the risk increases the earlier the birth is - babies at highest risk are those born before week 26.

Read more about the effects of premature birth.

  1. WHO (2012) Country data and rankings for preterm birth 2012, World Health Organisation, Geneva, Switzerland,
  2. WHO (2012) Country data and rankings for preterm birth 2012, World Health Organisation, Geneva, Switzerland,
  3. NHS Choices [accessed 10/01/2018] Premature labour and birth,
  4. NICE (2013) Preterm labour and birth scope 2013, National Institute for Health and Care Excellence, London, England,
Review dates

Last reviewed: 1 April 2017
Next review: 1 April 2020