This study examined effectiveness of heart rate variability (HRV) biofeedback-assisted stress management training in reducing anxiety and stress in pregnant women and the effect of maternal stress management skills practice on fetal heart rate measures in real time. Participants were seven working pregnant women who volunteered in response to recruitment announcements and invitations from cooperating midwives. Reported state and trait anxiety and pregnancy specific stress were measured during five 45- to 50-minute training sessions. Training included bibliotherapy, instruction in the use of emotion-focused stress management techniques, and HRV biofeedback. Subjects used portable biofeedback units for home practice and were encouraged to practice the skills for 20 minutes a day and for short periods of time during stressful life events. At the end of training, fetal heart rate was monitored and concurrent maternal HRV measures were recorded. Repeated measures ANOVA and paired samples t-test analysis of study data revealed no statistically significant reductions in state or trait anxiety measures or in pregnancy specific stress measures. Partial eta squared (n²) and Cohen's d calculations found small to medium effect sizes on the various test scales. Friedman's analysis of variance of biofeedback measures showed a statistically significant decrease in low HRV coherence scores (X2 = 10.53, p = .03) and medium HRV coherence scores (X2 = 11.58, p = .02) and a statistically significant increase in high HRV coherence scores (X2 = 18.16, p = .001). This change is an indication of improved autonomic function. Results of concurrent maternal and fetal HRV recordings were generally inconclusive. A qualitative discussion of individual subject results is included. During follow-up interviews five subjects reported that they felt they were better able to cope with stress at the end of the study than at the beginning, that they used the stress management skills during labor, and that they continue to practice the skills in their daily lives.

Objetivo: Determinar os valores dopplervelocimétricos normais do fluxo através da valva tricúspide em gestações únicas, entre 11 e 13 semanas e seis dias. Examinar a reprodutibilidade dos parâmetros avaliados e sua correlação com variáveis clínicas maternas e obstétricas. Métodos: Estudo prospectivo envolvendo 166 gestações únicas, com desfecho normal, examinadas entre 11 e 13 semanas e seis dias, no período de fevereiro de 2006 a agosto de 2008. Foram aferidas as velocidades máximas das ondas E e A, duração do ciclo cardíaco completo e sua fase diastólica e calculadas as relações onda E/onda A e diástole/ciclo. Os valores normais foram descritos pelas respectivas médias e desvio-padrão. Para análise da reprodutibilidade desses parâmetros foi calculado o coeficiente de correlação intra-classes em 12 casos examinados por dois examinadores. Regressão linear simples e multivariada foram empregadas para examinar a correlação dos parâmetros dopplervelocimétricos entre si e com a idade gestacional, a medida da translucência nucal e variáveis maternas. Resultados: Neste intervalo gestacional, os valores normais encontrados foram: onda E, 25 (± 4,6) cm/s; onda A, 42,9 (± 5,9) cm/s; relação E/A, 0,58 (± 0,07); ciclo cardíaco, 390 (± 21,1) ms; diástole, 147 (± 18) ms; relação diástole/ciclo, 0,38 (± 0,04). Entre as variáveis dopplervelocimétricas, foi observada correlação significativa entre o ciclo cardíaco e diástole (r=0,53; p<0,0001), diástole e onda A (r=-0,15; p=0,05), ondas E e A (r=0,77; p<0,0001), onda E e relação D/C (r=0,16; p=0,04), onda A e relação diástole/ciclo (r=-0,17; p=0,03). Todas as variáveis, exceto a velocidade da onda A, correlacionaram-se positivamente com a idade gestacional. Não foi observada correlação significativa das variáveis com a medida da translucência nucal, e, na comparação com as variáveis maternas, apenas a onda E e a idade materna apresentaram correlação significativa (r=-0,18, p=0,04). Os coeficientes de correlação intra-classes para a avaliação interobservador e intra-observador (examinadores um