In recent years, the number of children surviving premature birth has grown. This means that there is potential to be an increase in the number of children and adults in the future with lung problems due to prematurity. This factsheet looks at how preterm birth affects the lungs, what can be done to reduce the impact of problems associated with preterm birth, both as an infant and later in life, and advice for parents of prematurely born babies.

What is preterm birth?

The average pregnancy lasts for approximately 37-42 weeks. When a baby is born before the completed 37 weeks of pregnancy, it is considered preterm. Those born before the 28th week of pregnancy are considered extremely preterm.

75% of preterm births are born after 32 weeks, although the babies with the most severe health problems are seen within the ‘extremely preterm’ category. Nearly 15 million babies worldwide and about 500,000 babies in Europe are born preterm each year, one in ten. In the light of these numbers, preterm infants represent Europe’s largest child patient group and preterm birth has become the major cause of infant death and disabilities from birth in both developed and developing countries.

How is preterm birth linked to lung disease?

The lungs are one of the last organs to develop as a baby is growing inside the womb. This means that when a baby is born prematurely his/her lungs are not fully developed which may lead to both short and long-term ‘health problems’.

Respiratory distress syndrome (RDS)

RDS is one of the leading causes of death in babies born prematurely. It occurs in babies whose lungs are not fully developed and is mainly caused by a lack of a protective substance called surfactant. This substance helps to keep a baby’s lungs inflated with air and when babies suffer a shortage of it, they need to be given oxygen through a tube and a substitute for surfactant. RDS can lead to a higher risk of developing BPD and severe respiratory infections in the first two years of life and an increased likelihood of asthma later in life.

Bronchopulmonary Dysplasia (BPD)

The most common lung disease affecting preterm babies is a condition known as Bronchopulmonary Dysplasia (BPD). It is characterised by rapid breathing, shortness of breath and gasping and coughing to get more oxygen. The condition usually develops as a consequence of preterm babies being given mechanical ventilation. This is when ventilators breathe for the baby until the lungs can do it themselves. Although this process is often essential to the survival of the baby it can damage the baby’s lungs, causing inflammation leading to the development of BPD. BPD can be a temporary condition, but for some children, symptoms can persist into adulthood, increasing the risk of developing chronic lung disease such as chronic obstructive pulmonary disease (COPD).

Respiratory syncytial virus (RSV)

Nearly all babies will contract RSV by the time they are the age of two. For most babies who are born at full term, the symptoms of the virus are similar to a common cold. Full-term babies get antibodies from their mothers during pregnancy which help to fight RSV and other viruses. However, when a baby is born even only a few weeks early, they do not get enough of these antibodies before birth. This lack of antibodies, combined with the fact that the lungs are not yet fully developed, means that prematurity is the greatest risk factor for severe RSV infection. The symptoms of the virus may include persistent coughing and wheezing, high fever and sudden gasping for breath. If your baby is showing these symptoms, it is important you contact your doctor as soon as possible. Parents can help prevent their babies contracting the infection by prophylaxing their preterm baby against RSV and encouraging those in close contact with the baby to regularly wash their hands, especially before touching the baby, and by cleaning toys, bedding and play areas frequently. They should also prevent anyone smoking near their baby.