What is Meconium?
This thick, blackish-green tar like substance is considered your baby’s first stool. Meconium is created from the combination of amniotic fluid, lunugo, mucus, bile, and shed cells that line your baby’s intestines throughout your pregnancy. It usually does not pass until after the baby’s birth; however, sometimes it may occur during labor.
You will know if your baby has passed it’s meconium if your water breaks and the fluid is dark instead of light and clear. This is sometimes referred to as “meconium liquor”. Meconium staining happens in about 13% of birth (1). There are a few reasons for in utero meconium. Meconium staining seen in significantly post-date labors may be a sign of infection in utero or a sign of fetal distress. Should the baby pass the meconium during labor, the care provider will be closely monitoring the baby for distress. One thing the care provider will be looking at in the amniotic fluid is if the staining is light or dark and thick. An excerpt from ‘The New Midwifery’ by Lesley Ann Page explains why:
“Thick meconium is thick because it is not diluted with amniotic fluid, either because of oligohydramnios or because the membranes have ruptured. Reduced amniotic fluid both reflects reduced uterine placental sufficiency and predisposes to fetal compromise because of the likelihood of cord compression. Thick meconium is more likely to be aspirated. 95% of cases of MAS (Meconium Aspiration Syndrome) develops in the presence of thick meconium (K&B 1992). Thick meconium is therefore more likely to be associated with fetal distress.”
In some cases, the care provider may opt to do an amnioinfusion, a procedure that adds saline into the uterus to dilute the meconium in hopes of reducing the risk of meconium aspiration. While some care providers continue to support and use this technique, evidence has shown it may not be as successful as originally believed. “The New England Journal of Medicine (NEJM) found that amnioinfusion did not reduce the risk of moderate or severe meconium aspiration syndrome, perinatal death, or other major maternal or neonatal disorders in women who had thick meconium staining in the amniotic fluid (2).
What are the risks if there is meconium present in the amniotic fluid?
One concern is the baby will aspirate the meconium and it will be drawn into the baby’s lungs. If the baby did aspirate some of the meconium – which is called Meconium Aspiration Syndrome (MAS) – rest assured, most cases of MAS are not serious (3). Since the meconium is thick, MAS causes the baby to have difficulty breathing, inhibiting the baby’s airway and also irritating the lung tissue. The care provider will asses the health of the baby at birth and if it looks like the baby’s vitals signs are depressed, they will use suction to remove the amniotic fluid. Most babies with MAS improve within a few days or weeks, depending on the severity of the aspiration. Although a baby’s rapid breathing may continue for days after birth, there’s usually no severe permanent lung damage (4).
If your baby did not pass the meconium during labor, you can expect this sticky substance to make an appearance within the first few days of your baby’s life. Meconium is rather tar-like in that is it pretty challenging to rub off your newborn’s sensitive bottom. Try rubbing a little olive oil on your baby’s bottom to help with easy removal, and remember, when choosing the kind of oil to use, stay away from baby oil, which is petrolatum based and not good for your baby.