e dois) foram: onda E = 0,53 (0,53 e 0,64); onda A = 0,45 (0,46 e 0,49); ciclo cardíaco = 0,70 (0,79 e 0,84) e diástole = 0,63 (0,85 e 0,82). Conclusão: O presente estudo estabeleceu os valores normais dos parâmetros dopplervelocimétricos do fluxo através da valva tricúspide e demonstrou que tais parâmetros, com exceção da onda A, correlacionaram-se de forma positiva com a idade gestacional, e apresentaram reprodutibilidade boa/moderada. / Objective: To establish the measurements of normal tricuspid valve flow velocities at 11 to 13 weeks and 6 days to determine E-wave, A-wave, E/A ratio, cardiac cycle length, diastole length, diastole/cardiac cycle ratio, and their relationship with gestational age, nuchal translucency thickness, the characteristics of the study population, and to assess the reproducibility of flow measurements. Methods: Between February, 2006, and August, 2008, a total of 166 women with a singleton normal pregnancy between 11 and 13 + 6 weeks of gestation consented to participate in the study. Analysis of the waveforms consisted of calculation of peak velocity (cm/s) of the E-wave and A-wave, E-wave/A-wave ratio, cardiac cycle length (ms), diastole length (ms) and diastole/cardiac cycle ratio. To evaluate the intraobserver and interobserver agreement, a subgroup of 12 patients, chosen randomly, was examined twice by each examiner. For descriptive analysis of the results were calculated average and standard deviation. Simple and multivariate linear regression was used to establish the correlation between dopplervelocimetry among parameters and with gestational age, nuchal translucency thickness and the characteristics of the study population. Results: The average (± standard deviation) for transtricuspid flow-velocities waveforms parameters were: E-wave 25 (± 4.6) cm/s; A-wave 42.9 (± 5.9) cm/s; E/A ratio 0.58 (± 0.07); cardiac cycle length 390 (± 21.1) ms; diastole length 147 (± 18) ms; diastole/cardiac cycle length 0,38 (± 0.04). A statistically significant linear increase relative to gestational age was established for all parameters, except A-wave. Nuchal translucency thickness was not correlated with any parameter. A statistically significant negative regression coefficient was established for E-wave to maternal age (r=-0,18, p=0,04). A statistically significant relationship was established between: cardiac cycle length and diastole length (r=0.53; p<0.0001); diastole length and A-wave velocity (r=-0.15; p=0.05); E-wave and A-wave velocities (r=0.77; p<0.0001); E-wave velocity and D/C ratio (r=0.16; p=0.04); A-wave velocity and D/C ratio (r=-0.17; p=0.03). The intraclass correlation coeficients of interobserver and intraobsever evaluations (examiners 1 and 2) were: Ewave = 0.53 (0.53 and 0.64); A-wave = 0.45 (0.46 and 0.49); cardiac cycle = 0.70 (0.79 and 0.84) and diastole= 0.63 (0.85 and 0.82). Conclusions: These data determine normal parameters for tricuspid valve dopplervelocimetry and shows that these parameters, except A-wave, have positive correlation with gestational age, and good/moderate reproducibility.

Objetivo: Determinar os valores dopplervelocimétricos normais do fluxo através da valva tricúspide em gestações únicas, entre 11 e 13 semanas e seis dias. Examinar a reprodutibilidade dos parâmetros avaliados e sua correlação com variáveis clínicas maternas e obstétricas. Métodos: Estudo prospectivo envolvendo 166 gestações únicas, com desfecho normal, examinadas entre 11 e 13 semanas e seis dias, no período de fevereiro de 2006 a agosto de 2008. Foram aferidas as velocidades máximas das ondas E e A, duração do ciclo cardíaco completo e sua fase diastólica e calculadas as relações onda E/onda A e diástole/ciclo. Os valores normais foram descritos pelas respectivas médias e desvio-padrão. Para análise da reprodutibilidade desses parâmetros foi calculado o coeficiente de correlação intra-classes em 12 casos examinados por dois examinadores. Regressão linear simples e multivariada foram empregadas para examinar a correlação dos parâmetros dopplervelocimétricos entre si e com a idade gestacional, a medida da translucência