What is the main characteristic of meconium?

Meconium is primarily characterized by being a thick, tarry substance. This is due to its composition, which includes a mixture of amniotic fluid, bile, and cellular debris from within the fetus, such as shed skin cells and mucus. This dense consistency, often described as dark green or black in color, reflects the accumulation of substances that the fetus ingests during gestation and its inability to pass any stool prior to birth.

In contrast, other options do not accurately represent the nature of meconium. For instance, while bile may play a role in digestion, it is not the primary component of meconium; rather, it contributes to its color. A clear fluid would imply a different substance altogether, such as amniotic fluid, which is not indicative of meconium. Lastly, a mucus-like substance may describe certain bodily secretions but does not encapsulate the specific, thick, and tarry characteristics that define meconium. Understanding these distinctions is essential for recognizing the relevance of meconium in neonatal assessments, especially in the context of potential complications like meconium aspiration syndrome.