Health conditions of preterm babies

What is Apnoea?

Before birth the foetus has an irregular breathing rhythm with frequent pauses, called periodic breathing. After birth this has to become regular. The breathing control systems need some time to adapt and periodic breathing is frequently seen in the more immature babies.

If the pause in breathing lasts for longer than 20 seconds, or if this period is accompanied by a slowing of the heart rate (the medical word for this is bradycardia) or by decreasing oxygen levels (measured as oxygen saturation), professionals call it apnoea.Breathing control becomes regular over the preterm period and most babies grow out of apnoea in the preterm period.

Who is affected and what are the risk factors?

Apnoea is fairly common health problem in preterm babies, as the central nervous system that controls breathing is not yet mature enough to allow regular breathing: Approximately 70% of preterm babies born before 34 weeks of gestation have apnoeas to some degree. The earlier a baby is born, the higher is the risk of developing apnoea.

What is the cause?

Although most apnoea result from periodic breathing, this may be made worse in the presence of lung disease or infection. Also in situations where adults breath faster (for example during illness or painful procedures) the baby responds with periodic breathing. Therefore, the doctor may want to perform some tests and offer treatment if apnoea increases in frequency or is troublesome.

How is it diagnosed?

By monitoring breathing, heart rate and oxygen saturation the healthcare team in the neonatal intensive care unit (NICU) can easily detect apnoea. If apnoea shows an unexpected course or if it lasts for a long time, the medical team may arrange different diagnostic tests, e.g. blood or urine tests or ultrasound, to find out if apnoea appears to be a symptom of some other condition.

How is it managed?

Babies in the NICU are constantly monitored. If an apnoea occurs, the healthcare team can immediately react to it. A small amount of physical stimulation (for example by gently touching the baby’s back or feet) can help the baby to begin regular breathing again. Sometimes, preterm babies may receive medication (usually caffeine medicine) to reduce apnoeic episodes. In some cases oxygen or respiratory support may be required.

What is Asphyxia and when does it occur?

Asphyxia is said to occur when the oxygen supply to the baby (or part of the baby’s body) is reduced to critical levels. It follows the effect of two events: where oxygen levels fall to very low levels (termed hypoxia) or where blood supply is interrupted (termed ischaemia).

If asphyxia persists, then it can cause damage to critical organs. Asphyxia can occur before birth, during birth, or (less commonly) due to major complications after birth leading to sudden collapse.

Who is affected and what are the risk factors?

Asphyxia at birth occurs in 1-2 per thousand births at full term, leading to a brain condition called encephalopathy (or hypoxic-ischaemic encephalopathy or HIE). It may be slightly more common during preterm birth but preterm babies often tolerate low oxygen levels somewhat better than babies born at or near term, and signs that the baby has been affected may be less common.

Asphyxia at birth is more common with maternal complications such as diabetes or hypertension.

What is the cause?

While in the womb, the baby receives oxygen from the mother’s blood through the placenta and the umbilical cord.

Asphyxia can occur when this oxygen transfer is disrupted, for example because

• the umbilical cord becomes blocked or stretched,
• the blood flow is reduced because of  low maternal blood pressure.
• the placenta separates from the womb early (called placental abruption).

These serious complications are difficult to identify early or to stop.
After birth, if breathing or circulation are disturbed for long periods because of severe illness such as infection, similar events can occur.

How is it diagnosed?

Before birth, fetal monitoring of the heart rate is used to give early warning of asphyxia. The lack of oxygen can also be detected through blood tests: a blood sample showing too much acid in the blood can indicate impending problems leading to early delivery. Samples of blood are frequently taken from the umbilical cord blood vessels at birth as a measure of what has happened.

After birth, babies who are suspected of asphyxia are examined carefully for signs of brain function, checking for the presence of altered function, which can be scored or graded to indicate severity. In addition, the electroencephalogram (EEG) is often used to check on the level of brain electrical activity, or ultrasound is used to identify any major problems. Later on, the healthcare team may suggest a magnetic resonance scan (MRI) to determine if there is evidence of brain injury.Other organ systems may also be affected by asphyxia, but tend to recover usually without problems – The healthcare team will explain if any tests are needed to show this.

How is it managed?

The major treatment strategy is to ensure that oxygen is delivered to all tissues in the body by increasing the level of oxygen the child breathes, or by ensuring that the blood pressure is maintained. Sometimes, extra drugs are needed to do this.

