Chronic villitis of unknown aetiology and intrauterine growth-retarded infants of normal and low ponderal index.

Placentae from 211 term pregnancies were studied. The placentae were divided into three groups: group I, 57 placentae from neonates with birthweight over the 25th centile of the normal birthweight curve; group II, 49 placentae from neonates whose birthweight fell between the 10th and 25th centiles of this curve, and group III, 105 placentae from neonates whose birthweights were below the 10th centile of the curve. Each of the studied groups were divided into two subgroups, one comprising those infants with a normal Ponderal Index (PI) and the other comprising those with a low PI. A higher incidence of chronic villitis and of inflamed villi was observed as the average birthweight decreased in cases with normal PI as well as in cases with low PI, the highest incidence being found in placentae from infants with harmonic intrauterine growth retardation (normal PI). The same was observed with respect to the presence of maternal vascular lesions in all groups studied. It is suggested that an infant's birthweight and crown-heel length may be affected as a consequence of the extension and severity of the placental lesions and the timing of their appearance in gestation.