Meconium is the first stool your baby will pass. It is a thick, green, tar-like substance that lines the intestines during your pregnancy. Most babies will have their first bowel movement within a few hours after birth. Occasionally meconium stools will be passed while your baby is still in utero.
If this happens your baby will need to be vigorously suctioned after birth to ensure that your new baby doesn't inhale any meconium into the lungs. Inhaling meconium can lead to aspiration pneumonia. As meconium passed prior to birth can indicate fetal distress, your birth team will monitor you more closely during labor to ensure your baby is tolerating labor.
Meconium can also be a problem to get off your baby's bottom. I highly recommend using something on the diaper area of your newborn to help you during diaper changes. You can use petroleum jelly, unpetroleum jelly, baby oil, or nearly any diaper cream. This just makes diaper changes a bit easier on you and the baby.
Photo © Robin Elise Weiss