Meconium is the name of the baby’s first poop, which is present as a thick liquid in the intestines of the baby before its birth (1). Most of times, the babies poop it out after they are born. Fetal distress can cause the meconium to be passed before birth, in the mother’s womb where there is a risk of aspirating it and causing problems with breathing and potentially lung infection in the newborn (1).
Meconium can be dark green to brown or black in color. It is the fecal material that is produced in the intestines of the fetus before it is born. After the birth, the baby will pass the meconium stools for the initial couple of days.
So, any kind of stress to the baby before birth or during the birth can result in passing of the meconium stool while the baby is still in the womb. This meconium gets mixed with the amniotic fluid which the fetus breathes in. So, the baby can aspirate the amniotic fluid and meconium mixture into their lungs before, during, or immediately after the birth resulting in what is known as meconium aspiration or meconium aspiration syndrome (MAS) (1, 2).
Although meconium aspiration is not necessary fatal; however, it can cause substantial health problems for the baby. If the meconium aspiration syndrome is not treated or is severe, then it can be life threatening (2).
What are the Causes and Risk Factors for Meconium Aspiration Syndrome?
Meconium aspiration is caused by fetal stress, which in turn occurs when the oxygen supply to the fetus is reduced. Some of the common causes of stress to the unborn baby are:
- Long or difficult labor.
- Post dated pregnancy (more than 40 weeks).
- Some health issues of the mother, such as diabetes or hypertension.
The fetus starts to produce meconium in their intestines only later in the pregnancy. So, if the pregnancy extends beyond its due date, the risk of the fetus to be exposed to meconium gets increased. As the pregnancy extends to its due date and gets past it, there is reduction in the amount of amniotic fluid, which leads to increase in the concentration of the meconium, if the baby passes it. As a result, meconium aspiration syndrome is more common in postdated or overdue babies when compared to the term babies. Meconium aspiration is rare in preterm babies.
What are the Symptoms of Meconium Aspiration Syndrome?
The most prominent symptom of meconium aspiration is respiratory distress. The newborn baby can grunt during breathing or breathe rapidly. In some cases, the baby can stop breathing if the meconium blocks their airways. Other symptoms which indicate that the baby has meconium aspiration are: limpness, cyanosis and low blood pressure.
How is Meconium Aspiration Syndrome Diagnosed?
Diagnosis of meconium aspiration is made by the doctor by observing the symptoms of the newborn and the presence of meconium in the amniotic fluid. The doctor will listen to the infant’s chest using a stethoscope to detect any abnormal breathing sounds. Other ways to confirm the diagnosis of meconium aspiration syndrome are (3):
- Chest x-ray of the baby to see if the meconium has entered the lungs of the newborn (2).
- Blood gas test to assess the levels of oxygen and carbon dioxide.
How is Meconium Aspiration Syndrome Treated?
In case of meconium aspiration, the newborn needs immediate treatment for removing the meconium from its upper airways so the baby can breathe normally. As soon as the baby is born, the doctor will suction the mouth, nose and throat immediately.
If the baby isn’t breathing or not responding, then tube can be placed in the windpipe of the baby to extract the fluid that has meconium in it that is lodged in the windpipe (3, 4). The doctor continues to suction till all the meconium is removed.
If even after all this is done and the baby is still not breathing or has a decreased heart rate, then the doctor will use a bag and mask to deliver oxygen to the newborn, which will help in inflating the lungs so the baby can breathe.
If the infant cannot breathe on its own or is sick, then a tube will be placed in windpipe of the baby to help them breathe.
After the baby has received emergency treatment for meconium aspiration syndrome, then the newborn can be placed in a special care unit for further observation. Some additional treatment can be done to prevent the complications from meconium aspiration and these are (3):
- Oxygen therapy is given to ensure the baby has sufficient oxygen in the blood.
- Antibiotics can be given to treat or prevent an infection.
- A radiant warmer is used to maintain the body temperature of the infant.
- Ventilator can be used to help the newborn breathe.
- If the newborn is not responding to any treatments or has hypertension in the lungs, then extracorporeal membrane oxygenation (ECMO) is done.
What are the Complications of Meconium Aspiration Syndrome?
In many cases, meconium aspiration syndrome will not have any long-term health complications. However, MAS is a serious problem, which can have a profound and immediate effect on the health of the newborn. The meconium present in the lungs can result in infection and inflammation. The airways can also get blocked by the meconium leading to over expansion of the lungs, which in turn can cause collapsing or rupturing of the lungs. This will cause the air present within the lungs to accumulate in the chest cavity and surround the lungs, which is known as pneumothorax and it causes difficulty in re-inflating the lungs.
Meconium aspiration syndrome also increases the risk of the baby developing PPHN or persistent pulmonary hypertension of the newborn. Hypertension in the lungs vessels can decrease the blood flow causing problems with breathing in the baby. Persistent pulmonary hypertension of the newborn is a rare, but fatal condition.
Very rarely, acute meconium aspiration syndrome can restrict the oxygen supply to the brain and result in permanent brain damage.
What is the Prognosis for Babies with Meconium Aspiration Syndrome?
The overall prognosis with immediate and right treatment for infants with MAS is good, as babies having mild complications often recover well. Newborns who develop PPHN or brain damage because of meconium aspiration syndrome can suffer from lifelong health problems requiring medical assistance.
How can Meconium Aspiration Syndrome be prevented?
The best way to prevent MAS is early detection, which can be achieved with regular and careful fetal monitoring before birth to determine if the baby is experiencing any distress. In case of fetal distress, the doctor will take steps to reduce the fetal distress during the birth process, which decreases the risk of developing meconium aspiration syndrome. If the baby is experiencing stress, then the doctor will be prepared and take the necessary steps to evaluate and treat the baby immediately after birth if there are any signs of meconium aspiration syndrome.
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