nucal e variáveis maternas. Resultados: Neste intervalo gestacional, os valores normais encontrados foram: onda E, 25 (± 4,6) cm/s; onda A, 42,9 (± 5,9) cm/s; relação E/A, 0,58 (± 0,07); ciclo cardíaco, 390 (± 21,1) ms; diástole, 147 (± 18) ms; relação diástole/ciclo, 0,38 (± 0,04). Entre as variáveis dopplervelocimétricas, foi observada correlação significativa entre o ciclo cardíaco e diástole (r=0,53; p<0,0001), diástole e onda A (r=-0,15; p=0,05), ondas E e A (r=0,77; p<0,0001), onda E e relação D/C (r=0,16; p=0,04), onda A e relação diástole/ciclo (r=-0,17; p=0,03). Todas as variáveis, exceto a velocidade da onda A, correlacionaram-se positivamente com a idade gestacional. Não foi observada correlação significativa das variáveis com a medida da translucência nucal, e, na comparação com as variáveis maternas, apenas a onda E e a idade materna apresentaram correlação significativa (r=-0,18, p=0,04). Os coeficientes de correlação intra-classes para a avaliação interobservador e intra-observador (examinadores um e dois) foram: onda E = 0,53 (0,53 e 0,64); onda A = 0,45 (0,46 e 0,49); ciclo cardíaco = 0,70 (0,79 e 0,84) e diástole = 0,63 (0,85 e 0,82). Conclusão: O presente estudo estabeleceu os valores normais dos parâmetros dopplervelocimétricos do fluxo através da valva tricúspide e demonstrou que tais parâmetros, com exceção da onda A, correlacionaram-se de forma positiva com a idade gestacional, e apresentaram reprodutibilidade boa/moderada. / Objective: To establish the measurements of normal tricuspid valve flow velocities at 11 to 13 weeks and 6 days to determine E-wave, A-wave, E/A ratio, cardiac cycle length, diastole length, diastole/cardiac cycle ratio, and their relationship with gestational age, nuchal translucency thickness, the characteristics of the study population, and to assess the reproducibility of flow measurements. Methods: Between February, 2006, and August, 2008, a total of 166 women with a singleton normal pregnancy between 11 and 13 + 6 weeks of gestation consented to participate in the study. Analysis of the waveforms consisted of calculation of peak velocity (cm/s) of the E-wave and A-wave, E-wave/A-wave ratio, cardiac cycle length (ms), diastole length (ms) and diastole/cardiac cycle ratio. To evaluate the intraobserver and interobserver agreement, a subgroup of 12 patients, chosen randomly, was examined twice by each examiner. For descriptive analysis of the results were calculated average and standard deviation. Simple and multivariate linear regression was used to establish the correlation between dopplervelocimetry among parameters and with gestational age, nuchal translucency thickness and the characteristics of the study population. Results: The average (± standard deviation) for transtricuspid flow-velocities waveforms parameters were: E-wave 25 (± 4.6) cm/s; A-wave 42.9 (± 5.9) cm/s; E/A ratio 0.58 (± 0.07); cardiac cycle length 390 (± 21.1) ms; diastole length 147 (± 18) ms; diastole/cardiac cycle length 0,38 (± 0.04). A statistically significant linear increase relative to gestational age was established for all parameters, except A-wave. Nuchal translucency thickness was not correlated with any parameter. A statistically significant negative regression coefficient was established for E-wave to maternal age (r=-0,18, p=0,04). A statistically significant relationship was established between: cardiac cycle length and diastole length (r=0.53; p<0.0001); diastole length and A-wave velocity (r=-0.15; p=0.05); E-wave and A-wave velocities (r=0.77; p<0.0001); E-wave velocity and D/C ratio (r=0.16; p=0.04); A-wave velocity and D/C ratio (r=-0.17; p=0.03). The intraclass correlation coeficients of interobserver and intraobsever evaluations (examiners 1 and 2) were: Ewave = 0.53 (0.53 and 0.64); A-wave = 0.45 (0.46 and 0.49); cardiac cycle = 0.70 (0.79 and 0.84) and diastole= 0.63 (0.85 and 0.82). Conclusions: These data determine normal parameters for tricuspid valve dopplervelocimetry and shows that these parameters, except A-wave, have positive correlation with gestational age, and good/moderate reproducibility.