For babies who are delivered after 35 weeks, sometimes cooling the baby’s body temperature to 33 degrees (normal is 37 degrees) is used to prevent ongoing brain injury. A transfer to a specialist centre may be needed for this to be carried out.

What is bronchopulmonary dysplasia (BPD)?

Bronchopulmonary dysplasia (BPD) or chronic lung disease (CLD) is the term given to persisting lung symptoms that develop in a proportion of usually very preterm born babies (< 32 weeks), who are treated with oxygen and mechanical ventilation.

Early delivery may slow down lung development and injury to the fragile air sacs (alveoli) through which oxygen gets in to the body and waste gases (carbon dioxide) are removed. BPD causes symptoms, such as rapid breathing (tachypnoea), rapid heart rate (tachycardia), increased respiratory effort, and decreased oxygen levels, often treated by giving extra oxygen.

Who is affected and what are the risk factors?

BPD usually occurs in the most immature babies, in whom it is not uncommon, and much less frequently in more mature babies who have more severe lung problems.

Within this group, major risk factors are the need for help with breathing and the presence of infection around the time of delivery.

What is the cause?

The causes of this condition are very complex. Early delivery may slow down lung development. Oxygen and ventilation are essential treatments but themselves also may cause injury to the fragile air sacs (alveoli) through which oxygen gets in to the body and waste gases (carbon dioxide) are removed. These may be worsened in the presence of infection.

How is it diagnosed?

There are no definite tests to make a formal diagnosis. BPD usually, but not always, follows on from an intital period of respiratory illness. The medical term for is respiratory distress syndrome or RDS. Professionals tend to agree that babies who still require extra oxygen or support for their breathing after one month have BPD, but this usually will settle down with few later problems.

If very preterm babies still need extra oxygen at the equivalent gestational age of 36 weeks (i.e. at 8 weeks of age if a baby is born at 28 weeks), they are considered to have moderate BPD or severe BPD if they need more than 30% oxygen or ongoing respiratory support. These groupings are helpful as they indicate how long respiratory support may be needed and point the liklehood of symptoms later in infancy and childhood.

How is it managed?

For most babies with BPD simple monitoring of oxygen levels and blood gas levels suffices, although not infrequently babies may need periods of extra support for short periods. Special attention is given to nutrition as we know this is important in recovery after BPD.

What is Hypoglycaemia?

Sugar (glucose) is an essential source of energy in the body. Blood sugar levels fall after birth and if allowed to fall too low may cause brain injury or other problems. Low blood sugar (called hypoglycaemia) is said to occur when blood glucose levels fall to lower than 30 mg/dL (Milligram per Deciliter) (1.65 mmol/L (milimoles per Liter)) in the first 24 hours after birth or less than 45 mg/dL (2.5 mmol/L) thereafter. Mild hypoglycaemia can be asymptomatic in the first one or two days.

Who is affected and what are the risk factors?

Hypoglycaemia is one of the most common symptoms in newborn babies. Babies who are born preterm, small for gestational age, or following diabetes in the mother are at higher risk of developing this condition.

What is the cause?

Causes of hypoglycaemia include limited stores of glycogen (can be converted to glucose), and increased glucose need. This occurs in the three conditions above and also may occur with infection or if the baby’s body temperature drops. There are many other rarer causes of low blood sugar which the doctor will test for if the problem does not resolve quickly or there are no other risk factors.

How is it diagnosed?

Symptoms, which can be detected by the healthcare team include a low muscle tone (hypotonia), lethargy or apathy, poor feeding, blue or purple colour of the skin (cyanosis), apnoe, low body temperature (hypothermia), and seizure.

Usually, infants at risk for hypoglycemia are screened after birth by measuring blood sugar level.

A nurse, midwife or doctor takes a small blood sample from the heel of the baby, from the vein, or from an intravenous catheter that does not have glucose infusing in it. This sample can be analysed by either using a specific device to test blood sugar level (also called glucose meter) or lab analysis. Sometimes this screening is repeated in regular time intervals during the first hours or days, depending on the overall health condition of the baby.

How is it managed?

If hypoglycaemia persists despite oral feeding or is associated with severe symptoms, the medical team can give extra glucose orally or intravenously by giving a fluid containing glucose (usually, 5% or 10%) to stabilise the blood glucose level. The administration of glucose depends on the health situation of the baby.

