The lecithin/sphingomyelin (L/S) ratio in twin pregnancies

The lecithin/sphingomyelin (L/S) ratio has been estimated in the amniotic fluid from 20 patients with a twin pregnancy. The values in each pair of amniotic fluids were closely related. If amniotic fluid from one sac only is available, it is suggested that a ratio of 2-5:1 is taken as the lower limit to predict the functional lung maturity of both twins.