Τα τελευταία χρόνια τόσο σε διεθνές όσο και σε εθνικό επίπεδο έχει δοθεί βαρύτητα στην ανίχνευση της εμβρυϊκής υποξίας κατά τη διάρκεια της κύησης και του τοκετού, καθώς είναι σαφής η άμεση συσχέτισή της με βραχυπρόθεσμες και απώτερες επιπλοκές του νεογνού. Η επιτυχής έκβαση ενός τοκετού εξαρτάται κυρίως από τον έγκαιρο εντοπισμό της δημιουργίας της εμβρυϊκής υποξίας και η ανάγκη για την υλοποίηση υπολογιστικών συστημάτων για την έγκαιρη διάγνωσή της είναι συνεχής και αυξανόμενη. Στα πλαίσια της διδακτορικής διατριβής σχεδιάστηκε και αναπτύχθηκε ένα πρωτότυπο σύστημα διάγνωσης της πρόωρης οξέωσης του εμβρύου κατά τη διάρκεια του τοκετού, το οποίο βασίστηκε στην επεξεργασία του εμβρυϊκού καρδιακού ρυθμού και στην ανάλυση της εμβρυϊκής παλμικής οξυμετρίας. Στόχος του συγκεκριμένου συστήματος είναι να αποτελέσει ένα βοηθητικό σύστημα διάγνωσης της εμβρυϊκής υποξίας και να συμβάλει στη λήψη αποφάσεων σχετικά με το χρόνο αποπεράτωσης του τοκετού, με σκοπό την πρόληψη άμεσων και απώτερων σοβαρών νεογνικών επιπλοκών. Ειδικότερα, η υλοποίηση του προτεινόμενου συστήματος βασίστηκε στην εφαρμογή του συνεχούς μετασχηματισμού κυματιδίων και της προσαρμοστικής προσέγγισης με τη χρήση του αλγορίθμου matching pursuit για την ανάδειξη της «κρυμμένης» πληροφορίας που μεταφέρει ο εμβρυϊκός καρδιακός ρυθμός στις πολύ χαμηλές συχνότητες. Συνδυάζοντας τα αποτελέσματα των παραπάνω τεχνικών επεξεργασίας, και ιδιαίτερα του αλγορίθμου matching pursuit, με τον προσδιορισμό του συνολικού χρόνου χαμηλού κορεσμού του αρτηριακού εμβρυϊκού αίματος, υλοποιήθηκε, με τη χρήση ενός διαμεριστικού αλγορίθμου, το προτεινόμενο σύστημα. Η ανάπτυξη αυτού του συστήματος αποτελεί μια καινοτόμα και πολλά υποσχόμενη προσέγγιση στην προσπάθεια της διάγνωσης της εμβρυϊκής υποξίας δεδομένου ότι παρουσιάζει υψηλή ειδικότητα και θετική προγνωστική αξία συμβάλοντας στην επίλυση του σοβαρότερου μειονεκτήματος της κλασσικής καρδιοτοκογραφίας που είναι η χαμηλή τιμή των αντίστοιχων προγνωστικών δεικτών. / In the last few years the research community has given great attention to the detection of antepartum and intrapartum fetal hypoxia, given its direct impact on both short- and long-term neonatal morbidity and mortality. The successful completion of labor depends mainly on the prompt identification of fetal hypoxia. The development of computational systems for the early diagnosis of restricted fetal oxygen supply is therefore of critical importance. This thesis involves the design and development of an innovative system for the early detection of acidosis, which was based on the fetal heart rate processing and fetal pulse oximetry analysis. The aim of the system is to comprise a computer-aided diagnostic system of fetal hypoxia and to contribute to the decision making regarding the labor completion time, in order to prevent short- and long-term neonatal complications. Specifically, the development of the system was based on the implementation of continuous wavelet transform and adaptive approximation using the matching pursuit algorithm, in order to reveal the “hidden” information conveyed in the very low frequency range of the fetal heart rate. The system involves the combination of the results of the above-mentioned processing techniques, and especially of the matching pursuit algorithm, along with the calculation of the duration of fetal arterial low oxygen saturation, applying a commonly used clustering algorithm. The proposed system is an innovative and promising approach towards the early diagnosis of fetal hypoxia, given its high specificity and positive predictive value, thus effectively addressing the major drawback of clinical cardiotocography.

This thesis addresses the task of developing automatic algorithms for analysing the two-dimensional ultrasound video footage obtained from fetal heart screening scans. These scans are typically performed in the second trimester of pregnancy to check for congenital heart anomalies and require significant training and anatomical knowledge to perform. The aim is to develop a tool that runs at high frame rates with no user initialisation and infers the visibility, position, orientation, view classification, and cardiac phase of the heart, and additionally the locations of cardiac structures of interest (such as valves and vessels) in a manner that is robust to the various sources of variation that occur in real-world ultrasound scanning. This is the first work to attempt such a detailed automated analysis of these videos. The problem is posed as a Bayesian filtering problem, which provides a principled framework for aggregating uncertain measurements across a number of frames whilst exploiting the constraints imposed by anatomical feasibility. The resulting inference problem is solved approximately with a particle filter, whose state space is partitioned to reduce the problems associated with filtering in high-dimensional spaces. Rotation-invariant features are captured from the videos in an efficient way in order to tackle the problem of unknown orientation. These are used within random forest learning models, including a novel formulation to predict circular-valued variables. The algorithm is validated on an annotated clinical dataset, and the results are compared to estimates of inter- and intra-observer variation, which are significant in both cases due to the inherent ambiguity in the imagery. The results suggest that the algorithm's output approaches these benchmarks in several respects, and fall slightly behind in others. The work presented here is an important first step towards developing automated clinical tools for the detection of congenital heart disease.

