Prematurity

Question 1

What is prematurity?

Answer 1

Preterm birth is defined as delivery before 37 completed week’s gestation.

Question 2

Briefly describe the WHO Classification of prematurity

Answer 2

Preterm birth is defined as delivery before 37 completed week’s gestation. The World Health Organisation defines the different stages of preterm delivery as follows:

• Extreme preterm: before 28 weeks
• Very preterm: 28 to 32 weeks
• Moderate to late preterm: 32 to 37 weeks

Question 3

What is the most common cause of death in neonates?

Answer 3

Prematurity also remains the number one cause of neonatal death globally, and the number one cause of death in under five year olds.

Question 4

What can cause preterm delivery?

Answer 4

There are many overlapping causes that can be attributed to premature delivery:

• Around 25% of preterm deliveries are planned due to life threatening conditions affecting either the mother or foetus (pre-eclampsia, renal disease, severe growth restriction etc)
• Approximately 30-40% are due to premature or prelabour rupture of membranes
• Around 25% are due to an emergency event such as placental abruption, eclampsia or severe infection
• Roughly 40% of the cases have no identifiable cause

Question 5

What are the risk factors for premature delivery?

Answer 5

There are several identified risk factors for premature delivery including (but not limited to):

• Previous preterm delivery
• Multiple pregnancy
• Smoking and illicit drug use in pregnancy
• Being under or overweight in pregnancy
• Early Pregnancy (within 6 months of previous pregnancy)
• Problems involving cervix, uterus or placenta, including infection
• Certain chronic conditions such as diabetes and hypertension
• Physical injury/trauma

Question 6

Briefly describe the Dubowitz/Ballard Examination

Answer 6

The Dubowitz/Ballard Examination for gestational age is an example of an assessment tool which can be used to estimate neonatal maturity. It uses a combination of external physical and neuromuscular features to determine a score. This is then used to give an estimate of a 2 week window of gestation.

Question 7

Following stabilisation and transfer to the neonatal unit, there are several baseline investigations that most premature infants might require during their stay, tailored to each individual patient.

What laboratory investigations should be ordered?

Answer 7

• Blood gas
• Urea, creatinine and electrolytes
• Blood culture
• CRP
• Blood group and Direct Coombs Test/ Direct Antiglobulin Test (DCT/DAT)

Question 8

Why investigate using blood gas?

Answer 8

This is commonly used to help assess the respiratory and metabolic state of the infant and increase or decrease support as needed.

Question 9

Why investigate using FBC?

Answer 9

Preterm infants are at high risk of infection, thrombocytopenia and anaemia, therefore requiring close observation of their WCC, platelets and RBC.

Question 10

Why investigate urea, creatinine and electrolytes?

Answer 10

Many units do not perform renal function tests at initial admission, as this is more likely to be reflective of the mother’s electrolyte balance roughly for the first 24 hours of life. However, electrolyte and fluid balance is paramount for neonatal care and close monitoring of renal function helps to tailor management accordingly

Question 11

Why investigate using blood culture?

Answer 11

Infection can be a risk factor in preterm delivery therefore frequently infants are screened with a blood culture on admission and commenced on intravenous antibiotics. If the baby becomes unwell, they would likely be re-screened as per local protocols.

Question 12

Why investigate CRP?

Answer 12

In view of the association between prematurity and infection, CRP is checked on admission, and monitored during the child’s stay on the neonatal unit. There is a wide range of protocols for this. NICE guidelines also exist suggesting level thresholds for investigations such as LP. Also, preterm infants are at risk of developing infections for many reasons including immature immune systems, multiple invasive procedures and in dwelling central lines to name a few.

Question 13

Why investigate blood group and Direct Coombs Test/ Direct Antiglobulin Test (DCT/DAT)?

Answer 13

Many premature infants require a blood transfusion during their stay in the neonatal unit. Almost all (approximately 80%) will develop jaundice in the first week of life. These tests should be checked with admission bloods.

Question 14

Following stabilisation and transfer to the neonatal unit, there are several baseline investigations that most premature infants might require during their stay, tailored to each individual patient.

What Imaging or invasive tests should be ordered?

Answer 14

• Chest x-ray
• Abdominal x-ray
• Cranial ultrasound scan (CrUSS)

Question 15

Why investigate using chest x-ray?