What is an infection?

When organisms, such as bacteria, viruses, or fungi invade the body it is called infection. If the immunity of a baby is weakened, even an organism that occurs normally on the body can become infectious. An infection can affect some or all parts of the body, and can have varying degrees of severity. They can occur in lungs (pneumonia), blood (septicaemia), urinary tract, or in the fluid surrounding the spinal cord and the brain (meningitis).

What is neonatal sepsis?

Sepsis occurs when the body responds to an infection, usually septicaemia or blood stream infection. The symptoms are caused by chemicals or toxins from the infecting organism. This causes rapid generalised illness, shown as high body temperature, changes in blood pressure, or breathing difficulties.

Who is affected and what are the risk factors?

Preterm born babies are at higher risk for infections compared to term born babies. Infection can also affect the mother and be present at or soon after delivery. Generally the sicker the baby, the higher the risk of sepsis, and sepsis is particularly common when there are a lot of medical procedures (such as intravenous feeding lines).

What is the cause?

During the last three months of pregnancy (third trimester), so called antibodies actively cross through the placenta from the mother to the foetus. This helps protecting the newborn baby from infections. Depending on the time of birth, a baby may have missed out this important transfer of antibodies in the womb. In addition to a preterm baby’s still immature immune system, this makes the baby more vulnerable to infection.

In some cases, bacteria are transferred to the baby during pregnancy or the birth process (for example following premature rupture of the amniotic membranes). Infection can also be transferred during invasive medical procedures such as intravenous lines or breathing support by a mechanical ventilator. Some of these organisms rarely cause disease in older children or adults but cause the baby difficulties because of their immature immune system.

How is it diagnosed?

The medical team may consider an infection, when they recognise specific symptoms such as tiredness, fatigue, reduced responsiveness, fever, breathing difficulties, and reduced blood circulation. To diagnose an infection, blood or urine will be sampled for analysis. A lumbar puncture, also called spinal tap, may be performed to look for signs of an infection in the cerebrospinal fluid (meningitis). By analysing these body fluids the medical team can identify the specific organism causing the infection. This is required to provide the optimal treatment. Radiography of the chest may also help to detect infection of the lungs (pneumonia).

How is it managed?

If an infection is suspected in a preterm born baby, antibiotics which cover the most likely possible causes may already be given before the diagnosis of infection. In general, infections are treated with antibiotics, antiviral therapy, or antifungal therapy, depending on the infection-causing organism. Therapy will last for a couple of days or even weeks. Due to the infectious disease the baby may also need additional support , such as intravenous fluids, tube feeding, or breathing support.

What is intraventricular haemorrhage (IVH)?

Intraventricular haemorrhage (IVH) is bleeding into the deep spaces inside the brain called ventricles, where the cerebro-spinal fluid (CSF) is produced.The bleeding comes from a special tissue in the ventricles (called the germinal matrix), which normally disappears at around 34 weeks of gestation, so IVH is very rare after then.

The blood vessels in the germinal matrix are thin and vulnerable to instabilities in blood flow, which can cause them to rupture. This causes bleeding which may stay in the tissue or rupture out into the ventricular spaces, where it clots and can be seen using ultrasound

These clots can sometimes block the drainage of CSF (which flows through pathways from one ventricle to the next, then out across the outside of the brain and down the spinal cord), leading to a build up of the fluid under pressure. On other occasions, the clot can disturb the blood flow from the brain, leading to bleeding into the tissues around the ventricle. These two complications are now relatively rare and most very preterm babies do not develop IVH.

Who is affected and what are the risk factors?

IVH tends to occur in the most immature and smallest babies; it is also more common in babies who need help with their breathing in the first few days or have unstable blood pressure. IVH usually starts within the first two days following birth, but the effects may develop over the following days and weeks. What is the cause? Because of the very fragile blood vessels in the germainal matrix, IVH can be caused by changes of blood pressure or blood flow that occur during the birth process or as a result of many other conditions, such as breathing or blood pressure difficulties.

How is it diagnosed?