O objetivo do presente estudo foi verificar a frequência cardíaca fetal e as respostas cardiorrespiratórias de gestantes e não-gestantes, durante e ao longo de 30 minutos após a execução de exercícios de força para membros superiores e inferiores, em dois volumes distintos. A amostra desse estudo foi composta por 20 mulheres, com idade entre 20 e 32 anos, sendo 10 gestantes (com idade gestacional entre 22 e 24 semanas) e 10 não-gestantes, que realizaram cinco sessões experimentais: sessão 1: familiarização com os equipamentos de coletas de dados e determinação de uma repetição máxima estimada; sessões 2, 3, 4 e 5: coleta das variáveis cardiorrespiratórias durante e ao longo de 30 minutos após os exercícios de força nos equipamentos cadeira extensora de joelhos bilateral e voador peitoral, com 1 e 3 séries de 15 repetições, com carga de 50% de uma repetição máxima estimada. Utilizou-se ANOVA para medidas repetidas com 2 e 3 fatores, com post-hoc de Bonferroni (α=0,05) (SPSS vs 13.0). Os resultados demonstraram que as respostas de pressão arterial durante os exercícios de força apresentam um comportamento mais baixo no grupo gestantes. Quando estes foram realizados com série única, somente a frequência cardíaca e o duplo produto apresentaram respostas diferentes entre os exercícios, com maiores valores no exercício extensor de joelhos bilateral, entretanto, quando os exercícios foram realizados com séries múltiplas, as respostas das variáveis frequência cardíaca, pressão arterial sistólica, diastólica e média, duplo produto, ventilação e consumo de oxigênio absoluto foram diferentes entre os exercícios, com maiores valores no exercício extensor de joelhos bilateral. As variáveis analisadas apresentaram diferenças ao longo dos 30 minutos de recuperação pós-exercício, em geral, retornando aos valores basais após 10 minutos do término do exercício. Não houve ocorrência de contrações uterinas em nenhuma gestante ao longo deste período. A resposta da frequência cardíaca fetal não apresentou diferenças nos diferentes exercícios e volumes e ao longo dos 30 minutos de recuperação pós-exercício e se manteve dentro dos padrões de normalidade (120-160 bpm). Conclui-se que, durante a realização dos exercícios de força extensor de joelhos bilateral e voador peitoral, as respostas de pressão arterial de gestantes foram menores do que as não-gestantes, o exercício extensor de joelhos bilateral apresentou maiores valores das variáveis cardiorrespiratórias comparado ao exercício voador e as variáveis apresentaram aumento das suas respostas com o aumento do número de séries realizadas. A resposta fetal não diferiu entre os exercícios e volumes. / The aim of the present study was to verify fetal heart rate and the cardiorespiratory responses in pregnant and non-pregnant women during and along 30 minutes postexecution of resistance exercises for upper and lower body, with two different volumes. The sample was composed of 20 healthy women, aged between 20-32 years old, being 10 pregnant women (gestational age between 22 and 24 weeks) and 10 non-pregnant women, who performed five experimental sessions: session 1: familiarization with the equipments and the determination of one estimated maximum repetition (1-RM); sessions 2, 3, 4 and 5: determination of the cardiorespiratory responses during and along 30 minutes post-resistance exercise on the bilateral leg extension and fly, with 1 and 3 sets of 15 repetitions, 50% of 1-RM. Results were analyzed using ANOVA for repeated measures with two and three factors with Bonferroni correction for post-hoc comparisons (α=0.05) (SPSS vs 13.0). The blood pressure responses during resistance exercises showed a lower behavior in the pregnant group. When the exercises were performed with a single set, only heart rate and rate-pressure product showed different responses between exercises, with increased values for bilateral leg extension, however, when the exercises were performed with multiple sets the heart rate, systolic, diastolic and mean blood pressure, rate-pressure product, ventilation and oxygen uptake responses were different between exercises, with increased values for bilateral leg extension. The analyzed variables showed differences along 30 minutes post-exercise but in general it was similar to those pre-exercise values after 10 minutes from the end of the resistance exercise. There was no occurrence of uterine contractions along this period. The fetal heart rate responses did not presented differences between the exercises and volumes and along the 30 minutes post-resistance exercise and kept the normality patterns (120-160 bpm). In conclusion, during the performance of the bilateral leg extension and fly resistance exercises the blood pressure response was lower in the pregnant group. The bilateral leg extension showed higher values for the cardiorespiratory variables compared to fly exercise and the variables responses presented an increase with the addition of the sets performed. The fetal response was not different between exercises and volumes performed.

