Final answer:
The symptom of an infant with meconium aspiration is rapid breathing, which results from the inhalation of meconium causing obstruction and distress in the newborn's airways.
Step-by-step explanation:
The symptom of an infant with meconium aspiration is A. Rapid breathing. When a fetus inhales meconium-stained amniotic fluid, it can lead to a condition known as meconium aspiration syndrome (MAS), which is characterized by difficulty breathing.
This happens because meconium can obstruct the newborn's airways, cause alveolar collapse, interfere with surfactant function critical for lung operation, or induce pulmonary inflammation and hypertension. All of these complications from inhaled meconium can make it difficult for a newborn to breathe efficiently, resulting in rapid, labored breathing or other respiratory distress symptoms, such as a barrel-shaped chest or a low Apgar score.
During delivery, if the amniotic fluid is greenish or yellowish, it indicates that the fetus has passed meconium, often signaling fetal distress such as hypoxia. To minimize the risk of MAS, an obstetrician will often aspirate the infant's airways right after the head is delivered.
This preventive step is vital because meconium aspiration can increase the newborn's vulnerability to pulmonary infections like pneumonia, providing another reason why rapid breathing is observed as a critical symptom of this condition.