Meconium is a newborn's first poop. This sticky, thick, dark green poop is made
up of cells, protein, fats, and intestinal secretions, like bile. Babies typically
pass meconium (mih-KOH-nee-em) in the first few hours and days after birth. But some
babies pass meconium while still in the womb during late
What Is Meconium Aspiration Syndrome?
Meconium aspiration syndrome (MAS) happens when a newborn
has trouble breathing because meconium got into the lungs.
Meconium can make it harder to breathe because it can:
clog the airways
irritate the airways and injure lung tissue
block surfactant, a fatty substance that helps open the lungs after birth
With treatment, most babies with meconium aspiration syndrome get better with no
What Causes Meconium Aspiration Syndrome?
Meconium aspiration happens when a baby is stressed and gasps while still in the
womb, or soon after delivery when taking those first breaths of air. When gasping,
a baby may inhale amniotic fluid and any meconium in it.
Babies who are stressed by low oxygen levels or infections also may pass meconium
before birth. When meconium gets in the amniotic fluid, there's a chance a baby will
breathe (aspirate) it into the lungs before, during, or after birth. But most babies
with meconium in the amniotic fluid will not get MAS.
What Are the Signs & Symptoms of Meconium Aspiration Syndrome?
Before or at a baby's birth, doctors will notice one or more of these signs:
The amniotic fluid is meconium-stained (green).
The baby has meconium stains.
The baby has breathing problems or a slow heart rate.
The baby is limp.
How Is Meconium Aspiration Syndrome Diagnosed?
Doctors diagnose MAS in any baby with breathing problems who is born through meconium-stained
fluid and has no other cause for the breathing problems. A chest
X-ray can confirm the diagnosis. Doctors may do other tests to be sure nothing
else causes the symptoms, such as a heart problem or pneumonia.
A baby who gets extra oxygen but still struggles to breathe will get help from
a breathing machine (ventilator). An infant with severe MAS may need more treatment,
surfactant to help open lungs
inhaled nitric oxide. This gas is added to oxygen to open blood vessels and improve
extracorporeal membrane oxygenation.
The ECMO machine, using a pump that works like the heart, pumps blood from the body
through an artificial lung. Like a normal lung, it adds oxygen to the blood and removes
carbon dioxide. Then the machine sends the blood back to the child.
Most babies with MAS get better within a few days or weeks, depending on how much
meconium they inhaled.
Can Meconium Aspiration Syndrome Be Prevented?
If a woman goes past her due
date, her doctor may recommend inducing
labor to help prevent MAS. If a pregnant woman's water breaks and she sees dark
green stains or streaks in the fluid, she should tell her doctor right away. This
is a sign that meconium is in the amniotic fluid.
In the past, doctors sometimes did amnioinfusion (using saline to dilute meconium
in the amniotic fluid) or suctioned meconium out of the baby's mouth and throat at
birth. But these treatments weren't found to prevent MAS, so are not routinely done.
What Else Should I Know?
Most infants with meconium aspiration syndrome recover completely. Some babies
may have a higher risk of lung infections and wheezing, particularly in their first
year of life.