Abstract
Uterine and abdominal muscle contractility are important in the control of labor and birth. The diagnosis of labor onset has been described as one of the most crucial and important judgments for effective management and successful outcome of pregnancy. Regular uterine contractions and cervical dilatation are the most common indicators of the onset and progress of labor. Better identification of onset of labor could contribute to the diagnosis of true labor. This could potentially improve the assessment of abnormalities, lead to enhanced quality of care, more accurate identification of risk groups, better counseling of patients, individualized management, and timely interventions. Electrical activity of uterine and abdominal muscles regulates contractility; therefore, measurement of electrical activity is key to understanding the stages of labor. Electrical activity of muscles can be measured by electromyography (EMG), which for recordings of uterine activity is also often referred to as electrohystography (EHG). In this brief review we summarize recent EMG studies of uterine and abdominal electrical activity, their relationship to cervical dilation and describe the importance of these events to the diagnosis for the onset and progress of labor.