To investigate the influence of meconium in AF, 10 mL of non-meconium-stained AF was mixed with 2, 4, or 6 mL of meconium. The concentration of lactate in AF was then analysed at regular intervals. The analysed levels of lactate were approximately the same throughout the experiment . Similar tests were performed with a mixture of blood and amniotic fluid. The test showed that the concentration of lactate in AF could be affected by a high concentration of blood. Amniotic fluid samples tinged with a high degree of blood (≥ 10%) have therefore been removed from the analysis.