Answer 15

Almost all infants born before 32 weeks will need some form of respiratory support. A chest x-ray is needed if an infant shows signs of respiratory distress (tachypnoea, oxygen dependency, increased work of breathing). If a baby is intubated and ventilated, a chest x-ray is required to assess the position of the endotracheal tube.

Question 16

Why investigate using abdominal x-ray?

Answer 16

Preterm infants are often in need of parenteral nutrition and several intravenous infusions in the first few days and weeks of life. Therefore, central venous and arterial access are usually inserted through the umbilical vein and arteries. An abdominal and chest x-ray are used to assess the position of the umbilical venous and umbilical arterial catheters after insertion. Preterm infants are also at risk of developing necrotising enterocolitis. If this is suspected, an AP and lateral film may be needed to assess for signs of perforation (free air within the abdominal cavity, football sign, pneumatosis intestinalis, immobile bowel loops in repeat x-rays).

Question 17

Why investigate using cranial ultrasound scan (CrUSS)?

Answer 17

The brains of preterm and very low birth weight infants are at increased risk of neurological insults from haemorrhagic, ischaemic and infective factors. CrUSS is used routinely in infants born at less than 32 weeks to assess for any signs of intraventricular haemorrhage or ischaemic periventricular white matter damage. It has the benefit of being a simple bedside tool which, when used repeatedly and in conjunction with other factors, can help identify those infants most at risk of adverse neurodevelopmental outcomes. This needs to be reviewed with an MRI at a later stage.

Question 18

In women with a history of preterm birth or an ultrasound demonstrating a cervical length of 25mm or less before 24 weeks gestation…what are the 2 treatment options for delaying birth?

Answer 18

In women with a history of preterm birth or an ultrasound demonstrating a cervical length of 25mm or less before 24 weeks gestation there are two options of trying to delay birth:

• Prophylactic vaginal progesterone: putting a progesterone suppository in the vagina to discourage labour
• Prophylactic cervical cerclage: putting a suture in the cervix to hold it closed

Question 19

Where preterm labour is suspected or confirmed there are several options for improving the outcomes… what are these options?

Answer 19

Tocolysis with nifedipine: nifedipine is a calcium channel blocker that suppresses labour.

Maternal corticosteroids: can be offered before 35 weeks gestation to reduce neonatal morbidity and mortality.

IV Magnesium sulphate: can be offered before 34 weeks gestation and helps protect the baby’s brain.

Delayed cord clamping or cord milking: can increase the circulating blood volume and haemoglobin in the baby.

Question 20

Briefly describe the current guidelines for resuscitation in a preterm infant

Answer 20

There is much debate surrounding resuscitation of extreme preterm infants. Current guidelines suggest that if a woman presents in labour at a gestation of:

• Less than 23 weeks then resuscitation should not be performed
• Between 23 and 23+6 weeks then there may be a decision not to start resuscitation in the best interests of the baby, especially if parents have expressed this wish.
• Between 24 and 24+6 weeks, resuscitation should be commenced unless the baby is thought to be severely compromised. Response to initial measures should be considered before the decision is made to commence intensive care.
• After 25 weeks, it is appropriate to resuscitate and start intensive care.

Question 21

What are the early complications in the preterm infant?

Answer 21

• Respiratory distress syndrome
• Hypothermia
• Hypoglycaemia
• Poor feeding
• Apnoea and bradycardia
• Neonatal jaundice
• Intraventricular haemorrhage
• Retinopathy of prematurity
• Necrotising enterocolitis
• Immature immune system and infection

Question 22

What are the long complications in the preterm infant?

Answer 22

• Chronic lung disease of prematurity (CLDP)
• Learning and behavioural difficulties
• Susceptibility to infections, particularly respiratory tract infections
• Hearing and visual impairment
• Cerebral palsy

Question 23

Give examples of respiratory complications in the preterm infant and how these can be managed

Answer 23

Complications:

• Respiratory distress syndrome
• Surfactant deficient lung disease
• Chronic lung disease/ Bronchopulmonary dysplasia
• Recurrent apnoea

Mangement:

• Exogenous surfactant administration
• Endotracheal intubation and mechanical ventilation
• Bilevel positive airway pressure
• Continuous positive airway pressure
• High flow oxygen
• Nasal cannula low flow oxygen
• Ambient incubator oxygen
• Caffeine administration

Question 24

Give examples of cardiovascular complications in the preterm infant and how these can be managed

