Final answer:
Respiratory distress in a 12-hour-old newborn requires immediate intervention and may indicate serious complications such as meconium aspiration, which can cause pulmonary inflammation, hypertension, and increase the risk of pneumonia.
Step-by-step explanation:
Among the manifestations listed for a 12-hour-old newborn, the one that requires immediate intervention is c. Respiratory distress. While frequent crying, passage of meconium stool, and sleeping for extended periods can be normal in newborns, respiratory distress is a sign of potentially serious complications. Aspiration of meconium, a tarry substance the newborn passes as the first stool, can result in labored breathing and serious conditions like pulmonary inflammation or hypertension. A newborn with respiratory distress could have inhaled meconium, leading to airway obstruction and alveolar collapse, making them vulnerable to further infections such as pneumonia. The obstetrician should promptly evaluate the newborn, and if meconium aspiration is suspected, blood gas tests, chest X-rays, and stethoscope examination are necessary to confirm and address the issue.