Objective
The purpose of this study was to determine whether there is a relationship between the frequency of meconium-stained amniotic fluid (MSAF) and the duration of labor in term singleton gestation.
Methods
The clinical characteristics of women who delivered term singleton live newborns between 2001 and 2006 were examined. The cases involving neonates with major congenital anomalies were excluded.
Results
(1) The frequency of MSAF in term pregnancies was 18.4% (806/4376); (2) MSAF was found in only 2.8% (28/1008) of women who delivered by elective cesarean, but in 23.1% (778/3368) of women who delivered after the onset of labor (p<0.001); (3) The longer the duration of labor (first stage, second stage, or total), the higher the frequency of MSAF (p<0.001 for each); this remained significant after adjusting for other confounding variables such as parity, duration of rupture of membranes, gestational age at delivery, and mode of delivery (p<0.001 for each).
Conclusion
MSAF was found in only 2.8% (28/1008) of women who delivered before the onset of labor, but in 23.1% (778/3368) of women who delivered after the onset of labor. The longer the duration of labor, the higher the risk of MSAF in term singleton gestation.