Fig. 1. (Top ) Changes in maternal sufentanil plasma concentrations (pg/ml) after 25 μg intraamniotic sufentanil over time; n = 7;superimposed thick line = median; *P < 0.05 versus 0 min. (Bottom ) Changes of maternal sufentanil plasma concentrations (pg/ml) after 50 μg intraamniotic sufentanil over time; n = 7;superimposed thick line = median; *P < 0.05 versus 0 min; #P < 0.05 versus fetus 50 μg intraamniotically.