The Significance of ‘Non-Significant’ Meconium Stained Amniotic Fluid (MSAF): Colour versus Contents

The presence of ‘thin’ or ‘non-significant’ meconium stained amniotic fluid (MSAF) is currently being considered by some intrapartum guidelines as ‘low risk’, requiring only an intermittent auscultation and not continuous electronic fetal heart rate monitoring using the cardiotocograph (CTG). Clinicians not only must exclude ‘non-physiological’ causes of MSAF but consider the potential effect of MSAF on fetal wellbeing, irrespective of whether the passage was secondary to a normal physiological process or due to an underlying pathology. Management decisions should be made based on the parity, rate of progress of labour, cervical dilatation at diagnosis, and observed CTG changes and the risk factors such as multiple pregnancy and intra-uterine growth restriction. Presence of any meconium within the amniotic fluid should be considered as an important intrapartum risk factor. The thin meconium may be ‘non-significant’ on visual inspection, but it is very significant from the point of view of a fetus, who is covered with toxic materials within the surrounding amniotic fluid.