the breathing of meconium containing fluid by the baby at birth
Syndrome caused by sucking of thick meconium into the lungs, usually by term or post-term infants (often small for gestational age) either in utero or with first breath. The resultant small airway obstruction may produce respiratory distress, tachypnea, cyanosis, pneumothorax, and/or pneumomediastinum.
A baby which becomes distressed before delivery may pass meconium (the dark greenish material described above) while he or she is still in the womb. If the baby then inhales the fluid in which he or she is "floating" in the womb, the sticky material irritates and partially blocks the airways, causing breathing difficulties in around the time that the baby is born.