Fetal lactic dehydrogenase variation in normal pregnancy and in cases of severe intra-uterine growth restriction

Physiological and pathological fetal levels of lactic dehydrogenase (LDH), including its five different iso-enzymes are still poorly known. Our object ives were to compare total LDH levels and its five iso-enzymes between a co ntrol group of healthy fetuses and a group of fetuses with severe intra-ute rine growth restriction (IUGR), and to determine the biochemical associatio ns and the prognostic value of elevated LDH activity in fetuses with IUGR. Total LDH levels, haematologic values and liver enzyme activities were meas ured in 108 healthy fetuses from 17 to 37 weeks of gestation and in 44 fetu ses with severe IUGR. Total fetal LDH in plasma from the healthy fetuses we re constant throughout pregnancy (mean (SD) = 305.09 (46.97)). Total LDH va lues in plasma significantly increased in cases of IUGR (p = 0.003), and th e degree of increase was significantly correlated with fetal erythroblastos is (n = 44, r = 0.80, p <0.001). LDH 5 significantly decreased in the IUGR group (p = 0.03). Total LDH values strictly above 400 IU/l (a value equal t o the mean + 2 SD in the healthy fetus group) were found to be significantl y associated with thrombocytopenia (p <0.001), erythroblastosis (p = 0.008) and an increase in AST value (p = 0.03). These results suggest that the fetal LDH value in plasma is a useful biolog ical marker for severe chronic distress. Copyright (C) 1999 John Wiley & So ns, Ltd.