Maternal cardiac troponin I levels during normal labor and delivery

OBJECTIVE: Diagnosis of myocardial infarction in pregnant women on the basi s of changes in biochemical markers is complicated by the release of some o f these markers from noncardiac tissue sources. We compared troponin I leve ls with those of other markers in normal pregnant women. STUDY DESIGN: In 51 healthy women at term in labor, cardiac troponin I, myo globin, creatine kinase, and creatine kinase MB levels were determined at a dmission, during the second stage of labor, and within 30 minutes, 12 hours , and 24 hours after delivery. RESULTS: Mean admission levels for all markers were below the upper limit o f normal. Mean concentrations of myoglobin, creatine kinase, and creatine k inase MB mass were increased nearly twofold within 30 minutes after deliver y. The highest level of troponin I (0.134 ng/mL) at all time points was bel ow the cutoff Value (0.15 ng/mL) for discriminating myocardial infarction. CONCLUSIONS: Because only troponin I levels remained undetectable during an d after delivery, it is potentially the most useful biochemical marker for monitoring pregnant women for myocardial injury.