Most babies do not show any outward sign that an IVH has occurred and it is identified during routine screening using ultrasound which is carried out at the cotside, through the soft spot on their head (where the bones haven’t fused together yet) called the fontanelle. Other ways of imaging the body (such as Magnetic Resonance Imaging or MRI) are sometimes recommended but they are only used in specialist centres when the baby’s condition is stable. With more severe grades of IVH, signs and symptoms may sometimes be seen. Where flow of CSF is blocked, as the ventricles enlarge, swelling of fontanelle may be noticeable. Other symtoms can also include abnormally low blood pressure and heart rate, seizures, anaemia, apnoea, decreased muscle tone and reflexes. Other tests may be helpful in determining the effects of IVH such as EEG, video recording of the baby’s movements and tests of visual function.

How is it managed?

In general, the bleeding stops fairly quickly and the clots resolve as the body responds to them. Therefore, immediate treatment is not needed. The healthcare team keeps the baby stable and treats any symptoms.

If the flow of cerebrospinal fluid is interrupted due to the bleeding, and pressure increases within the ventricles, it may cause a condition called hydrocephalus.

This important condition can result in rapid head growth as the bones of the skull are not yet fused, as in older children. Several treatments are available including surgery for the placement of a “shunt”, which is a small tube that drains the fluid from the brain to another part of the body, usually the abdomen, and relieves the pressure.

What is Necrotizing Enterocolitis (NEC)?

Necrotizing Enterocolitis (NEC) is a serious illness characterised by inflammation and damage to the tissues of the intestine. In severe cases parts of the intestinal tissue may die.

Who is affected and what are the risk factors?

NEC is mainly a condition affecting preterm babies, usually after the second week following birth. The earlier the baby is born, the higher the risk of developing NEC. About 5 in 100 very preterm born babies develop this condition. Where babies are very ill or fed formula rather than human milk, the risk is highest.

Depsite the potentially severe illness, many babies with NEC will develop without serious complications later in life. However, although it is uncommon, NEC is one of the important causes of late death in preterm born infants.

What is the cause?

The causes of NEC are still not well understood. However three factors seem to come together in babies who develop NEC: low intestinal blood flow, presence of infection, and formula milk.

How is it diagnosed?

Sometimes it can be difficult to diagnose NEC because the symptoms, such as vomiting or abdominal distension, are found with many other feeding problems that are common in preterm born children.

Symptoms can also include an distended belly, diarrhoea, and blood in the stool (an important sign). The healthcare team will examine the abdomen regularly and use a stethoscope to listen to the bowel sounds. Infants who are developing NEC may appear to be very ill.

NEC has typical appearances on X-ray of the abdomen, although for some babies the diagnosis is only made at operation.

How is it managed?

When the healthcare team suspects NEC the first steps are to stop oral feeds, to start intravenous fluids (and nutrition) and to treat with antibiotics. The team will organise X-rays and blood tests. Often, this treatment is necessary for 7-10 days if the diagnosis is confirmed. For most babies with NEC this is all that is necessary.

Other babies are sicker and need support for their breathing and intensive care for several days.

Some babies may become profoundly ill with NEC and one of two surgical treatments may be used. The first is to insert a tube (called a ‘drain’) into the space outside the intestine to drain any fluid and relieve pressure on the bowel; this allows faster healing. The other option includes surgical removal of the affected part of the intestine, often followed at a later date by reattachment of the healthy bowel sections.

NEC can be a very serious condition and the healthcare team often start medical treatment first before the diagnosis is confirmed, only to confirm later that it was not actually NEC.

What is patent ductus arteriosus (PDA)?

In foetal life, a special blood vessel connects the circulation from the lungs to the arteries, supplying the rest of the body. This is called the arterial duct or ductus arteriosus. After birth, normally this vessel spontaneously closes and separates the two circulations. In very preterm babies the duct may not close immediately and for some it persists – for which the medical term used is patent ductus arteriosus (or PDA).

If the PDA is only partially open, there may not be any symptoms or consequences for the baby.

However, if the opening is larger, blood flow to the lungs can increase and the heart must pump more than usual to compensate this condition. This can occasionally lead to potential health problems such as respiratory complications, heart failure, or a reduced blood supply to the kidneys, the intestines, and the brain.

If left without treatment many PDAs eventually close but the healthcare team will weigh up the benefits and disadvantages of any health issues that may be made worse by the presence of a PDA.

Who is affected and what are the risk factors?

The earlier a preterm baby is born, the more likely it is to be affected by health issues resulting from PDA. For example, approximately four out of ten babies born before 34 weeks of gestation are estimated to develop a PDA.

