Meconium aspiration syndrome

Last reviewed: 28 Aug 2022
Last updated: 29 Mar 2022

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
More key diagnostic factors

Other diagnostic factors

  • grunting
  • chest retractions
  • rales
  • rhonchi
  • tachycardia
  • hypotension
Other diagnostic factors

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
More risk factors

Diagnostic investigations

1st investigations to order

  • CXR
  • CBC
  • CRP
  • blood culture
More 1st investigations to order

Investigations to consider

  • dual pulse oximetry
  • ABG (pH, PaO₂, PaCO₂)
  • echocardiography
  • cranial ultrasound
  • electroencephalogram
  • urinalysis
More investigations to consider

Treatment algorithm

ACUTE

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)
Dharmapuri Vidyasagar

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.

  • Meconium aspiration syndrome images
  • Differentials

    • Transient tachypnea of the newborn
    • Surfactant deficiency
    • Persistent pulmonary hypertension
    More Differentials
  • Guidelines

    • Neonatal resuscitation: 2020 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care, part 5
    • Management of meconium at birth
    More Guidelines
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