Meconium Aspiration
Every expectant parent hopes for an uncomplicated birth and a healthy baby. But some babies do face delivery room complications. One condition that may affect a newborn's health is meconium aspiration, also referred to as meconium aspiration syndrome (MAS). Although it can be serious, most cases of MAS are not.
About Meconium Aspiration
MAS can happen before, during, or after labor and delivery when a newborn inhales (or aspirates) a mixture of meconium and amniotic fluid (the fluid in which the baby floats inside the amniotic sac). Meconium is the baby's first feces, or poop, which is sticky, thick, and dark green and is typically passed in the womb during early pregnancy and again in the first few days after birth.
The inhaled meconium can partially or completely block the baby's diabetes,
meconium or dark green streaks or stains in the amniotic fluid
discoloration of the baby's skin - either blue (cyanosis) or green (from being stained by the meconium)
problems with breathing - including rapid breathing (tachypnea), labored (difficulty) breathing, or suspension of breathing (apnea)
low heart rate in the baby before birth
low neonatal intensive care unit (NICU) to be closely monitored for the next few days. Treatments may include:
- oxygen therapy by oxygen hood or ventilation
- antibiotics
- use of surfactant
- nitric oxide
- obtaining blood routinely to determine if the baby is receiving enough oxygen
Babies who have severe aspiration and require mechanical ventilation are at increased risk for bronchopulmonary dysplasia, a lung condition that can be treated with medication or oxygen. Another complication associated with MAS is a collapsed lung. Also known as pneumothorax, a collapsed lung is treated by reinflating the lung (inserting a tube between the ribs, allowing the lung to gradually re-expand).
Although rare, a small percentage of babies with severe MAS develop aspiration pneumonia. If this occurs, the doctor may recommend advanced lung rescue therapy.
Three therapies are currently used to treat aspiration pneumonia and severe forms of MAS:
- Surfactant therapy - An artificial surfactant is instilled into the baby's lungs, which helps to keep the air sacs open.
- High-frequency oscillation - This special ventilator vibrates air enriched with extra oxygen into the baby's lungs.
- Rescue therapy - Nitric oxide is added to the oxygen in the ventilator. It dilates the blood vessels and allows more blood flow and oxygen to reach the baby's lungs.
If one of these therapies (or a combination of them) doesn't work, there is another alternative. Extra corporeal membrane oxygenation (ECMO) is a form of cardiopulmonary bypass, meaning that an artificial heart and lung will temporarily take over to supply bloodflow to the baby's body. ECMO reduces the fatality rate for these severely distressed infants from 80% to 10%. Not all hospitals are ECMO centers, so babies that require ECMO may need to be moved to another hospital.
Babies with severe cases of MAS may come home from the hospital on oxygen. They may be more likely to have wheezing and lung infections during their first year, but lungs can regenerate new air sacs, so the long-term prognosis for their lungs is excellent.
Severely affected babies are at risk for developing chronic lung disease and may also have developmental abnormalities and hearing loss. Babies diagnosed with MAS will be screened at the hospital for hearing problems or neurological damage. Although very rare, severe cases of MAS may be fatal. Studies have indicated that deaths from MAS have decreased significantly through interventions such as suctioning and reducing the number of post-term births.
Prevention
It's important for a pregnant woman to tell her doctor immediately if meconium is present in the amniotic fluid when her water breaks, or if the fluid has dark green stains or streaks. Doctors also use a fetal monitor during labor to observe the baby's heart rate for any signs of fetal distress. In some cases doctors may recommend amnioinfusion, the dilution of the amniotic fluid with saline, to wash meconium out of the amniotic sac before the baby has a chance to inhale it at birth.
Although MAS is a frightening complication for parents to face during the birth of their child, the majority of cases are not severe. Most infants are monitored for fetal distress during labor, and doctors pay careful attention to any signs that would indicate meconium aspiration. If it does occur, treatment will begin immediately.
For most infants who have inhaled meconium, early treatment can prevent further complications and help to reassure anxious new parents.
Reviewed by: Michael L. Spear, MD