Meconium and Meconium Aspiration

Meconium and Meconium Aspiration

According to Kaneshiro (2009), meconium is a dark greenish black sticky and tarry substance that is comprised of amniotic fluid, muscus, lanugo (early hair lining the baby's body), bile and skin and intestinal tract cells that have been shed by the baby. Meconium is the first feces that a newborn passes and can be released within the womb during the early phases of pregnancy and typically again sometime within the first few days after birth.

Throughout pregnancy, the baby is situated within the mother's uterus and is surrounded by amniotic fluid. The fluid provides a cushion for the fetus during its stages of rapid growth and development. The baby swallows the amniotic fluid while other constituents are filtered out and remain in the intestine while the amniotic fluid is absorbed and ultimately rereleased within the uterus when the fetus urinates. It is through this process that the amniotic fluid is kept healthy, clear, and clean for the fetus. Within the uterus, it is possible for the fetus to release a stool or meconium into the amniotic fluid and for this meconium to be ingested by the fetus. When passed in utero, meconium can pose significant danger to the fetus.

There is no way to determine if meconium has passed in utero until the birth of the baby. Typically, when the amniotic sac or bag of fluids breaks, the color of the fluid is the first indicator of potential meconium in-utero release. The color of the fluid should be clear, and one with meconium is typically yellow or green. If yellow, the meconium has likely been inside the uterus for an extended amount of time. If green, the meconium has more than likely been recently released and contains particles that can cause a greater health risk to the baby.

During labor and delivery, if the presence of meconium has been noted, the physician will be prepared with a DeLee Suction which is a tool used before the baby takes the first significant breath after the birthing process. This allows for removal of any meconium still present in the airway prior to lung expansion and thereby avoiding respiratory aspiration.

Meconium Aspiration Syndrome (MAS) is a syndrome that can take place at a variety of times. Before, during or after birth, a newborn can inhale meconium. Typically the meconium is mixed with amniotic fluid. Once the newborn inhales the meconium it has the ability to obstruct the airways and thereby makes breathing difficult for the newborn. The breathing process can be affected in a number of ways including chemical irritation of the lungs tissue, complete obstruction of the airway by a meconium plug, infection, and hindrance of the lung surfactant thereby precluding the lungs from expanding properly.