[en] The compartment models of transplacental transfer of tritiated water injected into pregnant females, to foetuses and of lacteal transfer of tritiated water injected into nursing females, to sackling newborn mice were presented, respectively. There are many assumptions in the models and they do not fit the experimental data well. However, some of the differences between the models and experimental data can be qualitatively explained by physiological reasoning. The changes in the kidney functions of pregnant women are also the important factors which have to be considered to analyze the dynamics. The present dynamics analyses with mice can contribute to the understanding of the dynamics of tritiated water in humans. (Namekawa, K.)