Meconium Happens


Gotta go? Babies do too! Meconium is a fancy term for a baby's first poop. Because a newborn has not yet consumed breast milk or formula, meconium consists of some rather unusual contents. Often meconium contains almost everything a baby has consumed while in utero, like skin cells that have been shed, mucus, amniotic fluid, bile, water, and lanugo, which is that fine hair covering a baby’s body at birth. When excreted, this green/black, tar-like substance may stick to the baby as meconium has a very high viscosity; but nothing a little petroleum jelly can’t wipe off, and the good news is...Meconium doesn’t smell!

Typically, the presence of meconium only lasts a day or so, then the baby’s stool will change colors as their digestive system adjusts to breast milk or formula. However, in some cases meconium can occur during labor or delivery. One easy way to determine if this has occurred is through the color of the amniotic fluid. If meconium is present, the amniotic fluid that presents in labor will have a green or brown tint to it. One issue that arises with meconium present is that it mixes with the amniotic fluid surrounding the fetus, this then allows for the possibility of it to be inhaled into the baby’s lungs restricting proper respiration. This condition is known as Meconium Aspiration Syndrome or MAS.

The presence of meconium in the amniotic fluid may not cause any symptoms or complications - the baby can be born kicking and crying which is normally the green-light for mommy and her doctor or midwife. That said, although MAS is often not life-threatening it can cause some complications for a newborn including the possibility for the baby to be born motionless and not breathing due to meconium blocking their respiratory pathway. In this case, a tube is placed in the infant's airway and a suction is then used to remove the meconium causing the blockage. This procedure may need to be repeated more than once depending on the severity. If this treatment is unsuccessful other forms of treatment may need to be utilized, such as a face mask to deliver oxygen, a ventilator, or antibiotics.

In most cases the outlook is exceptional and there are no long term effects. About half of babies with meconium in their amniotic fluid will have respiratory issues and only about 5% will have MAS. The respiratory issues typically diminish in 3-4 days and MAS rarely leads to permanent lung issues. Staying healthy during pregnancy to ensure a more trouble-free birth is the best means of prevention as babies under stress or in utero passed 40 weeks are more likely to excrete meconium sooner than desired.