Answer 24

Complications:

• Hypotension
• Perfusion abnormalities
• PDA

Management:

• Inotrope infusions (including dopamine, dobutamine, adrenaline, and noradrenaline)
• Fluid management
• Ibuprofen or indomethacin administration
• Ligation of PDA (rare)

Question 25

Give examples of neurological complications in the preterm infant and how these can be managed

Answer 25

Complications:

• Intraventricular haemorrhage
• Seizures
• Post haemorrhagic ventricular dilatation
• Neurodevelopmental delay
• Cerebral palsy

Management:

• Regular surveillance with CrUSS
• Regular head circumference measurement
• Administration of antiepileptic drugs (phenobarbital and phenytoin)
• Referral to neurosurgical team if needed
• Long term neurodevelopmental follow up and support as necessary
• Awareness of level of stimulation (handling, noise, light, etc)

Question 26

Give examples of gastrointestinal complications in the preterm infant and how these can be managed

Answer 26

Complications:

• Immature gut causing feed intolerance
• Necrotising enterocolitis (NEC)

Management:

• Total parenteral nutrition (TPN)
• Nasogastric and orogastric feeds
• Maternal and donor expressed breast milk
• Feeding protocols
• Antibiotic therapy
• Surgical review if NEC is suspected

Question 27

Give examples of renal/ electrolyte complications in the preterm infant and how these can be managed

Answer 27

Complications:

• Immature renal function

Management:

• Close monitoring of fluid and electrolyte balance
• Electrolyte supplements when indicated
• Catheterisation if indicated

Question 28

Give examples of metabolic complications in the preterm infant and how these can be managed

Answer 28

Complications:

• Jaundice
• Hyperglycaemia
• Hypoglycaemia
• Inborn errors of metabolism

Management:

• Phototherapy
• Exchange transfusion
• Insulin infusion
• Increase concentration or volume of glucose given via central IV access
• Baseline metabolic investigations (including Guthrie Card)

Question 29

Give examples of infectious complications in the preterm infant and how these can be managed

Answer 29

Complications:

• Sepsis
• Increased risk of infection due to central lines and multiple procedures

Management:

• Septic screen
• Intravenous antibiotic therapy according to local guidelines

Question 30

Give examples of skin complications in the preterm infant and how these can be managed

Answer 30

Complications:

• Immature skin barrier leading to increased insensible losses and increased risk of infection

Management:

• Nursing in a warm, humid incubator, aseptic non-touch technique during procedures

Question 31

Give examples of thermoregulation complications in the preterm infant and how these can be managed

Answer 31

Complications:

• Immature thermoregulation

Management:

• Nursing in a warm humid incubator
• Cot warmer
• Awareness of exposure whilst performing procedures and examinations

Question 32

Give examples of eye complications in the preterm infant and how these can be managed

Answer 32

Complications:

• Retinopathy of prematurity

Management:

• Avoid excessive oxygen exposure
• Screening for retinopathy of prematurity by ophthalmology team
• Laser treatment if indicated

Question 33

Briefly explain the neurodevelopmental outcomes in the preterm infant

Answer 33

The earlier a baby is born, the higher the likelihood that they will have some neurodevelopmental impairment. Impairment can include gross motor delay, fine motor impairment, speech and language delay, learning and behavioural difficulties.

The 3-year follow-up of the EPICure 2 study has shown that, of infants born at 22 weeks, around 1/3 will have no or mild disability. By 26 weeks this increases to around 75%. It was found that around 2/3 of the infants seen in the EPICure study required some support at school, although only 1/8 required attendance at a special school.

This information is important when counselling parents.

Question 34

Briefly explain the family support offered to parents with a preterm infant

Answer 34

Delivery of a preterm infant can cause a mix of emotions for parents and the wider family. It is a time of many ups and downs and support is essential in helping families deal with the stress and unpredictability of having a premature baby.

From an early stage parents, should be invited to be involved in the care of their infant and when the baby is stable enough, periods of kangaroo care/skin-to-skin should be encouraged. There are often local support groups available for parents and charities such as Bliss that offer information and support to families of preterm and sick infants.

Question 35

Briefly explain the end of life care and ethical considerations with regards to preterm infants

Answer 35

Neonatology is a complex, challenging and highly emotive field of medicine. There are unfortunately times when the decision is made to “withdraw” intensive care. End of life care is an important aspect of neonatal medicine.