Paediatrics: Prematurity

2021-03-09 12:00 AM

Birth before 37 completed weeks gestation. 8% of all births. Most problems are seen in infants born <32 completed weeks (72% of all births).

Prematurity

Birth before 37 completed weeks gestation. 8% of all births. Most problems are seen in infants born <32 completed weeks (72% of all births).

Predisposing factors

  • Idiopathic (40%).
  • Previous preterm birth.
  • Multiple pregnancies.
  • Maternal illness, e.g. chorioamnionitis, polyhydramnios, pre-eclampsia, diabetes mellitus.
  • Premature rupture of membranes.
  • Uterine malformation or cervical incompetence.
  • Placental disease, e.g. dysfunction, antepartum haemorrhage.
  • Poor maternal health or socioeconomic status.

Associated problems

  • Respiratory: surfactant deficiency causing respiratory distress syndrome, apnoea of prematurity, chronic lung disease/bronchopulmonary dysplasia (CLD/BPD).
  • CNS: intraventricular haemorrhage, periventricular leucomalacia; retinopathy of prematurity.
  • GI: necrotizing enterocolitis; inability to suck; and poor milk tolerance.
  • Hypothermia.
  • Immuno-compromise resulting in ‘rise' risk and severity of the infection.
  • Impaired fluid/electrolyte homeostasis (i transepidermal skin water loss, poor renal function).
  • Patent ductus arteriosus.
  • Anaemia of prematurity.
  • Jaundice.
  • Birth trauma.
  • Perinatal hypoxia.
  • Later: increased risk of adverse neurodevelopmental outcome, behavioural problems, sudden infant death syndrome (SIDS), non-accidental injury (NAI), and/or parental marriage break up (due to impaired infant–maternal bonding, the stress of long-term complications, etc.).

General management—antenatal

  • Delivery should be planned in a centre capable of caring for preterm infants.
  • If a woman has threatened preterm labour in a centre unable to care for the baby, the possible in-user transfer should involve a discussion between neonatology and obstetrics teams preferably at the consultant level. Consider foetal fibronectin screening to aid diagnosis and tocolysis to delay birth to allow for transfer.
  • Give mother IM corticosteroids, 2 doses, 12–24hr apart, of either beta- or dexamethasone, if <34wks gestation. Steroids ‘fall’ mortality by up to 40% (d severity of RDS, periventricular haemorrhage, and necrotizing enterocolitis) provided they are given >24hr before birth. Benefit persists for at least 7 days. The effect of repeated doses remains unclear—may have an adverse impact on later growth.

General management—postnatal

  • Most preterm infants require stabilization and support in transition– not resuscitation.
  • The senior paediatrician should be present at birth if very preterm, e.g. <28wks.
  • Delay cord clamping for 1min if infant not compromised.
  • Immediately after birth, place in a food-grade plastic bag and under the radiant heater.
  • Provide respiratory support as required:

o use positive end-expiratory pressure (PEEP) (5cmH2O);

o start with lower peak inspiratory pressure or proximal (PIP) (20cmH2O);

o consider elective intubation and ETT surfactant if <27/40;

o may be possible to stabilize with PEEP/nasal continuous positive airway pressure (CPAP) only.

  • Monitor oxygen saturation levels if available (right wrist = pre-ductal), and target oxygen therapy appropriately:

o must be familiar with normal values;

o approx 10% well preterm infants will have SpO2 <70% at 5min;

o ‘correct’ starting dose of O2 unclear, therefore, can start in the air;

o easy to hyper oxygenate if start in high FiO2.

  • Once stable, well infants >1800g, and >35/40 may be transferred to a suitable postnatal ward if midwifery staffing and expertise exist for the required additional care. Otherwise, admit to a neonatal unit.
  • Measure weight and temperature on admission and monitor closely:

o <1000g 37–37.5C;

o >1000g 36.5–37C;

o nurse in 80% humidity for the first 7 days if <30/40.

  • Monitor and maintain blood glucose with enteral feeds (expressed breast milk), total parenteral nutrition (TPN) or 10% glucose as appropriate. Encourage ALL mothers to express breast milk from day 1.
  • Start broad-spectrum antibiotics if any possibility of infection, e.g. benzylpenicillin, and gentamicin.
  • Start specific treatment for associated diseases and complications of prematurity, e.g. surfactant for RDS.
  • Aim for minimal handling of an infant with appropriate levels of noise and cycled lighting in the nursery.
  • Support parents.