Meconium Aspiration Syndrome

By Alison Heyerdahl

Meconium is the thick, sticky, tar-like substance that your baby excretes into her diaper after birth. It comprises the dead skin cells, proteins, fats, intestinal secretions, and all the other matter your baby swallowed while in the womb. After delivery, your baby will pass meconium stools for the first few days of life. Sometimes, if your baby is distressed, she will have a bowel movement before birth and will excrete the meconium into the amniotic fluid. This can present a problem known as meconium aspiration syndrome.

Why do babies pass meconium?

Babies often pass meconium while still in the womb because:

• It’s been a long or stressful birth.

• The mother has high blood pressure or diabetes.

• The baby is born past her due date.

• The mother used drugs or smoked during pregnancy.

• Low oxygen levels stress babies during the birth process.

Note that pregnancies that progress well past the due date can decrease amniotic fluid, concentrating the meconium. It is, therefore, more likely in overdue newborns rather than babies born too early.  

What is meconium aspiration syndrome?

Sometimes the birth process can be stressful for both mother and baby. Any stress your baby experiences can result in her passing the meconium stools while still in the uterus. Meconium mixes with the amniotic fluid, which stains it a greenish color.  

Meconium aspiration occurs when your baby gasps while still in the womb or shortly after delivery and inhales the amniotic fluid and meconium into her lungs. It can cause problems with a baby’s breathing or inflation of the lungs immediately after birth. It can also result in meconium aspiration pneumonia. Signs of meconium aspiration include:

• Signs of respiratory distress such as rapid breathing.

• Low heart rate.

• A bluish skin color associated with a lack of oxygen.

• Limpness or your baby being non-responsive.

Note that not all babies who excrete meconium into the amniotic fluid will get meconium aspiration syndrome.

How is meconium aspiration diagnosed?

Your doctor will often listen to your baby’s chest with a stethoscope to determine whether he/she is breathing abnormally. A chest X-Ray may also be performed to see if meconium has entered the lungs. Other tests, such as a blood gas test, may be carried out to check oxygen and carbon dioxide levels.  

How is meconium aspiration treated?

If meconium aspiration occurs, your baby will need immediate intervention to remove the meconium from her airways. Her nose, mouth, and trachea will be suctioned to remove the fluid. Babies who suffer meconium aspiration syndrome may also get transferred to the neonatal intensive care unit and receive oxygen if need be. In extreme cases, if normal breathing does not resume, your baby may be intubated and placed on a ventilator (a breathing machine). Your doctor may also prescribe antibiotics to curb any potential infections resulting from meconium aspiration.  

Most babies with meconium aspiration syndrome improve within a few days or weeks, depending on how much meconium was aspirated. It does not often cause long-term problems.

How can meconium aspiration be prevented?

If a woman goes one to two weeks beyond her due date, her doctor may recommend inducing labor to prevent meconium aspiration syndrome. Doctors may also suggest that a woman undergoes an emergency C-section if her water breaks and there are signs of meconium in the amniotic fluid. However, this is not always the case, and the doctor will check the baby for other signs of distress, such as a lowered heart rate, to determine if a C-section is necessary.  

Conclusion

Meconium is the dark, sticky tar-like substance your baby produces in her intestines during pregnancy. Meconium is sometimes released into the amniotic fluid if your baby experiences stress during or before the birth process. The presence of meconium in the amniotic fluid can mean that your baby inhales it into her lungs, resulting in meconium aspiration and an inability to inflate the lungs or breathe. Babies who experience meconium aspiration are treated with oxygen therapy, antibiotics, and in extreme events, are placed on a ventilator. In most cases, babies will make a full recovery.