O objetivo do presente estudo foi verificar a frequência cardíaca fetal e as respostas cardiorrespiratórias de gestantes e não-gestantes, durante e ao longo de 30 minutos após a execução de exercícios de força para membros superiores e inferiores, em dois volumes distintos. A amostra desse estudo foi composta por 20 mulheres, com idade entre 20 e 32 anos, sendo 10 gestantes (com idade gestacional entre 22 e 24 semanas) e 10 não-gestantes, que realizaram cinco sessões experimentais: sessão 1: familiarização com os equipamentos de coletas de dados e determinação de uma repetição máxima estimada; sessões 2, 3, 4 e 5: coleta das variáveis cardiorrespiratórias durante e ao longo de 30 minutos após os exercícios de força nos equipamentos cadeira extensora de joelhos bilateral e voador peitoral, com 1 e 3 séries de 15 repetições, com carga de 50% de uma repetição máxima estimada. Utilizou-se ANOVA para medidas repetidas com 2 e 3 fatores, com post-hoc de Bonferroni (α=0,05) (SPSS vs 13.0). Os resultados demonstraram que as respostas de pressão arterial durante os exercícios de força apresentam um comportamento mais baixo no grupo gestantes. Quando estes foram realizados com série única, somente a frequência cardíaca e o duplo produto apresentaram respostas diferentes entre os exercícios, com maiores valores no exercício extensor de joelhos bilateral, entretanto, quando os exercícios foram realizados com séries múltiplas, as respostas das variáveis frequência cardíaca, pressão arterial sistólica, diastólica e média, duplo produto, ventilação e consumo de oxigênio absoluto foram diferentes entre os exercícios, com maiores valores no exercício extensor de joelhos bilateral. As variáveis analisadas apresentaram diferenças ao longo dos 30 minutos de recuperação pós-exercício, em geral, retornando aos valores basais após 10 minutos do término do exercício. Não houve ocorrência de contrações uterinas em nenhuma gestante ao longo deste período. A resposta da frequência cardíaca fetal não apresentou diferenças nos diferentes exercícios e volumes e ao longo dos 30 minutos de recuperação pós-exercício e se manteve dentro dos padrões de normalidade (120-160 bpm). Conclui-se que, durante a realização dos exercícios de força extensor de joelhos bilateral e voador peitoral, as respostas de pressão arterial de gestantes foram menores do que as não-gestantes, o exercício extensor de joelhos bilateral apresentou maiores valores das variáveis cardiorrespiratórias comparado ao exercício voador e as variáveis apresentaram aumento das suas respostas com o aumento do número de séries realizadas. A resposta fetal não diferiu entre os exercícios e volumes. / The aim of the present study was to verify fetal heart rate and the cardiorespiratory responses in pregnant and non-pregnant women during and along 30 minutes postexecution of resistance exercises for upper and lower body, with two different volumes. The sample was composed of 20 healthy women, aged between 20-32 years old, being 10 pregnant women (gestational age between 22 and 24 weeks) and 10 non-pregnant women, who performed five experimental sessions: session 1: familiarization with the equipments and the determination of one estimated maximum repetition (1-RM); sessions 2, 3, 4 and 5: determination of the cardiorespiratory responses during and along 30 minutes post-resistance exercise on the bilateral leg extension and fly, with 1 and 3 sets of 15 repetitions, 50% of 1-RM. Results were analyzed using ANOVA for repeated measures with two and three factors with Bonferroni correction for post-hoc comparisons (α=0.05) (SPSS vs 13.0). The blood pressure responses during resistance exercises showed a lower behavior in the pregnant group. When the exercises were performed with a single set, only heart rate and rate-pressure product showed different responses between exercises, with increased values for bilateral leg extension, however, when the exercises were performed with multiple sets the heart rate, systolic, diastolic and mean blood pressure, rate-pressure product, ventilation and oxygen uptake responses were different between exercises, with increased values for bilateral leg extension. The analyzed variables showed differences along 30 minutes post-exercise but in general it was similar to those pre-exercise values after 10 minutes from the end of the resistance exercise. There was no occurrence of uterine contractions along this period. The fetal heart rate responses did not presented differences between the exercises and volumes and along the 30 minutes post-resistance exercise and kept the normality patterns (120-160 bpm). In conclusion, during the performance of the bilateral leg extension and fly resistance exercises the blood pressure response was lower in the pregnant group. The bilateral leg extension showed higher values for the cardiorespiratory variables compared to fly exercise and the variables responses presented an increase with the addition of the sets performed. The fetal response was not different between exercises and volumes performed.

