Paeds · fetal-neonatal-and-perinatal
Meconium aspiration syndrome
Also known as Meconium aspiration · MAS · Meconium-stained amniotic fluid aspiration · Neonatal meconium pneumonitis
Fellowship guide to meconium aspiration syndrome: the pathophysiology of meconium-induced lung injury (airway obstruction, surfactant inactivation, chemical pneumonitis, infection risk), the vigour-based delivery-room algorithm that replaced routine suctioning, the severity-based escalation ladder (oxygen, CPAP, ventilation, surfactant, inhaled nitric oxide, ECMO), recognition and management of persistent pulmonary hypertension of the newborn, and regional guideline differences across ANZ, UK, US and Canada.
On this page
Study tools
Your progress
Saved on this device.
Practise this topic
Target exams
Red flags
- Non-vigorous meconium-stained infant receiving routine intubation-with-suction instead of standard NRP resuscitation — an abandoned, harmful practice
- Hypoxaemia disproportionate to the chest radiograph with a wide pre-/post-ductal saturation gradient — persistent pulmonary hypertension of the newborn
- Sudden deterioration with asymmetrical breath sounds and cardiovascular collapse in a ventilated infant — tension pneumothorax from ball-valve air trapping
- Cord pH below 7.0 with low Apgars and meconium — coexisting hypoxic-ischaemic encephalopathy requiring therapeutic hypothermia assessment within the 6-hour window
- Preterm infant with green-stained liquor — suspect Listeria or intra-amniotic infection rather than true meconium passage
Life stages
Care settings
Clinical exam formats
Board mappings
- Neonatal medicine
- General and Community Paediatrics
- Current 2026 PREP curriculum — newborn care and essential neonatal care
- Renewed curriculum for first-year trainees from 2027 — essential general paediatrics
- Clinical Applications
- Medical Sciences
- Long Cases
- Short Cases
- Patient management
- Health promotion and illness prevention
- Foundation of Practice (FOP)
- Theory and Science (TAS)
- Applied Knowledge in Practice (AKP)
- Clinical
- History
- Communication
- General Pediatrics Content Outline — Domain 1: Preventive Pediatrics/Well-Child Care
- General Pediatrics Content Outline — Universal Task 3: Diagnosis
- General Pediatrics Content Outline — Universal Task 4: Management and Treatment
- Patient Care: neonatal resuscitation and respiratory support
- Medical Knowledge: meconium-induced lung injury pathophysiology
- Systems-Based Practice: perinatal team coordination and retrieval
- Medical Expert
- Health Advocate
- Communicator
Overview & Definition
Meconium aspiration syndrome (MAS) is the clinical syndrome of respiratory distress that develops in a newborn infant born through meconium-stained amniotic fluid (MSAF), with characteristic radiographic findings, when other causes of neonatal respiratory distress have been excluded [7]. The meconium — the neonate's first stool, composed of desquamated intestinal cells, swallowed lanugo, mucus, bile pigments, pancreatic enzymes and water — is passed in utero in the setting of fetal stress or post-maturity and is then aspirated, typically through fetal gasping driven by hypoxia [7].
MAS remains one of the leading causes of term and near-term neonatal respiratory failure. Its hallmark is a triad of MSAF, respiratory distress within the first hours of life, and a chest radiograph showing coarse, patchy infiltrates with hyperinflation and, frequently, air leak. The clinical course ranges from transient tachypnoea requiring minimal oxygen to fulminant respiratory failure complicated by persistent pulmonary hypertension of the newborn (PPHN), pneumothorax and death [7].
References7ShowHide
- [1]Vain NE; Szyld EG; Prudent LM; Wiswell TE; Aguilar AM; Vivas NI Oropharyngeal and nasopharyngeal suctioning of meconium-stained neonates before delivery of their shoulders: multicentre, randomised controlled trial. Lancet, 2004.PMID 15313360
- [2]El Shahed AI; Dargaville PA; Ohlsson A; Soll RF Surfactant for meconium aspiration syndrome in term and late preterm infants. Cochrane Database Syst Rev, 2014.PMID 25504256
- [3]Dargaville PA; Copnell B; Mills JF; Harigopal S; Loughnan PM Lung lavage for meconium aspiration syndrome in newborn infants. Cochrane Database Syst Rev, 2013.PMID 23633311
- [4]Gordon MC; Narula K; O'Shaughnessy R; Barth WH Jr Changing obstetric practices associated with decreasing incidence of meconium aspiration syndrome. Obstet Gynecol, 2002.PMID 11978280
- [5]Eke AC; Okoye JA; Eze BI; Okechukwu ZN Amnioinfusion for meconium-stained liquor in labour. Cochrane Database Syst Rev, 2014.PMID 24453049
- [6]Walsh-Sukys MC Persistent pulmonary hypertension of the newborn. The black box revisited. Clin Perinatol, 1993.PMID 8458161
- [7]Fuloria M; Wiswell TE The meconium aspiration syndrome: the saga continues. Indian Pediatr, 1998.PMID 10216539