Having a premature baby opens up a whole new language, full of medical terms that seem designed to confuse the anxious parent. It will seem a bit overwhelming to start. But don’t worry, you will soon get to know and understand much of it.  If your baby's nurse or doctor uses a term that you don't understand, please ask to have it explained.

We have set out below some words, phrases and abbreviations used frequently with simple definitions. 


Substance that helps to break down food in the stomach.


Tiny sacs which make up the spongy tissue of lungs.


A condition in which the blood does not have enough red blood cells which, depending on the degree, can lead to hypoxia (lack of oxygen) in organs.


A substance or treatment which temporarily reduces or eliminates sensation (including pain).


Drugs used to relieve or eliminate pain. Aspirin is an analgesic.


Drugs used to treat infections by killing  bacteria or reducing their growth.


A drug used to stop or prevent seizures (fits/convulsions).

Apnoea or Apnea

A short period of time when a baby stops breathing. The baby may change colour and become blue-ish and become bradycardic and require stimulation to remember to breathe.

Apnoea alarm or mattress

A device that alarms if the baby's breathing stops for a certain period, typically about 20 seconds.

Appropriate Gestational Age (AGA)

Describes a foetus or baby whose size is within the normal range for his or her age or gestation.

Arterial Blood Gas Test (ABG)

An arterial blood gas test measures the acidity and levels of oxygen and carbon dioxide in the blood from an artery. The test looks at how well lungs work.

Arterial Septal Defect (ASD)

A hole in the wall between the two upper chambers of the heart.


Lack of sufficient oxygen to the tissues of the body.  Kidneys and brain are most sensitive to lack of oxygen.


Breathing-in a foreign material such as meconium, milk, stomach fluids.

Autism Spectrum Disorder (ASD)

A condition that affects how someone interact with people and the world around them.


Filling lungs with air and oxygen by squeezing a bag that is either connected to a facemask or an endotracheal tube allowing the baby to breathe. See endotracheal tube.


Damage to a baby's lungs caused by a ventilator


An antibiotic.


A fluid procued by the liver which is stored in the gallbladder and used in the digestion of fat


Special lights used to treat jaundice. 


A breakdown product of red blood cells, processed and excreted by the liver. If not processed quickly enough can lead to build up of bilirubin causing jaundice.

Birth Weight (BW)

Low Birth Weight baby (LBW): weighs less than 2,500 g (5.5 lbs)

Very Low Birth Weight baby (VLBW): weighs less than 1,500 g (3.0 lbs)

Extremely Low Birth Weight baby (ELBW): weighs less than 1,000 g (2.2 lbs)

Blood Gases

Blood taken from an umbilical arterial catheter or via a heel prick to measure the oxygen and carbon dioxide levels of the blood. See umbilical catheter.

Blood Glucose

The level of glucose (naturally occurring sugar) in the blood.

Blood Pressure (BP)

The pressure exerted by circulating blood upon the vessels of walls to blood vessels. One of the principal vital signs.

Blood Transfusion

The transfer of blood or blood components from a donor to another person via a vein.

Bradycardia (Brady)

An abnormally slow heart rate. When baby's heart rate drops below 100 beats per minute.


The large air tubes leading from the windpipe (trachea) to the lungs that convey air to and from the lungs.

Broncho Pulmonary Dysplasia (BPD)

Damage to lungs which sometimes occurs after ventilation or intensive oxygen therapy (see CLD)


A small plastic tube that is inserted into a blood vessel using a needle.

Carbon Dioxide (CO2)

The gas produced by the body during metabolism, which is removed by breathing out.

Cardiac Monitor

Machine used to measure the baby's heart rate, respirations, oxygen level in blood and blood pressure.

Cardiopulmonary Resuscitation (CPR)

Resuscitation to re-establish breathing and heart rate.

Cardiovascular system

The heart and blood vessels.

Central Line or Central Catheter

A thin tube placed in a vein or artery that takes medications, fluids and nutrients to the body through a large blood vessel (vena cava) that carries blood to the heart. Central lines also include umbilical venous and artery catheters. See umbilical venous and artery catheters.

Central Venous Line (CVL)

A soft, long plastic tube called a catheter that is placed in a vein.

Central Venous Pressure (CVP)

CVP measures the amount of blood returning to the heart and the ability of the heart to pump the blood into the arterial system.

Cerebral Palsy (CP)

Nervous system disorder, characterised by abnormal muscle tone (high tone) and movement.

