Total estrogens (E/day), pregnanediol (P/day) in diurnal urine, and thermostable alkaline phosphatase (APt) in blood serum were investigated. Simultaneously, amnioscope examinations were carried out during pregnancy and the beginning of labour. A retrospective assessment of placental test values with respect to the state of newborns was also made. The usefulness of these tests in the diagnosis of a fetus at risk in multiple pregnancies appears to be limited.