[Neonatal diseases with onset during fetal life. Clinical and etiopathogenetic considerations].

A modern definition is given of the perinatal period. The boundary between embryonal and foetal life is drawn to enable diseases than occur solely during the foetal period to be distinguished. Placental physiology, exchanges between mother and foetus and the general pathology of the foetus, with particular regard to immunological phenomena, are examined. An account is given of the carriage by the placenta of substances foreign to the body, the transplacental passage of drugs, and the permeability of the placenta to micro-organism. The several factors involved in this process are discussed. The effect of various micro-organisms on the foetus is illustrated. Modern views concerning the immunological position of the foetus are expounded and various situations where the foetus is at risk with respect to infection of the mother are considered.