We sought (1) to identify risk factors for meconium aspiration syndrome (MAS) among infants born to women whose labors were complicated by thick-consistency meconium-stained amniotic fluid (MSAF), and (2) to determine whether risk factors and infant prognosis differ according to the time of onset of respiratory distress. We performed a secondary analysis of a multicenter randomized trial of amnioinfusion (AI) for the prevention of MAS among women with thick-consistency MSAF. MAS was defined as onset of respiratory distress requiring oxygen supplementation within the first 4 hours of life. Patients with respiratory symptoms with onset at >or=4 hours were treated as a separate outcome category, "late-onset respiratory distress." We developed peripartum and intrapartum regression models to identify the risk of MAS and its subgroups. A tracing with marked abnormalities was a significant risk factor for moderate/severe MAS, but not for mild MAS or for late-onset respiratory distress. Meconium below the vocal cords and need for resuscitation immediately after birth were risk factors for mild and moderate/severe MAS as well as for late-onset respiratory distress. The risk of nonrespiratory comorbidities varied directly according to the severity of the respiratory distress. Late-onset respiratory distress shares several risk factors with MAS, as defined by Rossi et al. The two conditions may represent different manifestations of the same disease process.
Thieme Medical Publishers.