Generated by electrical activity from depolarization and repolarization of billions of smooth muscle myometrial cells.
Monitoring of such contractions by tocodynamometry during induction or augmentation of labor.
Induction or augmentation is required in 20% of all deliveries and internal or external monitoring can quantify the frequency, duration, and magnitude of uterine activity.
In a randomized trial to assess whether the use of an intrauterine pressure catheter during labor leads to better outcome than those associated with the use of external monitoring: operative delivery was 31.3% in the internal tocodynamaometry group and 29.6% in the external monitoring and the rate of adverse neonatal outcomes was 14.3% with internal monitoring and 15% with external monitoring (Bakker JJ).