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Meconium Aspiration Syndrome: Symptoms and Treatment

Meconium is a newborn baby’s first feces, which is usually passed in the first couple of days after birth. It is a dark green fecal material that gets produced in the fetus’ intestines before birth. After delivery, a newborn will continue to pass meconium stools for the first couple of days. However, if a baby experiences some kind of stress before or during birth, then it may cause the baby to pass meconium stool while they are still inside the womb. This meconium stool then mixes with the amniotic fluid that is present around the fetus. There is a chance that the baby may breathe in this amniotic fluid and meconium mixture into their lungs, a condition known as meconium aspiration syndrome (MAS). Here are the symptoms and treatment of meconium aspiration syndrome.

Meconium Aspiration Syndrome: Symptoms and Treatment

What is Meconium Aspiration Syndrome (MAS)?

Meconium is the dark green feces that is produced in the baby’s intestines before delivery. After delivery, these meconium stools continue to be passed for the first couple of days.

However, in some cases, stress can cause the fetus to pass meconium stool while they are still in the womb. This meconium stool mixes with the surrounding amniotic fluid. There is a chance that the baby may breathe the amniotic fluid and meconium mixture into their lungs before, during, or right after the delivery. This condition is known as meconium aspiration syndrome (MAS).(1)

Even though meconium aspiration is not a life-threatening condition, it may still cause significant health complications in the newborn. Furthermore, if this condition is left untreated or it is severe, it can prove to be fatal for the baby.

Causes of Meconium Aspiration Syndrome?

Meconium aspiration may happen in babies when they undergo a stressful experience. Stress occurs when the amount of oxygen available to the baby is decreased. Some of the common causes of fetal stress are:(2)

  • Difficult or a long drawn out labor
  • A pregnancy that has gone past the due date, or has crossed more than 40 weeks
  • Health issues in the mother, including high blood pressure or gestational diabetes
  • An infection

The fetus does not produce meconium until the later stages of pregnancy, and as pregnancy starts to go well past the due date, the higher is the risk of the fetus being exposed to meconium.

As pregnancy crosses the due date, the amount of amniotic fluid also starts going down, thus concentrating the meconium amount. As a result of this, meconium aspiration is more common in newborns that are overdue as compared to babies who are born at full term. Meconium aspiration is rarely seen in preterm babies.

Symptoms of Meconium Aspiration Syndrome

Respiratory distress or breathing difficulties are the most common symptom of meconium aspiration syndrome. The baby might grunt while breathing or maybe breathing rapidly. Many babies may even stop breathing altogether if their airways get blocked by the meconium. The baby may also show the following symptoms:

Diagnosing Meconium Aspiration Syndrome

The diagnosis of meconium aspiration syndrome is made based on the baby’s symptoms and the presence of meconium in the amniotic fluid.(3) The doctor will listen to the newborn’s chest using a stethoscope to detect sounds of any abnormal breathing. Some of the standard methods of confirming the diagnosis of meconium aspiration include:

  • Chest X-ray to check if meconium has entered the baby’s lungs
  • A blood gas test to determine the oxygen and carbon dioxide levels in the newborn’s body

Treatment of Meconium Aspiration Syndrome

In the cases where a newborn is born with meconium aspiration syndrome, they will need urgent medical treatment to remove the meconium from their upper airways. After the delivery, the doctor will perform a suction of the mouth, nose, and throat. This is the first step in treatment.

If the baby is still not responding well or breathing, then a tube might need to be placed in the newborn’s windpipe to allow doctors to suction the fluid that is stained with meconium from their windpipe. The suctioning may continue until no further meconium is observed in the material that is being removed from the trachea.

If the newborn is still not able to breathe or has a low heart rate, then the doctor will use a bag and mask to help the baby breathe. This will help deliver oxygen to the baby and also inflate their lungs, allowing them to breathe better.

The doctor may need to place a tube in the trachea of the baby to help them breathe. This is done in cases where the baby is very sick or not able to breathe on their own.

After such type of emergency treatment is provided, the newborn is likely to be placed in a special care unit or the neonatal intensive care unit (NICU) to observe their breathing. Further treatment might be needed to avoid any complications of meconium aspiration. The five most commonly used treatments include:

  • Use of a ventilator, which an artificial breathing machine to help the newborn breathe
  • Oxygen therapy to ensure the baby is getting enough oxygen in the blood
  • Use of a radiant warmer to help maintain the body temperature of the newborn
  • Using antibiotics such as gentamicin and ampicillin to treat or prevent an infection
  • ECMO (Extracorporeal Membrane Oxygenation) is used if the infant is not responding to any of the other treatments or has developed high blood pressure in the lungs. In ECMO, a pump and machine that carries out the function of the lungs will do the work for the baby’s heart and lungs. This allows time for these organs to heal in the meantime.

Are There Any Complications of Meconium Aspiration Syndrome?

In most cases, newborns with meconium aspiration do not go on to have any long-term health complications. However, this condition is a severe issue that affects the immediate health of an infant. Meconium present in the lungs can lead to infection and inflammation.

Meconium can also block the airways, causing the over expansion of the lungs. If a lung over inflates or expands, it can collapse or rupture. In such a scenario, air from inside the lung can start building up in the chest cavity and around the lung as well. This condition is known as pneumothorax. It can make it challenging to re-inflate the lung, especially in a newborn.

Meconium aspiration also increases the risk of the baby developing persistent pulmonary hypertension of the newborn. This condition is characterized by high blood pressure within the blood vessels of the lungs. This restricts blood flow to the lungs, making it difficult for the child to breathe. However, persistent pulmonary hypertension of the newborn is a rare condition, but it can prove to be fatal.(4)


Early detection of meconium in the amniotic fluid is necessary for preventing meconium aspiration syndrome. Ensuring proper fetal monitoring before delivery can help doctors determine if the baby is under stress. Doctors can also take several steps to relieve fetal distress during labor, thus reducing the likelihood of meconium aspiration to develop. If the baby is under stress, then your doctor should be well prepared to check and treat the newborn immediately if there are any symptoms of meconium aspiration syndrome.


  1. Katz, V.L. and Bowes Jr, W.A., 1992. Meconium aspiration syndrome: reflections on a murky subject. American journal of obstetrics and gynecology, 166(1), pp.171-183.
  2. Wiswell, T.E. and Bent, R.C., 1993. Meconium staining and the meconium aspiration syndrome. Pediatr Clin North Am, 40(5), p.955.
  3. Cleary, G.M. and Wiswell, T.E., 1998. Meconium-stained amniotic fluid and the meconium aspiration syndrome: an update. Pediatric Clinics of North America, 45(3), pp.511-529.
  4. Levin, D.L., Heymann, M.A., Kitterman, J.A., Gregory, G.A., Phibbs, R.H. and Rudolph, A.M., 1976. Persistent pulmonary hypertension of the newborn infant. The Journal of pediatrics, 89(4), pp.626-630.

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Team PainAssist
Team PainAssist
Written, Edited or Reviewed By: Team PainAssist, Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:July 12, 2023

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