Total creatine kinase (CK) and CK-B activity in maternal blood and cord-blood samples after vaginal and cesarean births.

We studied variations in the activity of total creatine kinase (CK; EC 2.7.3.2) and of CK-B in maternal and cord-blood samples, comparing data obtained for vaginal and cesarean births. CK-B activity was determined with an immunoinhibition assay. In all cases, there was a significant postpartum increase in total CK and in CK-B activity in maternal sera, whereas cord-blood samples showed no significant differences between activities in arterial and venous blood for either vaginal or cesarean births. Statistically significant differences were found in CK-B activity, but not in total CK, between cord-blood samples from vaginal births and those from cesareans.