In MAS, which prenatal exposure is commonly associated with the condition?

• A. Postnatal exposure to air only.
• B. Prenatal preeclampsia.
• C. Prenatal meconium exposure.
• D. Postnatal dehydration.

Answer: (C)

Meconium in the amniotic fluid that the fetus inhales is the exposure most commonly linked to this condition. When a fetus experiences distress, it may pass meconium into the uterus, and inhalation of that meconium during or just after birth can block airways, trigger chemical pneumonitis, and disrupt surfactant function. This combination leads to the respiratory distress, hypoxemia, and imaging findings seen with meconium aspiration syndrome. Other options don’t directly explain the mechanism: postnatal air exposure, dehydration after birth, or maternal conditions like preeclampsia don’t inherently involve meconium exposure in utero.