Cerebral Spinal Fluid (CSF)

Fluid around the spinal cord and brain.

Chronic Lung Disease (CLD)

Long-term respiratory (breathing) problems and dependence on oxygen following a long period of ventilation. Also known asbronchopulmonary dysplasia (BPD)


Surgical removal of foreskin of penis.


High protein fluid which is produced by the breasts 3 or 4 days after delivery.

Complete Blood Count (CBC)

A count of the different types of cells present in blood. Red cells carry oxygen, white cells for fighting infection and platelets for prevention of bleeding.

Congenital Heart Disease (CHD)

An abnormality of the heart that occurs shortly after conception


Existing at time of birth

Continuous Positive Airway Pressure (CPAP)

A type of ventilation that delivers oxygen or air under pressure to baby through their nose though small tubes.

Cortical Visual Impairment (CVI)

A form of visual impairment that is caused by a brain problem rather than an eye problem.

CT Scan

A 3D X-ray often used to show size and position of many parts of brain. Can be used for other parts of body.


A laboratory test of urine, blood, spinal fluid etc to see identify if germs are present.


Blue colouring of the skin when there is not enough oxygen in the blood

Death - Neonatal

Death of a baby within 28 days of birth

Death - Perinatal

Stillbirth or death occurring within the first week of life

Developmental Dysplasia of the Hips (DDH)

Where the ball and socket of the hip do not develop properly.

Dextrose 5% in water (D5W)

A solution of a naturally occurring sugar in water given intravenously.

Dextrose 10% in water (D10W)

A solution of a naturally occurring sugar in water given intravenously.


Identification of the disease or problem.


Large muscle that separates the chest (thoracic) cavity from the abdomen. The diaphragm is the main muscle of respiration.


Substance or drug which increases the amount of urine produced. 

Do Not Resuscitate (DNR)

A medical order not to resuscitate or revive a terminally ill baby.

Echocardiogram (Echo)

Test to look at the heart using sound waves through the chest a bit like ultrasound during pregnancy.


Puffy skin caused by fluid building up in body tissues.

Electrocardiogram (ECG)

Machine that measures electrical activity of the heart (also known as EKG)

Electro-Encephalogram (EEG or EKG)

Machine that measures electrical activity in the brain.


Chemicals in the blood, such as potassium, calcium and sodium, which help control the flow of water across cell membranes.


Inflammation of the brain.


Inflammation of the lining of the heart or heart valves


In the windpipe (tracheal).

Endotracheal Tube (ETT)

A tube placed through either the baby's mouth or nose into the trachea (windpipe).


Chemical produced by the body which helps to break down and digest food.

Exchange Transfusion

Replacement of baby’s blood with donor blood. Tiny quantities out by removal of baby’s blood and transfusion of donor blood

Extra Corporeal Membrane Oxygenation (ECMO)

A machine that supports heart and lung function when other treatments do not work.

Extremely Low Birth Weight (ELBW)

Babies born weighing less than 1000g (2lbs).

Extremely Premature

Babies born between 24 and 28 weeks in the womb.


Removal of the endotracheal or breathing tube.

Eyelid speculum

Instrument to hold open the eyelid.

Foetal Alcohol Syndrome (FAS)

A set of physical and mental problems in a baby that occur as a result of a mother drinking alcohol whilst pregnant.


Soft but tough membrane which covers the top parts of the baby's head where the bones have not yet joined together (fusing of the skull takes about 9-18 months).

Fortified Expressed Breast Milk (FEBM)

Breastmilk with special nutrients added to aid growth.

Gastroesophageal Reflux Disease (GERD)

A condition in which the content of the stomach leak backwards from the stomach into the esophagus (the tube from the mouth to the stomach). This gastric reflux can cause heartburn, dyspepsia, and possible injury to the mucous membranes lining the esophagus.


A common antibiotic.


The time a baby spends in the womb

Premature:  born before 37 weeks

Moderately premature:  born between 35-37 weeks

Very premature:  born between 29-34 weeks

Extremely premature:  born between 24-28 weeks

Grams (gms)

Metric unit of weight:
450 grams = 1 pound
1 kilogram (kg) = 2.2 pounds


The noise a newborn baby makes if he or she is having some problems breathing.

Haemolytic disease

Disease causing breakdown of red blood cells.



Head box

A plastic hood placed over the baby's head to allow them to have oxygen.

