Electrohysterographic characterization of the uterine myoelectrical response to labor induction drugs

Abstract

Labor induction is a common practice to promote uterine contractions and labor onset. Uterine electrohysterogram (EHG) has proved its suitability for characterizing the uterus electrophysiological condition in women with spontaneous labor. The aim of this study was to characterize and compare uterine myoelectrical activity during the first 4 h in response to labor induction drugs, Misoprostol (G1) and Dinoprostone (G2), by analyzing the differences between women who achieved active phase of labor and those who did not (successful and failed inductions). A set of temporal, spectral and complexity parameters were computed from the EHG-bursts. As for successful inductions, statistical significant and sustained increases with respect to basal period were obtained for EHG amplitude, mean frequency, uterine activity index (UAI) and Teager, after 60' for the G1 group; duration, amplitude, number of contractions and UAI for the G2 group, after 120'. Moreover, Teager showed statistical significant and sustained differences between successful and failed inductions (1.43 ± 1.45 µVHz10 vs. 0.40 ± 0.26 µVHz10 after 240') for the G1 group, but not in the G2 group, probably due to the slower pharmacokinetics of this drug. These results revealed that EHG could be useful for successful induction prediction in the early stages of induction, especially when using Misoprostol.

Prediction of Labor Induction Success from the Uterine Electrohysterogram

“…The reliable prediction of whether an induction agent could trigger APL or not would help clinicians to reduce unnecessary waits and decide whether or not to perform a cesarean section. Benalcazar et al found a significantly different response between the EHG characteristics of patients that succeeded in achieving APL and those that did not [15,16]. In the present work, we performed APL predictor systems (Scenario 1) with different sets of features: obstetrical (PS1_ 1), EHG (PS1_2), and a combination of both (PS1_3).…”

“…In a previous work, to analyze the evolution of the EHG burst parameters in response to labor induction drugs, we first computed the median values of each parameter associated with the EHG bursts present in nonoverlapping intervals of 30 minutes [15,16]. Results showed that for successful inductions, statistically significant and sustained increases with respect to the basal period were obtained after 60 minutes and 120 minutes in patients induced with misoprostol and dinoprostone, respectively [15,16]. This is the reason why, in the present work, in order to use only the significant intervals for both drugs, for each parameter, we analyzed 5 intervals of 30 minutes (basal period-before drug administration: 120 ′ , 150 ′ , 180 ′ , and 210 ′ ), giving rise to a total of 21 × 5 = 105 EHG features.…”

“…Previous studies have shown that EHG signals can discriminate effective contractions associated with imminence of labor [11] or whether delivery will be term or preterm [12]. EHG records have also been used to characterize the uterine myoelectrical response to labor induction drugs [13][14][15][16]. Aviram et al found that uterine electrical activity significantly increases 2 hours after prostaglandin E2 (PGE2) vaginal application and up to 8 hours after PGE2 application [13].…”

“…Benalcazar-Parra et al also studied the differences between failed and successful (reaching the active phase of labor (APL)) inductions by comparing the evolution of different EHG parameters. They found different responses, mainly in amplitude and spectral parameters after 60 ′ -120 ′ from labor induction onset [15,16]. However, to date, no work has been done on predicting successful induction from EHG records, while EHG-based neural networks have been applied to the prediction of term and preterm labor [12,[17][18][19].…”

“…However, even if APL has been reached, various conditions may prevent vaginal delivery, such as labor arrest, pelvic-fetal disproportion, or loss of maternal-fetal well-being [22]. In the labor induction context and from the pharmacologic point of view, induction can be considered successful if drug action helps the patients achieve APL [15,16,23]. From the medical point of view, only vaginal deliveries are commonly considered successful [24,25].…”