Chronic neonatal lung disease factsheet


Chronic neonatal lung disease (CNLD), is a condition where newborn babies have trouble breathing for a longer period than usual. It is also known as bronchopulmonary dysplasia (BPD)

CNLD can happen when the lungs are weak, not fully developed, or get damaged during birth. 

CNLD is common in premature babies, born before 36 weeks of pregnancy. This is because their lungs are not ready yet and can be easily damaged.

Other causes of CNLD after birth can include:

  • oxygen use - large amounts of oxygen can damage the cells of the lungs
  • mechanical ventilation - the air pressure from breathing machines
  • infection in the lungs like pneumonia
  • weakness in the chest wall or muscle
  • aspiration – when the airways are damaged after breathing in body fluids like saliva, breast milk or formula.

Babies have a higher risk of CNLD if they:

  • are born prematurely – before 36 weeks of pregnancy
  • weight less than 1500 grams at birth
  • have patent ductus arteriosus (PDA) – where a connection between the blood vessels of the heart and lungs does not close as it should 
  • have pulmonary hypoplasia – small or underdeveloped lungs
  • are male.

Some pregnancy conditions can also increase the risk of CNLD, including:

  • chorioamnionitis – an infection in the uterus that affects the placenta and fluid around the baby
  • gestational diabetes – a condition where hormones from the placenta stop blood sugar from being processed properly.

Babies with CNLD will usually stay in the neonatal intensive care unit (NICU) after they are born for management.

 Signs and symptoms

Babies with CNLD will have signs of respiratory distress when they are born. This means they are having trouble breathing.

Symptoms include:

  • fast breathing
  • flaring nostrils
  • grunting
  • sucking in the chest when they breathe.


CNLD is diagnosed when a baby has respiratory distress at birth that needs treatment and support for longer than normal.

Babies are checked after birth to make sure they have good:

  • heart rate
  • reflexes and responsiveness
  • muscle tone
  • breathing.

If a baby is having trouble or working too hard to breathe normally, they will go to the NICU for further checks and breathing support.

Babies who are born with severe respiratory distress may need scans of their lungs, like X-rays. This is to check the development and appearance of the lungs.


CNLD is treated with:

Premature babies may still need support through a breathing machine or oxygen after they reach an adjusted age of 36 weeks.

Treatment of CNLD depends on:

  • how premature your baby is
  • their general health
  • how severe the breathing difficulties are
  • other health conditions or complications 
  • how your baby is responding to treatment
  • how much oxygen your baby needs and how long they have needed it for,

CNLD can be a long-term condition. Some babies with CNLD will need extra oxygen support in the NICU or special care nursery for several months. 

Other babies may need to be on oxygen support at home after leaving the hospital. Babies who go home on oxygen will usually stop needing it by the time they are 12 months old. 


CNLD and future health

Babies with CNLD have a higher risk of severe respiratory infections from common childhood illnesses like: 

They may need to go back to the hospital for breathing support if they become sick. Speak to your local doctor if you are concerned.

Last updated Monday 29th April 2024


This factsheet is provided for general information only. It does not constitute health advice and should not be used to diagnose or treat any health condition.

Please consult with your doctor or other health professional to make sure this information is right for you and/or your child.

The Sydney Children’s Hospitals Network does not accept responsibility for inaccuracies or omissions, the interpretation of the information, or for success or appropriateness of any treatment described in the factsheet.

© Sydney Children’s Hospitals Network 2024