During pregnancy, an unborn baby ingests amniotic fluid and excretes it daily, which passes through the mother’s kidneys and urination. This built-up of material is called meconium and is the first stool a baby passes (1a).
Sometimes babies will pass their first stool, meconium, while they are still in utero. Depending on how soon it is before the mother gives birth, it could be potentially dangerous. A baby who becomes stressed for some reason during pregnancy may pass the meconium which then becomes mixed with amniotic fluid and something the baby can get into the lungs if not handled properly (1b).
There is no way to know if meconium has passed until the birth of the baby. When the amniotic sac, or water, breaks, the color of it tells the story. A normal color would be a clear one and one with meconium could be either green or yellow. A yellow color indicates the meconium is very old and has been inside the uterus for an unknown amount of time. A green color means it is more recent and if it has particles to it, poses more of a health risk to the baby (1c).
When meconium is noticed during labor and delivery is imminent, the practitioner will be ready with what is called a DeLee suction which is used before the baby takes the first breath after birth. Any meconium that might be present in the baby’s airway needs to be suctioned out before the lungs expand or the meconium will be aspirated into the respiratory system (1d).
The baby may gasp, from distress, in utero and cause meconium to go further into the airway since babies do not fully expand their lungs until after birth and doing so prior is dangerous.Once meconium has been aspirated into the lungs, it can cause a chemical pneumonia. These babies are at high risk of becoming very sick rather quickly. Babies with meconium aspiration will need antibiotics to treat infection and oxygen to help them breathe until they can do so unassisted (1e).
There is no way to prevent meconium from being passed before birth so new mothers should spend no time worrying about it. If it does happen, having a competent practitioner who can handle the situation is the best prevention of further difficulties.