What is the cause?

Foetal Circulation: While the foetus is in the womb, its oxygen needs are met by the mother. Oxygen from the mother passes through the placenta, along the umbilical vein and is pumped to the heart of the baby through a blood vessel called the ductus venosus. From there it is pumped to the rest of the body. The fetus does not need blood to pass through the lungs before birth, so it flows straight into the major artery (Aorta) through the ductus arteriosus. After blood has delivered the oxygen to the body of the foetus, the blood returns to the heart and is pumped back to the umbilical cord and placenta to be re-oxygenated.

In term-born babies, the ductus arteriosus closes rapidly after birth as it is no longer necessary. When breathing starts, blood flow through the ductus arteriosus falls off and increasing levels of oxygen encourage it to close. For some preterm babies, this closing process is delayed. If it remains widely open, then the heart must pump blood to both the lungs and the aorta at the same time leading to a range of health issues.

How is it diagnosed?

Most babies with a PDA have a heart murmur, which the the healthcare team will identify during their examination. Other symptoms include apnoea, abnormal blood pressure, changes in heart rate, and difficulties in breathing. Additionally, the oxygen saturation may decrease and carbon dioxide levels may increase in the blood, all of which are picked up using routine montoring in the NICU. Some times the heart size increases a little on X-ray. Using ultrasound, echocardiography can identify a PDA and monitor how well it responds to therapy.

How is it managed?

Sometimes PDA resolves without causing any serious problems, termed spontaneous closure. Often careful attention to fluid balance is all that is required.

Several drugs may be used to try to encourage a PDA to close, usually indometacin or ibuprofen, In some situations, surgery may be needed to close the PDA.

What is pneumothorax?

A pneumothorax is the accumulation of air in the cavity between the lungs and the chest wall (termed the pleural space), which can lead to a lung collapse.

Who is affected and what are the risk factors?

Babies with other lung diseases such as respiratory distress syndrome (RDS) or lung infection (pneumonia), babies on mechanical ventilators, preterm babies whose lung tissues are immature and vulnerable, and babies with meconium aspiration (when a newborn inhales/ aspirates a mixture of meconium and amniotic fluid) are most at risk to develop a pneumothorax. Pneumothorax may occur in about five to seven percent of babies with birth weight of less than 1,500 g.

What is the cause?

A pneumothorax occurs when tiny air sacs (alveoli) in the infant’s lung become overinflated and rupture. Air then tracks through the lung tissue and enters to pleural space. Normally there is no air in this space and its presence allows the lung itself to fall away from the chest wall and sometimes collapse. For some babies there is little sign this has occurred, while others can sudenly become very ill.

How is it diagnosed?

The medical team may be alerted by signs of a pneumothorax, such as a sudden decrease of the oxygen saturation in the blood or a drop in blood pressure or heart rate. A pneumothorax can in some cases be seen by shining a bright light through the tissue of the infant’s chest. Usually, a pneumothorax is diagnosed by chest X-ray.

How is it managed?

The size of the rupture mainly determines the treatment strategy for a pneumothorax. Sometimes, it is possible to remove the air with a needle and the rupture may close on its own. More often, a special tube called a ‘chest drain’ is inserted between the ribs to allow the continuous removal of the air. When the pneumothorax has resolved the drain can be removed safely.Additionally, it can be necessary to give supplemental oxygen to the baby and gently ventilate. Sometimes, high frequency oscillatory ventilation (HFOV) is used and antibiotics may be administered to reduce the risk of a lung infection.

What is pulmonary hypertension?

The blood pressure in the arteries that supply the lungs and the rest of the body are at similar pressure in foetal life. After birth, as the ductus arteriosus closes, after a short while the pressure in the lung circuit falls and for the rest of life this pulmonary circuit works at a lower pressure compared to the rest of the circulation (systemic circulation).

The pulmonary artery transfers blood from the right side of the heart to the lungs. In some situations the pulmonary pressure remains or becomes high, when it is termed pulmonary hypertension. This situation can lead to several health problems, depending on whether it occurs suddenly (acute) or persists over a much longer period (chronic).

Who is affected and what are the risk factors?

The disease is very rare in babies. About 1-2 of 1000 newborn babies may be affected, and it arises mainly during periods of intensive care. It sometimes accompanies asphyxia or bronac

What is the cause?

