Meconium-stained amniotic fluid and meconium aspiration syndrome: a prospective study

Background: The incidence of meconium aspiration syndrome (MAS), associated perinatal factors, morbidity and deaths varies widely. This study aimed to assess the perinatal attributes and morbidity associated with MAS. Methods: Over a 2-year period, all neonates born through meconium-stained amniotic fluid (MSAF) were observed for respiratory distress (RD). Birth details, chest radiograph (CXR) and clinical course were documented. Neonates with consistent CXR findings whose RD could not otherwise be explained were defined as MAS. Results: Of 409 neonates born through MSAF, meconium was thick in 196 (47.9%). Fifty-five (13.4%) had RD and 45 (11.3%) were consistent with MAS. Six (1.5%) neonates died. Mean (SD) birthweight and gestation of MAS infants were 2721.9 (510.2) g and 38.67 (1.09) weeks, respectively. About one-third were of low birthweight and 28 were born by caesarean section. On univariate analysis, caesarean delivery, meconium in the trachea and thick meconium were the significant perinatal factors for the development of MAS. On multiple regression analysis, thick meconium was the only independent factor for MAS (OR 7.08, 95% CI 3.08-16.27, p<0.001). An Apgar score of <= 6 and blood gas abnormalities were found in 44.4% and 48.9%, respectively. Air leak syndrome was observed in 12 (26.7%), persistent pulmonary hypertension in seven and severe asphyxia and late sepsis in two each. Thirteen (28.9%) required mechanical ventilation and six (13.3%) died. Conclusion: MAS occurred in 11.3% of neonates born through MSAF. Thick meconium was found to be an important causative factor. Nearly one-third of infants with MAS required mechanical ventilation and 13.3%, died.