[Creatine-kinase MM in the perinatal period].

One hundred eight newborns (gestational age 36 + 1.8 weeks and birth weight 2860 +/- 240 g) had muscle type Creatine-Kinase activity (CK-MM) assayed immediately after birth (CK-I) and serially at 6-10 h (CK-II), 20-30 h (CK-III) and 40-60 h (CK-IV) of age. Using statistical Regression analysis, CK-MM levels were correlated to four perinatal parameters: gestational age, birth weight, neonatal acidosis (pH less than 7.15), mode of delivery (vaginal/cesarean section). It was observed that CK-MM activity was dependent on gestational age and correlated to the mode of delivery at time III (600 U/l) and IV (400 U/l) comparing the mean serum values of 156 + 44 U/l observed in atraumatic delivery (p less than or equal to 0.05). Our results demonstrate markedly higher levels of CK-MM following vaginal delivery especially if complicated by forceps, vacuum and breech presentation, suggesting that birth trauma may be responsible for this phenomenon.