[Sonographically detectable fetal epiphyseal centers as a criterion for maturity in comparison to L/S ratio]

In 62 pregnant women between the 31st and 39th week of gestation who underwent amniocentesis for determination of the lecithin: sphingomyelin ratio in the amniotic fluid, sonographical identification and measurement of epiphyseal centres around the foetal knee joint were performed. If an epiphyseal centre in the proximal area of the tibia and/or an epiphyseal centre of 6 mm or more in the distal area of the femur could be identified, this showed that a lecithin: sphingomyelin ratio greater than or equal to 2 was present. This noninvasive method of measurement of epiphyseal centres by ultrasound allows not only an exact determination of gestational week in late pregnancy, but also supplies particularly in cases of nondiabetic pregnancies, an indirect pointer to foetal maturity.