Lactate dehydrogenase (LDH), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) concentrations and platelet counts were measured in 26 normal pregnant women and 51 preeclamptic women. In the normal-pregnancy group, no significant changes were found in the results of these tests. In the preeclampsia group, ALT and AST concentrations were not significantly higher than those in normal pregnancy, but the LDH concentrations increased and the platelet counts decreased significantly through the pregnancy. The increases in LDH did not correlate with changes in ALT or AST. Preeclamptic women with small-for-gestational-age (SGA) infants had significantly higher LDH concentrations than those in the appropriate-for-gestational-age (AGA) group, but ALT and AST concentrations did not increase significantly. As reasons for the LDH increase in our subjects, liver damage was excluded and more active glycolysis in addition to severe cell damage due to chronic anoxemia were inferred. It is suggested that an increase in LDH is predictive of SGA infants in preeclamptic pregnancy, especially in those with normal liver function.