Effect of prostaglandin E2 on myometrial electrical activity in women undergoing induction of labor

To investigate the effect of prostaglandin E2 (PGE2) on electrical uterine activity using a novel uterine muscle electromyography device in patients undergoing induction of labor.

Electrical uterine myography (EUM) was prospectively measured using a noninvasive nine channels recorder in 31 women undergoing induction of labor with vaginal PGE2 tablets. Women were monitored before and up to 12 hours after vaginal PGE2 application. EUM index was defined as mean electrical activity of the uterine muscle over a period of 10 minutes measured in units of microjoule (µJ, µWs).

The EUM index was not increased significantly during the first 2 hours following PGE2 application (overall increase of 5.3 ± 60.1%, p = 0.7). Peak EUM activity was observed during 2 to 8 hours following PGE2 application, which represented a statistically significant increase compared with the EUM index before PGE2 application (3.3 ± 0.5 µJ vs. 2.5 ± 0.95 µJ, p = 0.01), and with the EUM index 0 to 2 hours following PGE2 application (3.3 ± 0.5 µJ vs. 2.3 ± 0.9 µJ, p = 0.004).

The data suggests that in women undergoing labor induction with PGE2, uterine activity peaks 2 to 8 hours following PGE2 application. This information may provide more insight into the mechanism of PGE2 action.