Determination of L-lactate: NAD+ - oxidoreductase (E.C.1.1.1.27) and its isoenzymes during pregnancy

In the First Gynaecology and Maternity Clinic of the Faculty of Medicine, Charles University Prague, we investigated total serum LDH (L-lactate: NAD-oxidoreductase, E.C.1.1.1.27) activity and that of its 5 isoenzymes during physiological pregnancy. We divided our pregnancies, for practical purposes, into 3 groups. The first comprised women in the 10th-to 20th week of pregnancy, the second women in the 20th to 30th week and the third women in the 30th to 40th week. In each group we took blood dynamically at regular 14-day intervals from the same women, with the aim of assuring the maximum possible homogeneity of the tested material (blood) in correlation to time. We found that, during physiological pregnancy, neither the total LDH activity level, nor that of its five fractions, exceeded the norm determined for the Czechoslovak population. The activities fluctuated typically during pregnancy, however, within the framework of the norm. Some agreement was found between changes in LDH activity and changes in the chorionic gonadotrophin level.