Every year, an estimated 15 million babies are born preterm (before 37 completed weeks of gestation), and this number is rising.
Preterm birth complications are the leading cause of death among children under 5 years of age, responsible for nearly 1 million deaths in 2015.
Three-quarters of them could be saved with current, cost-effective interventions.
Across 184 countries, the rate of preterm birth ranges from 5% to 18% of babies born.
Preterm is defined as babies born alive before 37 weeks of pregnancy are completed. There are sub-categories of preterm birth, based on gestational age:
extremely preterm (<28 weeks)
very preterm (28 to <32 weeks)
moderate to late preterm (32 to <37 weeks).
Induction or caesarean birth should not be planned before 39 completed weeks unless medically indicated.
An estimated 15 million babies are born too early every year. That is more than 1 in 10 babies. Almost 1 million children die each year due to complications of preterm birth. Many survivors face a lifetime of disability, including learning disabilities and visual and hearing problems.
Globally, prematurity is the leading cause of death in children under the age of 5. And in almost all countries with reliable data, preterm birth rates are increasing.
Inequalities in survival rates around the world are stark. In low-income settings, half of the babies born at or below 32 weeks (2 months early) die due to a lack of feasible, cost-effective care, such as warmth, breastfeeding support, and basic care for infections and breathing difficulties. In high-income countries, almost all of these babies survive.
More than three-quarters of premature babies can be saved with feasible, cost-effective care, e.g. essential care during child birth and in the postnatal period for every mother and baby, provision of antenatal steroid injections (given to pregnant women at risk of preterm labour and under set criteria to strengthen the babies’ lungs), kangaroo mother care (the baby is carried by the mother with skin-to-skin contact and frequent breastfeeding) and antibiotics to treat newborn infections. For example, continuity of midwifery-led care in settings where there are effective midwifery services has been shown to reduce prematurity by around 24%.
Preventing deaths and complications from preterm birth starts with a healthy pregnancy. Quality care before, between and during pregnancies will ensure all women have a positive pregnancy experience. WHO’s antenatal care guidelines include key interventions to help prevent preterm birth, such as counselling on healthy diet and optimal nutrition, and tobacco and substance use; fetal measurements including use of ultrasound to help determine gestational age and detect multiple pregnancies; and a minimum of 8 contacts with health professionals throughout pregnancy to identify and manage other risk factors, such as infections. Better access to contraceptives and increased empowerment could also help reduce preterm births.
Why does preterm birth happen?
Preterm birth occurs for a variety of reasons. Most preterm births happen spontaneously, but some are due to early induction of labour or caesarean birth, whether for medical or non-medical reasons.
Common causes of preterm birth include multiple pregnancies, infections and chronic conditions such as diabetes and high blood pressure; however, often no cause is identified. There could also be a genetic influence. Better understanding of the causes and mechanisms will advance the development of solutions to prevent preterm birth.
Where and when does preterm birth happen?
More than 60% of preterm births occur in Africa and South Asia, but preterm birth is truly a global problem. In the lower-income countries, on average, 12% of babies are born too early compared with 9% in higher-income countries. Within countries, poorer families are at higher risk.
The 10 countries with the greatest number of preterm births1:
India: 3 519 100
China: 1 172 300
Nigeria: 773 600
Pakistan: 748 100
Indonesia: 675 700
The United States of America: 517 400
Bangladesh: 424 100
The Philippines: 348 900
The Democratic Republic of the Congo: 341 400
Brazil: 279 300
The 10 countries with the highest rates of preterm birth per 100 live births:
Malawi: 18.1 per 100
Equatorial Guinea: 16.5
Of 65 countries with reliable trend data, all but 3 show an increase in preterm birth rates over the past 20 years. Possible reasons for this include better measurement, increases in maternal age and underlying maternal health problems such as diabetes and high blood pressure, greater use of infertility treatments leading to increased rates of multiple pregnancies, and changes in obstetric practices such as more caesarean births before term.
There is a dramatic difference in survival of premature babies depending on where they are born. For example, more than 90% of extremely preterm babies (<28 weeks) born in low-income countries die within the first few days of life; yet less than 10% of babies of this gestation die in high-income settings.
In 2012, WHO and partners published a report “Born too soon: the global action report on preterm birth” that included the first-ever estimates of preterm birth by country.
WHO is committed to reducing the health problems and lives lost as a result of preterm birth with the following specific actions:
working with Member States and partners to implement "Every Newborn: An Action Plan to End Preventable Deaths" adopted in May 2014 in the framework of the UN Secretary-General’s "Global Strategy for Women’s and Children’s Health";
working with Member States to strengthen the availability and quality of data on preterm births;
providing updated analyses of global preterm birth levels and trends every 3 to 5 years;
working with partners around the world to conduct research into the causes of preterm birth, and test effectiveness and delivery approaches for interventions to prevent preterm birth and treat babies that are born preterm;
regularly updating clinical guidelines for the management of pregnancy and mothers with preterm labour or at risk of preterm birth, and those on the care of preterm babies, including kangaroo mother care, feeding babies with low birth weight, treating infections and respiratory problems, and home-based follow-up care (see WHO 2015 recommendationson interventions to improve preterm outcomes);
developing tools to improve health workers’ skills and assess the quality of care provided to preterm babies; and
supporting countries to implement WHO's antenatal care guidelines, aimed at reducing the risk of negative pregnancy outcomes, including preterm births, and ensuring a positive pregnancy experience for all women.
Guidelines to improve preterm birth outcomes
WHO has developed new guidelines with recommendations for improving outcomes of preterm births. This set of key interventions can improve the chances of survival and health outcomes for preterm infants. The guidelines include interventions provided to the mother – for example steroid injections before birth, antibiotics when her water breaks before the onset of labour, and magnesium sulfate to prevent future neurological impairment of the child. As well as interventions for the newborn baby – for example thermal care (e.g. kangaroo mother care when babies are stable) , safe oxygen use, and other treatments to help babies breathe more easily.
WHO recommendations on interventions to improve preterm birth outcomes
1 Blencowe H, Cousens S, Oestergaard M, Chou D, Moller AB, Narwal R, Adler A, Garcia CV, Rohde S, Say L, Lawn JE. National, regional and worldwide estimates of preterm birth. The Lancet, June 2012. 9;379(9832):2162-72. Estimates from 2010.