Updated February 2014

Premature birth statistics

Definitions

The World Health Organisation gives the following definitions for the different stages of preterm birth [1].

  • extremely preterm: less than 28 weeks
  • very preterm: 28 to 32 weeks
  • moderate to late preterm 32 to 37 weeks.

Incidence in the UK

  • England and Wales: in 2011, 7.2 percent of births are pre-term (under 37 weeks gestation). Of these, 1.3 percent will be born before 24 weeks [2]. The majority (95 percent) occurr after 28 weeks.
  • Nearly 5 percent of all babies born prematurely will have a very low birth weight (less than 1000g), compared to 93.7 percent of babies born under 24 weeks. Fewer than 1 percent of babies born at full term will be of very low birthweight [2].
  • Pre-term birth rates in England and Wales has remained steady (7.3 percent in 2009, 7.1 percent in 2010, 7.2 percent in 2011). Very early pre-term births (under 24 weeks) has also remined steady (1.3 percent in 2009, 1.5 percent in 2010, 1.3 percent in 2011). However, mortality rate of all pre-term births has dropped by 11 percent since 2006 [1].
  • In England and Wales, 9.5 percent of premature births are to mothers aged 40 and over, compared to 6.9 percent in mothers aged 20-24 [2]. 6.2 percent of babies born to mothers aged 40 years or over were multiples compared with just 1.2 percent of babies born to mothers in their teens. For mothers of all ages the percentage of multiple births was 3.2 percent.
  • Mortality rate of singleton pre-term babies is 25.8 in 1,000 live births compared to 23.9 in 1,000 live births in multiple pre-term babies [2].
  • Scotland: the percentage of pre-term (born before 37 completed weeks) singleton babies rose from 5.2 percent in 1975/76 to a peak of 6.7 percent in 2003/04 and has now fallen to 5.9 percent in 2011/12 [3]. Very low birthweight (less than 1500g) occurrs in 15.3 percent of premature babies. This has remained unchanged since 1976 (also at 15.3 percent) [3].
  • Northern Ireland does not currently compile figures on premature births.

Global incidence 

  • Globally, 15 million babies are born prematurely every year. This is equivalent to 1 in 10 births [1]. The rate of pre-terms births has increased over the last 20 years. It is thought this this is because of increased maternal age, increased rate in pregnancy-related complications such as gestational diabetes, greater use of infertility treatments leading to more multiple pregnancies, and more caesarean deliveries taking place before term [1].

Causes

  • 25 percent of pre-term births are planned caesarean sections because the mother might have severe pre-eclampsia, kidney disease, or because the baby is not developing properly [4].
  • 20 percent of cases are due to premature rupture of the membranes [5].
  • 25 percent of the cases will be due to an emergency event, for example placenta abruption (when the placenta detaches itself from the uterus), infection, eclampsia, or prolapsed cord (when the umbilicard cord exits the body before the baby) [5].
  • In 40 percent of the premature births the cause is not known [5].

Read more about the causes of premature birth here.

Survival

  • In England, survival rates of very premature babies have increased from 40 percent in 1995 to 53 percent in 2006, an increase in 13 percent [6].
  • Survival increases by 9.5 percent for each week if the baby is born at 24 weeks, and 16 percent per week  if the baby is born at 25 weeks [6].
  • Survival rates for the rest of the UK countries are not available.

Risk factors

  • Having more than two preterm deliveries increases the risk of another premature baby by 70 percent [5].
  • An abnormally shaped uterus increases the risk of giving birth early by 19 percent [5].
  • Women are nine times more likely to give birth early if they have a multiple pregnancy (twins, triplets) [5].

Health outcomes

More babies survive premature birth, but serious health problems remains unchanged [6]. Between 1995 and 2006 survival shortly after birth of very premature babies has increased by 13 percent (from 40 percent in 1995 to 53 percent in 2006), but the proportion of survivors leaving hospital with major health problems is unchanged [6]. Preterm birth is associated with [4]:

  • Respiratory complications and lung disease
  • Problems with bowel function
  • Long-term neurological damage

Read about your premature baby's time in hospital here

Long-term outcomes

A study following the progress of very premature babies (born before 27 weeks) in England has found a high level of disability once the children reached 6 years of age [6]:

  • 22 percent had severe disability (defined as cerebral palsy but not walking, low cognitive scores, blindness, profound hearing loss)
  • 24 percent had moderate disability (defined as cerebral palsy but walking, IQ/cognitive scores in the special needs range, a lesser degree of visual or hearing impairment)
  • 34 percent had mild disability (defined as low IQ/cognitive score, squint or refractive error, requiring glasses)
  • 20 percent had no problems.

When children born before 26 weeks were re-assessed in middle childhood (aged 11 years), they found that 45 percent had serious cognitive impairment. The following academic attainment was found [6]:

  • They had significantly lower scores for cognitive ability, reading and mathematics
  • 13 percent attended special schools.
  • 57 percent of those in mainstream schools had special educational needs (SEN).
  • Those who entered school an academic year early due to preterm birth had similar academic attainment but required more special needs support

Visit our section on premature birth



Sources

[1] World Health Organisation, Preterm birth, fact sheet No 363, Geneva WHO, 2013. Also available at: http://www.who.int/mediacentre/factsheets/fs363/en/ (accessed 11 February 2014)

[2] Office for National Statistics, gestation-Specific Infant Mortality in England and Wales 2011. Cardiff ONS, 2013. Also available at: http://www.ons.gov.uk/ons/publications/re-reference-tables.html?edition=tcm%3A77-320891 (accessed 11 February 2014)

[3] Information Services Division, Births in Scottish hospitals 2012, Edinburgh National Services Scotland, 2013. Also available at: http://www.isdscotland.org/Health-Topics/Maternity-and-Births/Publications/2013-08-27/2013-08-27-Births-Report.pdf?34511965514 (accessed 11 February 2014)

[4] National Institute for Health and Care Statistics, Preterm labour and birth, guidance scope (final), London NICE, 2013.

[5] Henderson C, Macdonald S, Mayes midwifery, a textbook for midwives. Philadelphia Balliere Tindall, 2011

[6] Costeloe K et al, Short-term outcomes after extreme pre-term birth in England, Comparison of two birth cohorts in 1995 and 2006 (the EPICure studies. BMJ 2012; 345:e7976

 


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Employment
Lifestyle statistics

Miscarriage statistics

Pre-eclampsia statistics

Premature birth statistics

Stillbirth statistics

Toxoplasmosis statistics


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Definitions

Incidence

Causes

Survival rates

Outcomes



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