Pulmonary hypertension can occur as part of severe acute illness, such as during mechanical ventilation for a range of conditions, or be chronic due to the effect of severe lung disease or a PDA. Extremely rarely it occurs on its own, when it may be termed idiopathic pulmonary hypertension.

How is it diagnosed?

The main observation is a need for high oxygen concentrations in excess of what would be expected from any lung disease. Usually it is diagnosed following an ultrasound examination (echocardiography).

How is it managed?

Pulmonary hypertension may resolve with better ventilation, e.g. using high frequency oscillatory ventilation (HFOV). It also sometimes resolves with the use of inhaled nitric oxide gas. Very rarely in term babies, usually after aspiraton of meconium, it is reistant to ordinary treatment and babies may be referred for a complex treatment termed ECMO. The healthcare tea would discuss this in more detail if it is required and it is not used for small preterm babies.

What is respiratory distress syndrome (RDS)?

Babies born without enough surfactant (a substance which helps the air sacs in the lung remain open), develop a condition called respiratory distress syndrome (RDS), also known as hyaline membrane disease.

Who is affected and what are the risk factors?

RDS occurs almost exclusively in preterm born infants due to the immaturity of their lungs and an inability to make sufficient surfactant. Babies born at the lowest gestations are at greatest risk: RDS affects approximately half of infants born at 26-28 weeks of gestation and a  third of babies born at 30-31 weeks of gestation. Given antenatal steroid medication to mothers in the days before delivery reduces the risk and severity of RDS and is an important preventive treatment.

What is the cause?

Surfactant is secreted by the lining cells in the lung in small quantities from mid-gestation – 23-25 weeks. Surfactant synthesis is switched on by the processes that lead to birth (and by antenatal steroids) but may not be established until several days after birth.

Surfactant works in the airsacs (called alveoli), and its presence makes the lungs easier to inflate and less likely to deflate at the end of a breathing cycle. As babies work harder to open their lungs or in the presence of asphyxia or infection, more surfactant is used up, leading to the symptoms of RDS.

How is it diagnosed?

The healthcare team will look for symptoms such as rapid breathing, apnoea, and a characteristic grunt just as the baby breathes out. Blood tests and X-rays of the chest are used to confirm the diagnosis and help the team know the treatment is working.

How is it managed?

If preterm birth is not completely unexpected, the mother may be given steroids which cross the placenta and help the baby to produce surfactant in the lung.

The healthcare teams now prefer to prevent RDS if they can and so they often help babies breathing, for example with CPAP, before they develop symptoms. If it looks likely that the baby is developing RDS, the team can give artificial or natural surfactant, also called surfactant replacement therapy. There are several types of surfactant replacement therapy available. Some experts prefer to give surfactant replacement treatment into the lungs immediately after birth, while others give it when needed. The dose may need to be repeated.

Alongside surfactant, babies usually need extra help to stabilise breathing, e.g. by giving extra oxygen or some form of breathing support, such as CPAP or ventilation. Most affected preterm babies recover from RDS without severe complications over the course of the first week.

What is Retinopathy of Prematurity (ROP)?

Retinopathy of Prematurity (ROP) is a condition found in the eyes of ex-preterm babies. It is characterised by changes in the developing blood vessels of the retina (the light-sensitive layer in the back of the eye that sends visual signals to the brain).

Although mostly it resolves without problems, if not identified and treated,  progressive disease can lead to scarring and retinal detachment (separation of the retina from the inside of the eye), causing poor vision or even blindness.

Who is affected and what are the risk factors?

Many different factors contribute to the development of ROP. Babies born before 31 weeks or less than 1,250g birthweight are at highest risk. The main risk factor is the use of oxygen therapy. The healthcare teams monitor oxygen levels in the baby very closely and try to find a balance between enough oxygen to prevent other serious diseases and too much, which encourages ROP.

The occurrence of the disease varies across countries, regions and facilities and is determined by the quality of neonatal care and the resources of the facility. For example, among babies born in Western countries after 30-32 weeks of gestation, two to nine percent of the babies may develop some grade of ROP. When born at 26 weeks of gestation, the number increases to 50 percent. Those babies born below 26 weeks are at highest risk and the progression of ROP may be particularly rapid in this group.

What is the cause?

