A preterm birth is one that happens before 37 completed weeks of pregnancy.
The World Health Organisation gives the following definitions for the different stages of preterm birth:
- Extremely preterm: before 28 weeks
- Very preterm: from 28 to 32 weeks
- Moderate to late preterm: from 32 to 37 weeks.
General UK premature birth statistics
- Around 7% of births in the UK are preterm. That is 60,000 babies each year
- This is higher than many countries in Europe and higher than Cuba, Ecuador and Iraq
Of the births that were preterm in the UK:
- 5% were extremely preterm (before 28 weeks)
- 11% were very preterm (between 28 and 32 weeks)
- 85% were moderately preterm (between 32 and 37 weeks).
Medical advances mean that we are getting better at treating preterm babies but the chances of survival still depend on gestational age (week of pregnancy) at time of birth.
- Less than 22 weeks is close to zero chance of survival
- 22 weeks is around 10%
- 24 weeks is around 60%
- 27 weeks is around 89%
- 31 weeks is around 95%
- 34 weeks is equivalent to a baby born at full term.
Preterm birth and neonatal death
Complications arising from premature birth is the leading cause of neonatal death (death in the first few weeks after birth) in the UK.
Having more than one baby is a risk factor for preterm birth. On average, most singleton pregnancies last 39 weeks, twin pregnancies 37 weeks and triplets 33 weeks.
- Risk of prematurity with singleton pregnancy: 7%
- Risk of prematurity with multiple pregnancy: 57%
Risk of disability in preterm children
Generally, the earlier the birth, the higher the risk of problems. However these are only statistics and cannot predict how an individual child will do; some extremely premature babies do very well and develop into healthy children.
- 1 in 10 of all premature babies will have a permanent disability such as lung disease, cerebral palsy, blindness or deafness.
- 1 in 2 of premature babies born before 26 weeks of gestation will have some sort of disability (this includes mild disability such as requiring glasses).
In one study of 241 children born before 26 weeks' gestation the following was found:
- 22% severe disability (eg cerebral palsy + not walking, low cognitive scores, blindness, profound deafness)
- 24% moderate disability (eg cerebral palsy + walking, IQ/cognitive scores in the special needs range, lesser degree of visual or hearing impairment)
- 34% mild disability (defined as low IQ/cognitive score, squint, requiring glasses)
- 20% no problems.
The risk of preterm birth is highest for Black Caribbean women and lowest for White British and White Other.
- Bangladeshi: 8%
- Indian: 7%
- Black African: 8%
- Black Caribbean: 10%
- White British: 7%
- White Other: 6%
Causes of preterm birth
In some cases a cause of preterm birth can be shown but more often it is unknown or unclear.
In 1 in 4 preterm births, the birth is planned (induced labour or c-section) to save the life of mother or baby from pregnancy complications such as pre-eclampsia, fetal growth restriction, waters breaking early (PPROM) or infection
Preventing premature birth
Too often health professionals are not able to tell women why they have had a premature birth. This area of research is underfunded, with many taking an unhelpful (and unique to pregnancy) approach of ‘It was not meant to be’.
Research into why premature birth happens is the only way we can save lives and prevent future loss. Tommy's funds more than £400k of research into premature birth every year. We are focused on predicting early which women will have a premature birth and treating them to prevent it happening.
Join us for change
Together we can make a difference. We need everyone's help to change the statistics and find out why miscarriages happen. You can sign up today to support Tommy's work.
Media requests about premature birth
Our clinicians, scientists and researchers are available to speak about preterm birth for press and media. If you are interested in speaking to a clinician, contact Hannah Blake, telephone: 07730 039361 or email [email protected]
- WHO (2012) Country data and rankings for preterm birth 2012, World Health Organisation, Geneva, Switzerland, http://www.who.int/mediacentre/factsheets/fs363/en/
- ONS (2015) Pregnancy and ethnic factors influencing births and infant mortality: 2013, Office of National Statistics, London, England,
- WHO (2017) Preterm birth fact sheet 2017, World Health Organisation, Geneva, Switzerland, http://www.who.int/mediacentre/factsheets/fs363/en/
- Daniel F. MacKay, Gordon C. S. Smith, Richard Dobbie, Jill P. Pell (2010) Gestational age at delivery and special educational need: retrospective cohort study of 407, 503 schoolchildren 2010, http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.10...
- Wood NS, Marlow N et al (2000) N Engl J Med. Neurologic and developmental disability after extremely preterm birth. EPICure Study Group. 2000 Aug 10;343(6):378-84.
- Marlow N, Wolke D et al (2005) Neurologic and developmental disability at six years of age after extremely preterm birth. N Engl J Med. 2005 Jan 6;352(1):9-19.
This unique Preterm Surveillance Clinic – funded by Tommy's as part of our research in St Thomas' Hospital, London, has won an NHS Innovation Challenge Prize, for its success in reducing the number of premature births in South East London.
Tommy’s prematurity research centre in London is based at St Thomas’ Hospital, where the charity first began. Opened in 1995, it is the first Maternal and Fetal Research Unit in the UK.
If there is only one thing you take away from reading my story and Lukas’s, please take away 'hope'.
We've kept the eye mask he wore, to remind us of everything he made it through.
"I hope our story gives couples some reassurance that there is light at the end of the tunnel because after 9 miscarriages we have our miracle on the way"
Born weighing less than a bag of sugar over twenty-one years ago, Harriet has come a long way to today, in her final year of University, writing her dissertation on premature infants.