Meconium Aspiration Syndrome: Causes, Treatment, and Aftereffects

Meconium aspiration syndrome (MAS) is a serious illness that occurs while the fetus is still in the uterus and occurs in about 5 to 10% of all pregnancies. What are causes, is there treatment, and what are the aftereffects?

What is meconium aspiration syndrome?

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Meconium aspiration syndrome (MAS) is a disease that causes respiratory problems in the fetus in utero or postpartum. While the fetus is surrounded by amniotic fluid in the mother’s uterus, the fetus expels meconium (stools) into the amniotic fluid and then breathes it in, causing meconium to accumulate in the lungs and the air duct.

Accumulation of meconium in the lungs and air duct usually don’t have any effects, but sometimes they can lead to more serious problems – the baby’s lungs might rupture or become inflamed. The time taken for the baby to become healthy again after treatment depends on how serious the symptoms are. Meconium-stained amniotic fluid (MSAF) is detected in about 10 to 15% of all pregnancies and 5% of MSAF cases are MAS cases.

Causes of meconium aspiration syndrome


Generally, babies do not expel feces into amniotic fluid and move their bowels for the first time only after breastfeeding begins. However, for reasons that have not yet been determined scientifically, the fetus is unable to take in sufficient oxygen and is in hypoxic state, and becomes stressed.

The stress of being in a hypoxic state stimulates the bowels, causes feces to be expelled and the baby swallows up the dirty and murky amniotic fluid. As the reasons why the fetus is unable to take in enough oxygen aren’t known, this makes treatment especially difficult.

Symptoms of meconium aspiration syndrome

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The fetus who is suffering from meconium aspiration syndrome (MAS) at birth will have breathing problems – usually, their breathing is rapid and the baby seems to be grunting when they breathe. Other symptoms include the skin and nails being a yellowish color, or the skin showing signs of cyanosis – “a bluish or purplish discoloration due to deficient oxygenation of the blood”.

To determine if the breathing difficulties or the discoloration is due to meconium aspiration syndrome or not, an X-ray of the baby’s chest will be taken. If the cause of the breathing difficulties is MAS, the chest x-ray will show hyperinflation of the lungs and flattening of the diaphragm.

Are there aftereffects from meconium aspiration syndrome

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In cases where the baby is born covered with meconium, doctors will immediately start working to clear the baby’s mouth, nose and throat of meconium.

A tube will be inserted into the windpipe (trachea) and the intratracheal meconium will be suctioned out. As the meconium in the lungs can cause inflammation or infections, the baby will also be treated with antibiotics.

In most MAS cases, the symptoms aren’t severe and babies usually are kept under observation in a neonatal incubator for a week. Once the baby has no difficulties breathing properly, there is no need to worry about aftereffects as well.

If the symptoms are serious, this could lead to complications like pneumothorax, a condition in which air leaks out of the lungs, or chronic pulmonary hypertension.

Baby will soon be able to breathe properly, so breathe easy!

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There is no way to prevent the baby from falling prey to meconium aspiration syndrome, so only treatment can be administered once the baby is delivered. Although it’s inevitable that you feel worried, remember that your baby feels your stress too as well, so take it easy!