Fetal Body Burden of Chemicals and its Effect on Fetal Growth and Development

Abstract

In order to examine the effect of chemicals on fetal growth and development, a series of experiments was projected as follows. First, distribution of chemicals among Maternal-Placento-Fetal Units was determined. Then, whether there exist any relation between fetal body burden of chemicals and fetal growth and development or not, was examined.1. Arsenic in fetal tissues could be detected long enogh after oral administration of NaAs-PO₂, to effect later fetal stage directly. The more the dose of NaAsO2, increased, the lower weights of fetal bodies and the fewer number of ossification bodies of caudal vertebrae, which express an aspect of Intra Uterine Growth Retardation, were exhibited .2. Concentraion of lithium in fetal tissues rised quickly after the administration of lithium solution (400mg/kg of LiCI) orally and decreased exponentially soon after . Only in the case of group administered with 40 mEq/l LiCI solution ad libitum for ten days, Intra Uterine Growth Retardation could be observed.3. In spite of 0.25 and 0.5 mg/kg (as Cd) administration of CdCl₂ subcutaneously for 11 days once a day, concentration of Cd in tissues of fetuses was shown trace and negligible . But the group dosed with 0.5 mg/kg of Cd showed significant Intra Uterine Growth Retardation without fetal body burden of Cd. Intra Uterine Growth Retardation was observed commonly among several groups as an effect of chemicals throughout the results of experiments done with different chemicals. It can be said that Intra Uterine Growth Retardation can be used as an indicator for the assessment of the effects of chemicals. Of course, Intra Uterine Growth Retardation without fetal body burden of chemicals must be discussed in distinction from that with fetal body burden.