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- Development and evaluation of an algoritm for computer analysis of maternal heart rate during laborPublication . Pinto, Paula; Bernardes, João; Costa-Santos, Cristina; Amorim-Costa, CéliaBackground Maternal heart rate (MHR) recordings are morphologically similar and sometimes coincident with fetal heart rate (FHR) recordings and may be useful for maternal–fetal monitoring if appropriately interpreted. However, similarly to FHR, visual interpretation of MHR features may be poorly reproducible. Methods : A computer algorithm for on-line MHR analysis was developed based on a previously existing version for FHR analysis. Inter-observer and computer-observer agreement and reliability were assessed in 40 one-hour recordings obtained from 20 women during the last 2 h of labor. Agreement and reliability were evaluated for the detection of basal MHR, long-term variability (LTV), accelerations and decelerations, using proportions of agreement (PA) and Kappa statistic (K), with 95% confidence intervals (95% CI). Changes in MHR characteristics between the first and the second hour of the tracings were also evaluated. Results There was a statistically significant inter-observer and computer-observer agreement and reliability in estimation of basal MHR, accelerations, decelerations and LTV, with PA values ranging from 0.72 (95% CI: 0.62–0.79) to 1.00 (95% CI: 0.99 1.00), and K values ranging from 0.44 (95% CI: 0.28–0.60) to 0.89 (95% CI: 0.82–0.96). Therover, basal MHR, number of accelerations and LTV were significantly higher in the last hour of labor, when compared to the initial hour. Discussion The developed algorithm for on-line computer analysis of MHR recordings provided good to excellent computer-observer agreement and reliability. Moreover, it allowed an objective detection of MHR changes associated with labor progression, providing more information about the interpretation of maternal–fetal monitoring during labor.
- Computer analysis of maternal–fetal heart rate recordings during labor in relation with maternal–fetal attachment and prediction of newborn acidemiaPublication . Pinto, Paula; Costa-Santos, Cristina; Ayres-de-Campos, DiogoAbstract Objective: To assess combined maternal (MHR) and fetal heart rate (FHR) recordings during labor, in relation with maternal–fetal attachment and prediction of newborn acidemia.Study design: Fifty-nine simultaneous MHR and FHR recordings were acquired in the final minutes of labor. Computer analysis followed the FIGO guidelines with estimation of MHR and FHR baselines, accelerations, decelerations, short- (STV) and long-term variabilities. MHR and FHR characteristics, their differences and correlations were assessed in relation to labor progression and to newborn umbilical artery blood (UAB) pH lower than 7.15 and 7.20. To assess prediction of acidemia, areas under ROC curves (auROC) were calculated.Results: Progression of labor was associated with a significant increase in MHR accelerations and FHR decelerations both in the non-acidemic and acidemic fetuses (p50.01). At the same time there was an increase in MHR–FHR correlations and differences in accelerations and decelerations in acidemic fetuses. The auROC ranged between 0.50 for FHR accelerations and 0.77 for MHR baseline plus FHR STV. Conclusions: MHR and FHR respond differently during labor with signs of increased maternal– fetal attachment during labor progression in acidemic fetuses. Combined MHR–FHR analysis may help to improve prediction of newborn acidemia compared with FHR analysis alone.
- External Uterine Contractions Signal AnalysisPublication . Gonçalves, H; Pinto, Paula; Ayres-de-Campos, D; Bernardes, JoãoLabor dystocia is a major cause of operative delivery, which is associated with ncreased risks for both mother and fetus. We assessed linear and non-linear dynamics of external uterine contraction signals, in relation to labor progression and dystocia. Linear time domain, spectral and entropy methods were used to analyze external uterine contraction recordings obtained during the last two hours of labor, in 28 cases with normal and 27 cases with operative deliveries (forceps, vacuum or caesarean). Progression of labor was associated with a statistically significant increase in most linear time domain and spectral indices, both in normal and operative deliveries, whereas most entropy indices increased in normal deliveries, but did not change in operative deliveries. On the other hand, when compared with normal births, operative deliveries were associated with significantly increased entropy indices before the last hour of labor and significantly decreased (a probably associated) sympatho-vagal balance in the last hour of labor. Linear and non-linear analysis of external uterine contraction recordings may provide useful physiopathological and clinical information on the progression of labor and the diagnosis of dystocia.