Biomarkers of Uterine Muscle Physiology

Elevated amniotic fluid lactate (AFL) and uterine electromyography (EMG) mathematically transformed to calculated the power density spectrum median frequency have been found separately to be associated with labor dystocia and cesarean birth. Similarly, recent research indicates that the cytokine IL-6 may play a critical role in labor onset and potentially labor progression. All three are hypothesized to reflect that uterine fatigue plays a role in the pathophysiology of labor dystocia for some women. This study aims to characterize the relationship between these three measures to better understand the role of uterine fatigue in labor dystocia and triangulate biomarkers of fatigue that may lead to a better understanding of labor dystocia phenotypes. In addition to the primary measures, comparison measures will be collected. For AFL comparison, venous whole blood lactate and capillary lactate will be collected and measured using both a point-of-care lactate meter (Stat Strip Lactate Meter, Nova Biomedical) and a table-top blood gas analyzer (Nova Prime). For EMG comparison, routine contraction monitoring data will be collected and compared to the EMG signal. IL-6 will be measured both in blood and amniotic fluid using a novel microsampling protocol. Three visual analog scales on women's experiences of fatigue, anxiety, and pain will also be administered. Additional data will be collected from the medical record to perform exploratory and hypothesis generating analysis.