In umbilical vein blood samples collected in 137 fetuses between 19 and 31 weeks of gestation, cortisol (F), cortisone (E), 17-hydroxyprogesterone (17-OHP) and 11-deoxycortisol (S) were radioimmunoassayed after column chromatography on Sephadex LH-20 of plasma extracts. While F levels plateaued throughout the period considered those of E displayed an increasing pattern which appeared to be comparable with that of unbound F in pregnant women. The declining pattern of S and more particularly of 17-OHP would suggest an increasing utilization and metabolization of these F precursors by the maturing fetus. E was not correlated with either 17-OHP or S but showed a significant correlation with F. S and 17-OHP were correlated with each other and with F. The significance of these correlations was discussed according to the different origin of these steroids and to their metabolic relationships. The application of this method for the prenatal diagnosis of inborn errors of steroid biogenesis is suggested.

Prenatal diagnosis of congenital toxoplasmosis was attempted by means of fetal blood sampling at 20 - 24 weeks' gestation. It was possible to detect in fetal blood samples non-specific laboratory signs of fetal infection, specific antibodies of fetal origin (IgM), and parasitaemia by inoculation of the sample into mice. Amniotic-fluid samples were also inoculated into mice and parasites were often present when the fetus was infected. Ultrasound examination of the fetus was done repeatedly, mainly to detect any enlargement of the cerebral ventricles. Together the results of these examinations allowed a reliable diagnosis, which was confirmed by the presence of necrotic foci of toxoplasmic encephalitis in the fetus in every case. Only 1 case of congenital toxoplasmosis occurred among 209 cases with negative prenatal diagnoses.

In an attempt at prenatal diagnosis of fetal infection after primary rubella infection before 18 weeks of pregnancy fetal blood was taken by direct puncture under ultrasound guidance at 20-26 weeks of pregnancy from eighteen patients. Total IgM was assayed by radial immunodiffusion and rubella-specific IgM by IgM capture immunoassay. Rubella-specific IgM was detected in twelve of the eighteen fetuses. The parents decided whether to continue or terminate the pregnancy on the basis of the time of onset of maternal rubella. All six pregnancies in which rubella occurred before 12 weeks of gestation were terminated. Of the six with rubella after 12 weeks two were terminated. Among the six fetuses negative for rubella-specific IgM, five had no rubella-specific IgM at birth and no persistent IgG but one was found to be infected at birth; this false-negative diagnosis was due to sampling too early during pregnancy.