Changes in amniotic fluid phospholipids on treatment with glucocorticoids to prevent respiratory distress syndrome

Amniotic fluid was obtained by transabdominal amniocentesis in 51 women in the 29th-36th week of pregnancy. The lecithin/sphingomyelin ratio was determined. In 28 patients,the ratio was less than 2.2. Beta-methasone was given for three days to 14 of them; the rest served as controls. On the fourth day, a second amniocentesis was performed on all patients. The lecithin/sphingomyelin ratio rose to a value greater than 2.2 in 4 of the patients in the betamethasone-treated group and in one of the controls. The percentage of palmitic acid in the lecithin increased concomitantly with increasing lecithin/sphingomyelin ratio. These results suggest that glucocorticoid induced acceleration of fetal pulmonary maturation may be reflected in the amniotic fluid as changes in its phospholipid composition. The lecithin/sphingomyelin ratio was found to be greater than 2.2 in 23 patients at the first amniocentesis. In such cases treatment with glucocorticoids can be avoided.