Meconium: A 1990s perspective on an old obstetric hazard

Objective: To quantify the current perinatal consequences associated with intrapartum detection of meconium in the amniotic fluid (AF). Methods: We compared retrospectively the outcomes in 8136 term singleton cephalic pregnancies with meconium and 34,573 similar pregnancies with clear AF. Results: Virtually all measures of adverse fetal-neonatal outcomes were significantly increased with meconium. For example, perinatal mortality increased from 0.3 per 1000 births with clear AF to 1.5 deaths per 1000 with meconium (P < .001). Most of these deaths resulted from meconium aspiration. Other unwanted outcomes also increased; eg, severe fetal acidemia at birth (umbilical artery blood pH 7.00 or less) increased from three per 1000 to seven per 1000 when meconium was diagnosed (P < .001). Delivery by cesarean also increased with meconium, from 7 to 14% (P < .001). Conclusion: Meconium in the AF is an obstetric hazard with small but significantly increased risks of adverse fetal-neonatal outcomes.