Association of elevated umbilical cord blood creatine kinase and myoglobin levels with the presence of cocaine metabolites in maternal urine.

Abstract

To determine whether an association exists between antenatal cocaine exposure and elevated levels of creatine kinase (CK) and myoglobin in umbilical cord blood collected upon delivery. 105 anonymous maternal urines with corresponding infant umbilical cords bloods. Maternal urines were screened for cocaine metabolites by the Syva EMIT assay, with positive specimens confirmed by gas chromatography/mass spectrometry. For all 8 positives, plus the first 47 of the negatives collected, matched infant cord blood specimens were analyzed for myoglobin by radioimmunoassay and CK by kinetic enzyme activity assay. Cord bloods matched to the remaining 50 cocaine-negative urines were not analyzed. A two-tailed Mann-Whitney test was used to evaluate the significance of differences in CK and myoglobin levels between the two groups. CK levels were evaluated twofold in the cocaine-positive group as compared to the cocaine negative group (mean 383 +/- 260 vs. 189 +/- 68 IU/L, p = 0.005). Myoglobin levels were twofold higher in the cocaine-positive group compared to the cocaine negative group (mean 55.9 +/- 37.1 vs. 33.3 +/- 26.8 ng/mL, p = 0.077). Antenatal cocaine exposure is associated with elevated cord blood CK, and possibly with elevated cord blood myoglobin. Additional studies, using larger study populations and more sensitive methods of detecting antenatal cocaine exposure, along with detailed follow-up examination of infants, are indicated.