Head scans

Ultra sound examination carried out regularly to make sure that the baby's head is growing as expected and to examine any signs of damage to the brain.

Heart murmur

A whooshing sound made by blood in the heart, usually heard with a stethoscope. This may or may not be an issue for the baby.


Inflammation of the liver

High Frequency Ventilation (HFV)

A type of ventilation that gently vibrates the baby's chest and gives hundreds of tiny breaths per minute to hold the (air sacs) alveoli in the lungs open.

High Tone

Involuntary muscle contractions; tight rather than floppy muscles.


Extra moisture added to the air inside an incubator to minimise heat loss in babies of less than 30 weeks gestation. Can make the incubator look steamed up. 

Hyaline Membrane Disease (HMD)

Another name for Respiratory Distress Syndrome.


Water on the brain.

Hydrops (also edema or oedema)

An abnormal accumulation of fluid beneath the skin or in one or more cavities of the body that produces swelling.


Condition involving excessive glucose (sugar) levels in the blood.


High blood pressure.


Raised body temperature due to failed thermoregulation. The opposite of hypothermia.


Condition involving reduced glucose (sugar) levels in the blood.


Reduced body temperature.


Lack of oxygen supply to the body generally or a a particular region. Pre-term babies are prone to hypoxia as the lungs are among the last organs to develop during pregnancy. 


When an intravenous needle slips out of a vein, allowing IV fluid to accumulate in the surrounding tissue.


Fluids or drugs that are transferred into the body intraveneously  i.e. directly into a vein.


A hormone produced by the body which causes cells in the liver, muscle, and fat tissue to take up excess glucose from the blood, storing it as glycogen in the liver and muscle. When the body fails to control insulin levels it may be administered medically in some forms of diabetes.

Intermittent Mandatory Ventilation (IMV)

A form of ventilation where a set number of breaths is given per minute by the ventilator.

Interuterine Growth Retardation (IUGR)

Babies born too small for their gestational age.

Intracranial haemorrhage

Bleeding into the fluid-filled spaces of the brain or into the substance of the brain itself.

Intravenous (IV)

A tiny plastic tube or metal tube (straw-like) placed in a vein, through which fluids and nutrients are given.

Intraventricular Haemorrhage (IVH)

Bleeding in and around the hollow parts (ventricles) of the brain.


The insertion of a tube into the body to add or remove fluids or air. Intubation into the windpipe (trachea) may be through the mouth (endotracheal intubation) or through the nose (nasotracheal intubation)


Decrease in blood supply, due to obstruction of arterial blood flow or to or a spasm of the artery.


Yellowish colouring to the skin and whites of eyes caused by increased bilirubin in the blood. Treatment for jaundice is phototherapy and very occasionally exchange transfer.

Kangaroo Care

Holding the baby directly against the skin in order to keep the baby warm and also to soothe the baby.

Long Line

A tiny catheter threaded into a deep vein to give long-term fluids or intravenous nutrition.

Lumbar Puncture (LP) or Spinal Tap

A procedure where a sample of spinal fluid is obtained by placing a needle in the small of the back, between vertebrae (the back bones) to take some spinal fluid for testing.


Baby’s first bowel movement. It is thick, sticky and greeny black in colour.

Meconium Aspiration

The inhalation (breathing in) of meconium into the lungs.  If a baby inhales meconium into its lungs before delivery it can cause problems with breathing when born. This condition is called Meconium Aspiration Syndrome (MAS)

Magnetic Resonance Imaging (MRI)

A computerised image used to view any part of the body not using X-ray but magnetism


A serious infection of the fluid that surrounds the brain and the spinal fluid.

Muscle relaxant

A drug used to relax muscles, used to ease muscle spasm and to help intubation and ventilation.

Nasal Prong or Cannula

A small tube put into the nostrils (nose) to deliver oxygen.

Naso Gastric Tube (NGT)

A feeding tube which goes from the baby's nose to the stomach.

Necrotising enterocolitis (NEC)

A serious condition, infection of the wall of the intestine causing bleeding into the gut, sepsis and occasionally perforation of the gut and peritonitis.


A specialized area of medicine concerned with diseases of newborn babies (neonates).  Neonatologists are paediatricians who have received extra training.

Nothing (or Nil) By Mouth (NBM)

No feeding/drinking through the mouth. Also known as NPO
from the Latin, nil per os, meaning nothing by mouth.


The loss of a baby at a gestation of less than 24 weeks.

