Summary
Definition
History and exam
Key diagnostic factors
- signs of postmaturity
- tachypnea
- cyanosis
- systolic murmur
- chest wall asymmetry with decreased air entry
- barrel-shaped chest
Other diagnostic factors
- grunting
- chest retractions
- rales
- rhonchi
- tachycardia
- hypotension
Risk factors
- gestational age >42 weeks
- pregnancy-induced hypertension
- maternal diabetes mellitus
- maternal smoking or substance misuse
- fetal distress
- oligohydramnios
- thick meconium
- Apgar score <7
- chorioamnionitis
- cesarean delivery
- black ancestry
- male sex
Diagnostic investigations
1st investigations to order
- CXR
- CBC
- CRP
- blood culture
Investigations to consider
- dual pulse oximetry
- ABG (pH, PaO₂, PaCO₂)
- echocardiography
- cranial ultrasound
- electroencephalogram
- urinalysis
Treatment algorithm
vigorous infant born through meconium-stained amniotic fluid, no respiratory distress
mild MAS
moderate MAS
severe MAS
Contributors
Authors
Dharmapuri Vidyasagar, MD, MSc, FAAP, FCCM, PhD (Hon)

Professor Emeritus
Department of Pediatrics
University of Illinois at Chicago
Chicago
IL
Visiting Professor
Department of Neonatology
Sri Ramachandra Medical College
Chennai
India
Disclosures
DV is an author of a number of references cited in this topic. He has received royalties for editing the following books: Neonatal Ventilation (Elsevier India), Practical Neonatology (Indian Journal of Pediatrics), and Perinatal Cardiology (Cambridge Scholar publishing).
Rama Bhat, MD, FAAP
Professor of Pediatrics
Department of Pediatrics
University of Illinois at Chicago
Chicago
IL
Disclosures
RB is an author of a reference cited in this topic.
Peer reviewers
James Wynn, MD
Medical Instructor
Department of Pediatrics
Division of Neonatology
Duke University
Durham
NC
Disclosures
JW declares that he has no competing interests.
Henry L. Halliday, MD, FRCPE, FRCP, FRCPCH
Professor
Retired Consultant Neonatologist
Royal Maternity Hospital
Honorary Professor
Department of Child Health
Queen's University Belfast
Belfast
UK
Disclosures
HLH declares that he has no competing interests.
John Sinn, MBBS(Syd), Dip Paed, DCH, MMed (Clin Epi), FRACP (Paed)
Clinical Senior Lecturer
Obstetrics
Gynaecology and Neonatology
Royal North Shore Hospital and The University of Sydney
Sydney
Australia
Disclosures
JS declares that he has no competing interests.
Differentials
- Transient tachypnea of the newborn
- Surfactant deficiency
- Persistent pulmonary hypertension
More DifferentialsGuidelines
- Neonatal resuscitation: 2020 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care, part 5
- Management of meconium at birth
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