Serum levels of plasma-derived toxic protein components, the median weight molecules (MWM), have been assayed in 206 women with third-trimester pregnancy and in their newborns. Toxemia of various severity was present in 194 women and had developed in the presence of an extragenital disease in 84.2% (pyelonephritis, glomerulonephritis, essential hypertension, etc.). Concentrations of MWM were found to increase with deterioration of renal function and to correlate with severity of nephropathy. In every second pregnancy with toxemia, interventions included extracorporeal detoxication: ultraviolet-irradiated blood autotransfusion (UIBA) and hemosorption. The rates of intra- and postpartum complications or requirement for surgery were 1.5-2-fold lower in these patients, and their newborns has better neonatal progress. Perinatal mortality of these patients was two times as low as that in the rest of the population (31.9:1000 versus 62.6:1000). The use of UIBA is recommended for mild and moderate toxemia and in combination with hemosorption for severe nephropathy.