Meconium contamination of the neonatal middle ear

The neonatal middle ear and mastoid cavity are frequently contaminated by cells and hair of the amniotic fluid. This amniotic fluid cellular content provokes a foreign body inflammatory reaction that can persist for months. To evaluate whether clinical and postmortem findings might correlate with the amount of amniotic fluid cellular content in the middle ear, we compared temporal bones of nine patients born through meconium-contaminated amniotic fluid with those of 10 patients born through clear amniotic fluid. All patients were examined at less than 17 days postpartum and provided 37 temporal bones for histologic analysis. The volume of contaminant was quantified for each patient. The cases were arranged according to volume of contaminant in the middle ear and compared with clinical information and autopsy findings. Patients with larger volumes of contaminant in the middle ear were born through thick, meconium-stained amniotic fluid (1.9-38 mm3; average 9.3 mm3). Conversely, patients with lesser volumes of contaminant in the middle ear were born through unstained amniotic fluid (none to 3.2 mm3; average 0.9 mm3). We speculate that patients born through thick, meconium-stained amniotic fluid may be at greater risk of sequelae such as otitis media from this foreign body inflammatory reaction in the middle ear and mastoid cavity.