Influence of long-term beta-mimetic therapy on the lecithin content of amniotic fluid.

The lecithin content of 157 amniotic fluid samples taken from 60 patients who had been treated with Fenoterol over a long period of time (longer than 30 mg/daily per os for 14 days; intravenous infusion for longer than 7 days) was calculated thin-layer chromatographically according to Kynast and Saling. These lecithin levels were statistically compared with the levels in a control (Wilcoxon test). It emerged that the lecithin levels in the long-term beta-mimetic therapy group were significantly lower, i.e., from 33/0 to 39/6 (33/0-34/6, p less than 0.05; 35/0-39/6, p less than 0.01). The answer to the question how often levels occur in the long-term group which are below the as critical described level of 3 mg Lec/100 ml amniotic fluid appears to be clinically important. It is shown that values below the critical level from 33/0 to 39/6 are much more frequent in the long-term beta-mimetics therapy group than in the control group. There is no known explanation for this. It was concluded that the application of beta-mimetics in cases of long-term tocolysis should only be discontinued when the lecithin content of the amniotic fluid lies above the critical limit of 3 mg Lec/100 ml.