After birth (usually before 30 weeks of pregnancy) the blood vessels stop their normal growth out from the back of the eye, that starts as early as 16 weeks of pregnancy and usually covers the whole retina by 40 weeks of pregnancy (full term).

This leads to poor delivery of oxygen and nutrients to the developing tissue. As the eye recovers from this (usually after 31 weeks of gestation), the new blood vessels may grow in an abnormal manner that can cause major problems.

How is it diagnosed?

All preterm babies born before around 31 weeks of pregnancy or having a birth weight less than 1,250g to 1,500g may have eye examinations to detect the presence of ROP by a specialised eye doctor, called ophthalmologist. Since there is a lag period after birth until an ROP develops, the first screening usually takes place after four to six weeks following birth. It continues until the ophthalmologist is happy that the vessels have fully grown in the outer parts of the eye and any ROP has resolved.

Before screening, the baby receives eye drops to dilate the pupils so the retina can be seen fully. During the examination the child is usually wrapped and held by a parent or nurse to comfort and avoid movement. The procedure is uncomfortable for the babies and they may cry during the examination. Parents may wish to comfort their baby afterwards. Increasingly, the doctors and nurses on the neonatal unit may take photographs of the retina for the ophthalmologist to evaluate the status of the eye and to document how the vessels develop.

How is it managed?

Although most babies do not need treatment, it is very difficult to predict in which babies ROP will disappear and which will develop more severe disease.
This is why it is very important that an ophthalmologist continues with the screening in regular time intervals until the vessels cover the retina or the condition is considered stable. Sometimes, examinations have to continue until a few months after discharge.

If the progression of ROP reaches certain stages, treatment is warranted. There are different treatment options, of which usually one is applied depending on the stage and zone at time of treatment:

• Laser therapy works by destroying the peripheral areas of the retina causing abnormal vessels to disappear. Unfortunately, the treatment also affects later side vision. The treatment works usually very quick after treatment, and eyes are examined again five to seven days after treatment.
• A newer type of therapy is the injection of an antibody that binds a growth factor (VEGF) that makes the blood vessel grow disorganised, as it is the case in ROP. The same treatment is widely used in adults with conditions, where the same growth factor is causing eye problems. In babies, there were only a few studies with small case numbers. Therefore the long-term safety and efficacy of this therapy still needs to be proven.
• Cryotherapy  (applying a freezing probe to the outside of the eye to stop vessel re-growth) was the first treatment for ROP but is more difficult to use in very small babies and is nowadays used less frequently.

Respiratory Syncytial Virus or RSV is a respiratory virus that infects the lungs and breathing passages. It is widely spread and especially common during the cold autumn, winter and spring months. Everyone is at risk of contracting RSV which affects almost every child and most will have been infected with the virus by the age of two.

The majority of healthy people will experience flu-like symptoms while people with a weak immune system, for example the elderly and very young children, have a high risk of severe infection from RSV.

People ill with chronic lung diseases, preterm infants, children with compromised immune systems, children with heart disease or children with Down Syndrome have also much higher rates of severe RSV infections. The same goes for those with neuromuscular diseases. Chronic disease per se is an important risk factor for RSV hospitalisation and makes a severe infection more likely.

We have summarised the most important information about RSV in a comprehensive factsheet that can be downloaded here.

What makes RSV dangerous?
RSV is the primary cause of bronchiolitis which is an inflammation of the bronchial tubes (small airways in the lungs) and lungs. Bronchiolitis (not to be confused with bronchitis) is the most common infection of the lower airways in infants. The majority of bronchiolitis hospital admissions have been caused by RSV.
RSV is also a common cause of pneumonia, which is a lower respiratory tract infection.

It causes the air sacs of the lungs (the alveoli) and the smaller bronchial tubes to become inflamed and fill with fluid. An affected child might be unable to breath and will not get enough air.
Unfortunately there is no treatment for an acute RSV infection available that can combat the cause of the disease. Only the symptoms can be treated.

What factors increase the risk of RSV?
Children are at higher risk if they attend childcare centres or if their older siblings attend school, hence by being more exposed to RSV through contact. A family history of asthma also increases the risk of a more severe infection. The same goes for being exposed to tobacco smoke and other air pollution. Multiple birth siblings are also at higher risk as they are often born preterm and with a low birth weight. Moreover, they tend to (re)infect each other and are therefore more at risk to catch the virus.

