Changing Obstetric Practices Associated With Decreasing Incidence of Meconium Aspiration Syndrome

Abstract

In Brief OBJECTIVE To describe changes in neonatal and obstetric practices that may have contributed to the decreasing incidence of meconium aspiration syndrome in our population during this time. METHODS We compared neonatal and obstetric characteristics of 61 infants diagnosed with meconium aspiration syndrome with 1365 infants born through moderate or thick meconium-stained amniotic fluid at more than 37 weeks' completed gestation. Data were prospectively collected, and all respiratory diagnoses were concurrently made. Three distinct birth year groups were analyzed based on changing obstetric practice paradigms. RESULTS Meconium aspiration syndrome decreased nearly four-fold from 1990–1992 to 1997–1998 (5.8% to 1.5% of meconium-stained infants more than 37 weeks;P < .003). The only change in neonatal characteristics was a 33% decrease in births more than 41 weeks with a reciprocal 33% increase in births 38–39 weeks during 1997–1998. Significant changes in obstetric practice included more frequent diagnosis of nonreassuring fetal heart rate patterns, greater use of amnioinfusion, and increased cesarean delivery rate in 1997–1998. By logistic regression analysis, the only consistent risk factor for meconium aspiration syndrome across all three epochs was the presence of tracheal meconium. CONCLUSION Reduction in post-term delivery was the most important factor in reducing meconium aspiration syndrome. Changes in obstetric practice policies aimed at reducing intrapartum fetal compromise were associated with four-fold lower rates of meconium aspiration syndrome over a 9-year period.