Meconium passage: a new classification for risk assessment during labor.

The significance of MSAL as a sign of fetal distress is controversial. To better assess this condition, we present a classification of MSAL based on the timing and quantity of meconium passed and divided into early light, early heavy, and late passage of MSAL. By means of this classification with a problem-oriented risk assessment system, 2,933 pregnancies were prospectively evaluated during labor. The incidence of meconium passage was 22 per cent, of which early light constituted 53.6 per cent, early heavy 25.2 per cent, and late passage 21.2 per cent. Early heavy MSAL is associated with increased fetal and neonatal morbidity and death, and with a number of antecedent obstetric problems. Late passage of MSAL encountered no perinatal losses, but is associated with increased neonatal morbidity occurring late in labor. Early light MSAL, constituting over half of all our meconium group of patients, is not associated with any increased intrapartum or neonatal morbidity or death. This classification of MSAL is an effective tool for risk assessment during labor.