Célia Amorim-Costa

Complexity-loss in fetal heart rate dynamics during labor as a potential biomarker of acidemia☆

BACKGROUND Continuous fetal heart rate (FHR) monitoring remains central to intrapartum care. However, advances in signal analysis are needed to increase its accuracy in diagnosis of fetal hypoxia. AIMS To determine whether FHR complexity, an index of multiscale variability, is lower among fetuses born with low (≤7.05) versus higher pH values, and whether this measure can potentially be used to help discriminate the two groups. STUDY DESIGN Evaluation of a pre-existing database of sequentially acquired intrapartum FHR signals. SUBJECTS FHR tracings, obtained from a continuous scalp electrocardiogram during labor, were analyzed using the multiscale entropy (MSE) method in 148 singletons divided in two groups according to umbilical artery pH at birth: 141 fetuses with pH>7.05 and 7 with pH≤7.05. A complexity index derived from MSE analysis was calculated for each recording. RESULTS The complexity of FHR signals for the last two hours before delivery was significantly (p<0.004) higher for non-acidemic than for acidemic fetuses. The difference between the two groups remained significant (p<0.003) when FHR data from the last 30min before delivery were excluded. CONCLUSION Complexity of FHR signals, as measured by the MSE method, was significantly lower for acidemic than non-acidemic fetuses. These results are consistent with previous studies showing that decreased nonlinear complexity is a dynamical signature of disrupted physiologic control systems. This analytic approach may have discriminative value in FHR analysis.

Gender-specific reference charts for cardiotocographic parameters throughout normal pregnancy: a retrospective cross-sectional study of 9701 fetuses

OBJECTIVE To establish reference values for cardiotocographic (CTG) parameters from 24 to 41 weeks of gestation in normal pregnancies. STUDY DESIGN Retrospective cross-sectional study, using the first antepartum tracing of singleton fetuses with normal pregnancy outcomes (term birth, normal birthweight, normal umbilical artery pH and Apgar scores, no intensive care unit admission). Cases were consecutively selected from a hospital electronic patient record, and analyzed using the OmniviewSisPorto 3.7 system. Variables were compared between male and female fetuses, by gestational age, and percentile curves were constructed. RESULTS A total of 9701 tracings (corresponding to 9701 fetuses) were analyzed. All CTG parameters changed significantly throughout gestation in both genders, with a decrease in baseline and decelerations, and an increase in average long-term variability (LTV), average short-term variability (STV), accelerations and uterine contractions. The mean baseline value decreased 9bpm, and its range almost doubled from 24 to 40 weeks. Until 30 weeks the lower percentiles for average LTV were below 5bpm, and the minimum value for average STV was never below 1bpm. The proportion of tracings without accelerations decreased from 30.1% at 24-25 weeks to 0.5% at 39 weeks. The median number of decelerations was practically zero for all gestational ages. All CTG variables, except decelerations and uterine contractions, showed statistically significant gender differences: baseline was consistently higher in females, while average LTV and average STV tended to be lower in females throughout most of pregnancy. Separate percentile curves were constructed for male and female fetuses. CONCLUSION This study provides reference values for CTG parameters throughout pregnancy, derived from the largest dataset of healthy fetuses published to date. For the first time, gender differences were clearly demonstrated in fetal life, and percentile curves constructed separately for male and female fetuses.

Uterine compression sutures for postpartum hemorrhage: is routine postoperative cavity evaluation needed?

Postpartum hemorrhage due to uterine atony continues to be one of the major causes of maternal morbidity and mortality. Several uterine compression suture techniques have been described and are increasingly being used worldwide as a conservative approach. However, little is known about the long‐term effects on the uterine cavity, as well as fertility and pregnancy outcomes. We reviewed the reported complications and uterine findings after the use of compression sutures, both in examinations to evaluate the cavity (hysteroscopy, hysterosalpingography or sonohysterography) and at cesarean section, in order to assess the possible usefulness of routine postoperative cavity evaluation. Overall, the use of uterine compression sutures is effective and safe; however, some severe and potentially life‐threatening complications have been reported and could possibly have been prevented if uterine cavity evaluation had been performed. Routine follow‐up, both by hysteroscopy and an imaging technique, seems worthwhile.

Development and evaluation of an algorithm for computer analysis of maternal heart rate during labor

BACKGROUND 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 2h 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). Moreover, 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.

Longitudinal evaluation of computerized cardiotocographic parameters throughout pregnancy in normal fetuses: a prospective cohort study.

The longitudinal cardiotocographic (CTG) changes throughout pregnancy in normal fetuses have never been fully described. We aimed at characterizing the evolution of CTG parameters in healthy fetuses, from 24 to 41 weeks of gestation.

Audit of a fetal central monitoring station in a clinical setting.

Abstract Objective. To conduct an audit of the Omniview-SisPorto® central monitoring station (CMS) and determine the effect of the measures undertaken to correct identified problems. Methods. All cardiotocograms (CTGs) recorded in randomly selected days of 2006 and 2009, both in the outpatient clinic and labor ward, were reviewed to assess the following parameters: tracing identification, duration, signal quality, signal loss, acquisition method, and time elapsed between tracing-end and birth. A random sample of cases was compared with original paper recordings and 25% of CTGs were re-retrieved for comparison with first retrieval. Results. Antepartum tracings were identified in 92% of cases. Mean signal quality rose from 96.4% in 2006 to 97.1% in 2009 (p = 0.009). Mean signal loss fell from 7.4% to 5.8% (p = 0.012). Intrapartum CTGs were identified in 44% of cases in 2006 and in 69% in 2009 (p < 0.001). Mean interval between tracing-end and birth decreased from 12.0 to 8.4 min (p < 0.001). Coincidence of variables in tracings retrieved twice increased between 2006 and 2009. All retrieved tracings matched the original paper recordings. Several technical problems identified in 2006 were not found in 2009. Conclusions. The Omniview-SisPorto® system showed reliable recording, storage, and retrieval of CTGs. Auditing of fetal CMSs allows improvement of their performance and use.

