Serum lactic acid dehydrogenase and isoenzymes during pregnancy and labor.

Total serum lactic acid dehydrogenase activity (LDH) and the levels of LDH isoenzymes were investigated in 14 women during early pregnancy (8--16th week), in 28 women during late pregnancy (29--37th week), in 73 at term (38--42nd week) and in 27 during labor (38--42nd week). LDH activity was found to be elevated in severe pre-eclampsia and in chronic hypertensive women during pregnancy as well as during normal and dysfunctional labor. No change was established in total serum LDH during normal pregnancy. LDH 1 was increased during late pregnancy and at term. In severe pre-eclampsia and during normal labor it was decreased. LDH 2 was also decreased in severe pre-eclampsia and during dysfunctional labor. LDH 3 was decreased during late pregnancy but increased in severe pre-eclampsia. No change was observed in LDH 4 during pregnancy, or in labor. LDH 5 was increased in normal and dysfunctional labor.