Calponin levels in term laboring women

OBJECTIVE: Calponin, a specific smooth muscle contraction regulatory troponin-like protein, is present in large quantities in uterine smooth muscle. Serum troponin levels rise in acute myocardial infarction, and creatine phosphokinase levels rise at high physical activity, both due to destruction of cardiac and striated muscle fibers. We hypothesize that the active labor process may cause uterine smooth muscle cell damage, which may result in rising maternal serum calponin levels. This was a preliminary study, searching for a new biomarker for preterm labor. METHODS: The study group included laboring term primiparous women with a singleton fetus. The control group included similar demographic and pregnancy characteristics pregnant women not in labor. Maternal serum levels of calponin basic isoform were measured evaluated and compared in both groups. RESULTS: Study group included 100 pregnant women. Calponin serum levels were higher in the active labor (794 ± 974 ng/mL) than in the group not in labor (591 ± 587 ng/mL), although it did not reach statistical significance. Gender and neonatal weight were similar in the two study groups. CONCLUSIONS: Calponin serum levels showed moderate elevation during active labor, compared to the levels in a cohort of pregnant comparable women at the same gestational weeks but not in labor.