Evolution of linear and nonlinear fetal heart rate indices throughout pregnancy in appropriate, small for gestational age and preterm fetuses: A cohort study

BACKGROUND AND OBJECTIVES To assess the evolution of linear and nonlinear fetal heart rate (FHR) analysis throughout pregnancy in appropriate (AGA), small for gestational age (SGA) and preterm (PTB) fetuses. METHODS A prospective cohort study was carried out in 171 singleton pregnancies divided in three groups: AGA (n = 147), SGA (n = 13) fetuses and spontaneous PTB (n = 11). FHR was recorded with an external sensor from the 24th to the 40th week of gestation. Linear time- and frequency-domain and nonlinear FHR indices were computed on 10-min segments. Longitudinal analysis of indices throughout pregnancy was performed with generalized estimating equations, and receiver operating characteristic (ROC) curves were calculated for the prediction of SGA and PTB fetuses. RESULTS Increasing gestational age significantly affected most FHR indices, with a general increase in variability and entropy indices, and a decrease in mean FHR. The PTB group exhibited a significantly lower short-term variation, and no monotonic increase in the sympatho-vagal balance as observed in the AGA group. The SGA group exhibited higher long-term irregularity and lower short-term irregularity than the AGA group throughout gestation. In prediction of SGA and PTB, the largest areas under the ROC curves obtained were 0.76 and 0.78, respectively. CONCLUSIONS Linear and nonlinear FHR analysis provides useful information on the evolution of fetal autonomic nervous and complexity control systems throughout pregnancy, in relation with AGA, SGA and PTB fetuses, which may be helpful in clinical practice.

Longitudinal changes of cardiotocographic parameters throughout pregnancy: a prospective cohort study comparing small-for-gestational-age and normal fetuses from 24 to 40 weeks.

Abstract Objective: To compare longitudinal trends of cardiotocographic (CTG) parameters between small-for-gestational-age (SGA) and normal fetuses, from 24 to 41 weeks of pregnancy. Methods: A prospective cohort study was carried out in singleton pregnancies without fetal malformations. At least one CTG was performed in each of the following intervals: 24–26 weeks+6 days, 27–29 weeks+6 days, 30–32 weeks+6 days, 33–35 weeks+6 days, 36–38 weeks+6 days and ≥39 weeks. Tracings were analyzed using the Omniview-SisPorto® 3.6 system. Cases with a normal pregnancy outcome, including a birthweight ≥10th percentile for gestational age, were compared with two groups of SGA fetuses: with birthweight <10th percentile (SGA<p10) and <3rd percentile (SGA<p3; a subgroup of the latter). Generalized linear mixed-effects models were used for analysis. Results: A total of 176 fetuses (31 SGA) and 1256 tracings (207 from SGA fetuses) were evaluated. All CTG parameters changed significantly throughout pregnancy in the three groups, with a decreasing baseline and probability of decelerations, and an increasing average long-term variability (LTV), average short-term variability (STV) and accelerations. Baseline showed a more pronounced decrease (steeper slope) in SGA fetuses, being higher in these cases at earlier gestational ages and lower later in pregnancy. Average LTV was significantly lower in SGA<p3 fetuses, but a parallel increase occurred in all groups. There was a considerable inter-fetal variability within each group. Conclusion: A unique characterization of CTG trends throughout gestation in SGA fetuses was provided. A steeper descent of the baseline was reported for the first time. The findings raise the possibility of clinical application of computerized CTG analysis in screening and management of fetal growth restriction.

Cardiotocographic parameters in small‐for‐gestational‐age fetuses: How do they vary from normal at different gestational ages? A study of 11687 fetuses from 25 to 40 weeks of pregnancy

The aim of this study was to assess how cardiotocographic (CTG) parameters differ between small‐for‐gestational‐age (SGA) and normal fetuses at different gestational ages.

Gender-specific evolution of fetal heart rate variability throughout gestation: A study of 8823 cases

BACKGROUND Fetal heart rate (FHR) variability throughout gestation reflects aspects of fetal development, and its analysis has been used for the assessment of fetal well-being. AIM The objective of this study was to provide a gender-specific analysis of the evolution of FHR variability indices throughout gestation, using linear time-domain, spectral and nonlinear FHR indices. STUDY DESIGN A large retrospective study was carried out using antepartum FHR recordings obtained from 4713 male and 4110 female fetuses, with normal pregnancy outcome, between 2004 and 2013, with gestational ages ranging between 25 and 40weeks. OUTCOME MEASURES FHR variability was analysed through linear time-domain methods, as well as using spectral analysis and entropy indices. Evolution of FHR indices throughout gestation was analysed through Spearman correlation coefficient. Comparison between male and female fetuses was performed using nonparametric bootstrap 95% confidence intervals for the median. RESULTS Mean FHR decreased significantly throughout gestation, whereas most variability indices increased. Sympatho-vagal balance measured by spectral analysis exhibited two local maxima at 29-30 and 34-35weeks and decreased afterwards. Entropy indices increased until around the 34th week, slightly decreasing after the 37th week. Female fetuses presented higher mean FHR and entropy from the 34th week afterwards, and lower short-term variability and sympatho-vagal balance in the same period. CONCLUSIONS Spectral and entropy analysis should be considered as a complement to conventional FHR variability analysis, aiming at a better characterization and follow-up of fetal development/maturation throughout gestation. Additionally, gestational age needs to be considered when defining reference ranges for FHR indices in systems of computerized analysis.