Outbreaks of RSV infection occur on a yearly basis, usually during the colder months of a year. Epidemics of RSV typically last approximately five months (from October to April in the northern parts of the globe and from July to September in the southern parts of the globe).However, in recent years RSV-season has been started in September already in Western and Central Europe. Often, the season finds its peak in January and February, less often in November and December.

Why are preterm infants more likely to get infected by RSV?
Whilst full-term infants receive antibodies through their mother during the pregnancy, preterm infants did not get enough maternal antibodies over the placenta. Therefore, preterm infants are more likely to contract the RSV in the first few weeks of their life and onwards.

Furthermore, preterm infants are often artificially respirated which might damage their lung tissue leading to the chronic lung disease BPD (bronchopulmonary dysplasia). These children are therefore more likely to contracting RSV as well as to go through a more severe acute infection because their bodies already limit their oxygen supply.

What are the symptoms of RSV?
In the beginning, the initial symptoms of bronchiolitis often resemble the common cold.

Symptoms can be:

• a runny or blocked nose
• an increased body temperature
• a decrease in appetite
• a dry, “croupy” cough (often described as a “seal bark” cough)
• breathing difficulties

Further symptoms of RSV might include:

• persistent coughing and wheezing
• high fever
• sudden gasping for breath

Pneumonia caused by RSV has flu-like symptoms but can also include:

• coughing with mucus (possibly green, rusty or blood stained)
• shortness of breath
• chest pain

Should a newborn and especially a child at risk or with chronic disease show any of these symptoms, it is important to contact a healthcare professional immediately.

How is RSV transmitted?
The virus is spread by infected people sneezing or coughing whilst releasing droplets containing the virus into the air, which are then breathed in or come in contact with the mouth, nose or eye(s) of someone else. Infection can even occur when one touches their mouth, nose, or eyes after touching a contaminated object or surface. The RSV spreads rapidly and can live for half an hour or more on hands, up to five hours on objects and worktop surfaces and for several hours on used tissues.

The incubation period of RSV is between 2 – 8 days, on average it is 5 days. Some people infected with RSV show the first symptoms one day after having contracted the virus. Generally most people with a strong immune system are contagiousness for 3 – 8 days. However, preterm infants, infants and patients with immune deficiencies can be infectious for several weeks, rarely even for months according to the Robert Koch Institut.

How can the RSV risk be lowered?
There is no RSV vaccine but preventive therapy has proved an important strategy to manage the virus. Parents of preterm infants and children at risk should consult with a health professional for more information. For example, children at particular risk can be supported in their defense against RSV using a special protective approach known as passive immunisation.

To reduce the risk of infection with RSV, the following preventive steps should also be adapted:

• Covering of the nose and mouth with a tissue when coughing or sneezing
• Disposal of used tissues in the bin after use
• Washing of hands often and use soap and warm water (or an alcohol-based cleaner if soap and water is not available; anti-bacterial cleaners do not kill viruses)
• Touching of preterm infants and newborns only after hands have been washed
• Avoiding of touching of eyes, nose and mouth as germs can spread in this way
• Limiting physical contact with anyone who has a cold, fever or runny nose
• Disinfecting toys, play areas and surfaces (such as table tops) as germs can live for over 24 hours on household items
• No smoking nearby the baby and changing of clothes which were exposed to smoke (even second-hand smoke) before picking up the child
• Trying to avoid places where there are lots of people (e.g. public transport, big shopping malls and waiting rooms)

What are the short- and long-term effects of a RSV infection?
In the short term a RSV infection might lead to either a cold or flu. The more severe cases will result in sometimes life-threatening bronchiolitis, pneumonia, BPD (bronchopulmonary dysplasia) or even death (1 in 100) due to limited lung function.
Some children who have suffered a severe RSV infection may develop childhood asthma or show symptoms very similar to those of asthma.

As a result, they may suffer from the consequences of an RSV infection for an extended period of time.
A child who once contracted RSV does not develop immunity from future RSV infections. It is possible to experience repeated episodes of RSV infection.

What else can be done to improve health of children at risk in regards to RSV?
Always monitor your child closely for infections because an early identified infection is easier to manage.

For more information please download our Factsheet RSV  and our newly updated Position paper.

Please also visit our special RSV project pages Little Lungs – RSV in preterm and high risk infants and Are you RSV aware? for further information about the RS virus.