O objetivo do presente estudo foi verificar a frequência cardíaca fetal e as respostas cardiorrespiratórias de gestantes e não-gestantes, durante e ao longo de 30 minutos após a execução de exercícios de força para membros superiores e inferiores, em dois volumes distintos. A amostra desse estudo foi composta por 20 mulheres, com idade entre 20 e 32 anos, sendo 10 gestantes (com idade gestacional entre 22 e 24 semanas) e 10 não-gestantes, que realizaram cinco sessões experimentais: sessão 1: familiarização com os equipamentos de coletas de dados e determinação de uma repetição máxima estimada; sessões 2, 3, 4 e 5: coleta das variáveis cardiorrespiratórias durante e ao longo de 30 minutos após os exercícios de força nos equipamentos cadeira extensora de joelhos bilateral e voador peitoral, com 1 e 3 séries de 15 repetições, com carga de 50% de uma repetição máxima estimada. Utilizou-se ANOVA para medidas repetidas com 2 e 3 fatores, com post-hoc de Bonferroni (α=0,05) (SPSS vs 13.0). Os resultados demonstraram que as respostas de pressão arterial durante os exercícios de força apresentam um comportamento mais baixo no grupo gestantes. Quando estes foram realizados com série única, somente a frequência cardíaca e o duplo produto apresentaram respostas diferentes entre os exercícios, com maiores valores no exercício extensor de joelhos bilateral, entretanto, quando os exercícios foram realizados com séries múltiplas, as respostas das variáveis frequência cardíaca, pressão arterial sistólica, diastólica e média, duplo produto, ventilação e consumo de oxigênio absoluto foram diferentes entre os exercícios, com maiores valores no exercício extensor de joelhos bilateral. As variáveis analisadas apresentaram diferenças ao longo dos 30 minutos de recuperação pós-exercício, em geral, retornando aos valores basais após 10 minutos do término do exercício. Não houve ocorrência de contrações uterinas em nenhuma gestante ao longo deste período. A resposta da frequência cardíaca fetal não apresentou diferenças nos diferentes exercícios e volumes e ao longo dos 30 minutos de recuperação pós-exercício e se manteve dentro dos padrões de normalidade (120-160 bpm). Conclui-se que, durante a realização dos exercícios de força extensor de joelhos bilateral e voador peitoral, as respostas de pressão arterial de gestantes foram menores do que as não-gestantes, o exercício extensor de joelhos bilateral apresentou maiores valores das variáveis cardiorrespiratórias comparado ao exercício voador e as variáveis apresentaram aumento das suas respostas com o aumento do número de séries realizadas. A resposta fetal não diferiu entre os exercícios e volumes. / The aim of the present study was to verify fetal heart rate and the cardiorespiratory responses in pregnant and non-pregnant women during and along 30 minutes postexecution of resistance exercises for upper and lower body, with two different volumes. The sample was composed of 20 healthy women, aged between 20-32 years old, being 10 pregnant women (gestational age between 22 and 24 weeks) and 10 non-pregnant women, who performed five experimental sessions: session 1: familiarization with the equipments and the determination of one estimated maximum repetition (1-RM); sessions 2, 3, 4 and 5: determination of the cardiorespiratory responses during and along 30 minutes post-resistance exercise on the bilateral leg extension and fly, with 1 and 3 sets of 15 repetitions, 50% of 1-RM. Results were analyzed using ANOVA for repeated measures with two and three factors with Bonferroni correction for post-hoc comparisons (α=0.05) (SPSS vs 13.0). The blood pressure responses during resistance exercises showed a lower behavior in the pregnant group. When the exercises were performed with a single set, only heart rate and rate-pressure product showed different responses between exercises, with increased values for bilateral leg extension, however, when the exercises were performed with multiple sets the heart rate, systolic, diastolic and mean blood pressure, rate-pressure product, ventilation and oxygen uptake responses were different between exercises, with increased values for bilateral leg extension. The analyzed variables showed differences along 30 minutes post-exercise but in general it was similar to those pre-exercise values after 10 minutes from the end of the resistance exercise. There was no occurrence of uterine contractions along this period. The fetal heart rate responses did not presented differences between the exercises and volumes and along the 30 minutes post-resistance exercise and kept the normality patterns (120-160 bpm). In conclusion, during the performance of the bilateral leg extension and fly resistance exercises the blood pressure response was lower in the pregnant group. The bilateral leg extension showed higher values for the cardiorespiratory variables compared to fly exercise and the variables responses presented an increase with the addition of the sets performed. The fetal response was not different between exercises and volumes performed.

