[Serum creatine kinase in normal newborns (author's transl)]

Serum creatine kinase activity (CK) in 82 normal newborns was found to be significantly higher the 2nd day than the values found in the cord blood and on the 5th day after birth. Higher values were observed when labor was induced by oxytocin stimulation and following breech delivery where they could reach a level up to 40 times normal. No definite relationship was noted between the enzyme level at 2 days of age and the duration of the various stages of delivery. We conclude that, because of the increased CK activity found in normal newborns, screening for Duchenne muscular dystrophy should hence be postponed at least 5 days after delivery.