Meconium Aspiration Syndrome
Definition
Meconium aspiration syndrome (MAS) is a set of symptoms that happen when an infant inhales meconium. Meconium is the first stool of an infant. It is sometimes passed into the fluid that surrounds the baby in the womb.
Causes TOP
Not all infants who inhale meconium will have MAS. It is not known why some infants get MAS and others do not.
Risk Factors TOP
Things that may raise a baby’s risk of meconium aspiration are:
- Delivery after 42 weeks
- Cesarean section delivery
- Abnormal heart rate during labor
- Low levels of amniotic fluid
- Low or high birth weight
- Meconium below the baby’s vocal cords
Things in a mother that may raise the chance of meconium aspiration in the baby are:
- High blood pressure
- Diabetes
- Respiratory disease
- Heart disease
- Smoking
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Symptoms TOP
MAS may cause:
- Breathing that is too fast or too slow
- Blue skin color
- Grunting
- Nostrils that spread out when breathing
- Low muscle tone or muscle spasms
Diagnosis TOP
This problem is diagnosed in a newborn based on symptoms and signs of meconium in the fluid. The diagnosis can be confirmed with a chest x-ray. Blood tests will also be done.
Treatment TOP
The overall goal of treatment is to promote breathing. This can be done with:
- Intubation to open the airway and suction it as needed
- Oxygen therapy to ease breathing
- Breathing support in babies who cannot breathe on their own
Medication
Medicines that may be used are:
- Antibiotics to treat infection
- Surfactants to coat the lungs, clear the airways, and help the lungs mature
- Nitric oxide gas to open blood vessels in the lungs to let more oxygen in the body
RESOURCES:
Healthy Children—American Academy of Pediatrics
https://www.healthychildren.org
Kids Health—Nemours Foundation
http://kidshealth.org
CANADIAN RESOURCES:
About Kids Health—The Hospital for Sick Children
http://www.aboutkidshealth.ca
Caring for Kids—Canadian Paediatric Society
http://www.caringforkids.cps.ca
REFERENCES:
Chettri S, Bhat BV, et al. Current Concepts in the Management of Meconium Aspiration Syndrome. Indian J Pediatr. 2016 Oct;83(10):1125-1130.
Meconium aspiration. Kids Health—Nemours Foundation website. Available at:
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Updated November 2019. Accessed December 31, 2019.
Meconium aspiration syndrome. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/meconium-aspiration-syndrome. Updated August 24, 2018. Accessed December 31, 2019.
Last reviewed September 2019 by
EBSCO Medical Review Board
Kari Kassir, MD
Last Updated: 5/29/2020