Pilot Study to Evaluate a Prototype Electronic Uterine Inhibitor to Prevent Preterm Contractions

Electrical intervention (EI) is bipolar, constant-current (1-20 mA), square-wave pulses in 20% duty cycles. Women in preterm labor have an electrode placed vaginally; tocodynamometric contraction timing and fetal heart rate are monitored continuously. Successive 20-minute periods include pre-control period (C1); the EI period, in which a 10-second current burst is delivered at expected contraction times; and a post-EI control period (C2).