[Amniotic fluid concentrations of thyroxine, reverse triiodothyronine and lecithins].

In the present study we tried to find out relationships between lung maturation-assessable by aid of lecithin concentrations in amniotic fluid-and fetal thyreoid gland function. In 256 pregnant women amniocentesis was done after 31/0 weeks of gestation, and concentrations of thyroxin, of reverse triiodothyronine and lecithins were measured. While thyroxin and lecithin concentrations proved not to be correlated, the rT3 and lecithin concentrations showed significant correlation (2 p less than 0.001). The curves measured were interpreted as signs of maturity of various organs (lung, thyreoid gland). We found out, that clinical value of measuring thyreoid gland hormones in relation to diagnosis of fetal maturation is of less importance.