Oedema (also edema or hydrops)

An abnormal accumulation of fluid beneath the skin or in one or more cavities of the body that produces swelling.


Muscular tube that carries food from the mouth to the stomach.


A medical doctor who specializes in eye disorders.

Oro Gastric Tube (OGT)

A feeding tube going from the baby's mouth to stomach.

Patent Ductus Arterious (PDA)

In the womb a baby has a small vessel which allows blood to bypass the lungs. This normally closes shortly after delivery. When this vessel does not close by itself either medication or surgery is needed.

Percutaneously Inserted Central Catheter (PICC)

A long, very thin, soft plastic tube that is placed in a small blood vessel   to deliver fluids and medicine over a long period of time.  (A regular IV usually lasts only 1 - 3 days before needing to be replaced whereas a PICC can often be kept in for 2 - 3 weeks, or longer.) 

Peak Inspiratiory Pressure (PIP)

The highest pressure that is delivered to the baby by the ventilator during a forced breath.


Wavelike muscular contractions that help to move food down the digestive system.

Periventricular Leukomalacia (PVL)

A type of brain injury which is more common in premature infants than in full-term infants. The condition involves the death of small areas of brain tissue around fluid-filled areas called ventricles.  

Phenylketonuria (PKU)

A genetic disorder in which the body cannot handle essential amino acids. All babies are tested for PKU.


An ultra violet light that is used to treat babies with jaundice.


Leakage of air from the passageways of lung into the space around the lung, causing a partial or total collapse of the lung.


Infection of the lung, or part of the lung.

Premature Baby

A baby born before 37 weeks gestation (in the womb)


What to expect in the future


Stomach contents flow back up into the oesophagus

Respiratory Distress Syndrome (RDS)

Breathing problem in premature babies caused by insufficient surfactant in the baby’s lungs making the lungs stiff.

Retinopathy of Prematurity (ROP)

Blood vessels and scar tissue that forms in the back of eye of preterm babies.

Saturation (SaO2)

Measurement of the level of oxygen in the blood.


Electrical activity in the brain causing involuntary muscle activity or stiffening.


Infection of the blood

Serum Bilirubin Level

The level of jaundice in the blood.


Saliva and mucus coughed up from the airways. 


Birth of a baby that has died in the womb at a gestation of more than 24 weeks.


A temporary opening in the abdominal wall which allows a tube and external bag to be connected to the intestine to collect waste materials. 


The process where secretions are removed from a baby's mouth or nose with a little tube.


A  liquid that coats the inside of the lungs. It helps keep them open so that an infant can breathe in air once he or she is born. Infants who have RDS (see below) are given surfactant until their lungs have developed enough to start making their own surfactant.

Synchronised Intermittent Mandatory Ventilation (SIMV)

A type of ventilation where the ventilator breaths are timed to the baby's breathing pattern.


A baby that has spent between 37 and 41 weeks in the womb.


Blood clot

Total Parenteral Nutrition or Parental Nutrition (TPN)

Nutrition given intravenously.


Temperature, Pulse and Respiration.


The tube (windpipe) that joins the mouth and nose to the lungs via the larynx.


A surgical opening in the windpipe (trachea) to allow air to enter the lungs.


Faster than normal heart rate.


Faster than normal breathing rate.


Giving donated blood by vein or artery

Transient Tachypnoea  (TTN)

A short term breathing problem in newborn babies.


Ultrasonic waves used to create images of internal organs and structures, used for examination purposes

Umbilical Artery Catheter (UAC) or Umbilical Venous Catheter (UVC)

Tube inserted into baby's umbilicus (belly button) in vein or artery, used to give intravenous feeds and take blood samples and record blood pressure.


Using a machine for breathing.


A life support machine that maintains a baby's breathing.


A small cavity,  such as the lower chambers of the heart and the four cavities of the brain.

Very Low Birth Weight

Baby born weighing less than 1500g (3lbs)


A picture is taken to check baby. The most common is a chest X-ray to check lungs or tummy.


Warning about this information sheet

Our aim in preparing this sheet is to provide parent-friendly information that is easy to understand. This information sheet has been prepared by a parent of a premature baby who does not have any medical background or qualifications.  Please do not rely on it. You should always seek the advice of a doctor or medical staff and talk to them about any questions or concerns you have about your baby.

Help with this information sheet
If you spot something that is incorrect, needs updating, amending or improving or know of some useful links please email us, as we would like to keep these sheets relevant and useful.