La surveillance du bien-être fœtal pendant le travail repose essentiellement sur l’enregistrement du rythme cardiaque fœtal (RCF). Celui-ci, même continu pendant le travail, ne permet pas d’évaluer parfaitement l’oxygénation du fœtus ni le risque d’asphyxie néonatale. En effet, cet outil est imparfait et son évaluation subjective avec une importante variabilité d’interprétation inter et intra opérateur. Des examens dits de seconde ligne sont utilisés en pratique courante pour caractériser l’état fœtal : le prélèvement de sang fœtal au scalp pour l’étude de l’équilibre acido-basique du fœtus (pH ou lactates) ou la pose d’électrode au scalp pour étudier l’ECG fœtal (analyse du segment ST). Ces techniques sont néanmoins invasives et sont soumises à des contraintes techniques. Il y a donc un intérêt à développer des moyens d’évaluation du bien être fœtal à la fois objectifs et non invasifs afin de diminuer la survenue d’une asphyxie périnatale. En effet, celle-ci touche 3 à 8 nouveaux nés pour 1000 naissances. La mortalité en période post-natale est de 25 à 50% des cas et ceux qui survivent développeront des troubles sévères (épilepsie, retard neuro-cognitif et comportemental, paralysie cérébrale…). Au cours de l’accouchement, l’asphyxie périnatale se caractérise par une diminution du pH artériel ombilical. Cette mesure du pH sanguin est donc la mesure de référence pour déterminer la sévérité de l’asphyxie.Une des voies étudiées pour améliorer le dépistage des fœtus à risque d’acidose est l’analyse des modifications du système nerveux autonome (SNA) par analyse de la variabilité du rythme cardiaque fœtal. En effet, la fréquence cardiaque fœtale est en permanence sous l’influence du système nerveux autonome et sa variabilité (VFC) est un reflet de la balance sympathique / parasympathique. Le CHU de Lille a développé une nouvelle méthode d’analyse continue de la VFC ayant montré son efficacité chez l’adulte et chez le nouveau né pour l’évaluation du SNA. L’objectif de ce travail de Thèse est d’adapter cette technologie à l’analyse du SNA fœtal pour obtenir un nouvel indice appelé Fetal Stress Index (FSI) et d’évaluer sa pertinence en situation d’acidose.Cette preuve de concept a été effectuée de manière expérimentale chez le fœtus de brebis. Elle s’est réalisée en 2 temps. Nous avons tout d’abord évalué la performance du FSI par rapport aux méthodes classiques d’analyse de la VFC en termes d’aptitude à détecter les variations du SNA. Après injection d’Atropine, parasympatholytique, ou de Propranolol, sympatholytique, nous avons montré que le FSI était une méthode efficace et spécifique d’évaluation des variations du tonus parasympathique du SNA. Cette étude a également montrée la supériorité du FSI par rapport aux méthodes classiques d’analyse de la VFC en termes de sensibilité et de spécificité. Dans un second temps, nous avons évalué ce nouvel indice comme facteur prédictif de l’état acido basique du fœtus dans 2 modèles expérimentaux d’occlusion cordonale. Dans le premier modèle, l’acidose était obtenue par une occlusion continue du cordon avec une réduction de partielle du débit ombilical. Dans le second, nous réalisions des occlusions totales répétées à intervalles réguliers afin de mimer les contractions utérines lors du travail. Dans les 2 études, nous avons observé une hausse du FSI en cas d’acidose avec une corrélation significative entre le FSI et le pH, mais aussi entre le FSI et les lactates dans le second modèle.En conclusion, le FSI constitue un bon reflet de l’activité parasympathique fœtale. Cet indice permet d’étudier les variations du SNA fœtal avec une meilleure sensibilité et une meilleure spécificité que les méthodes usuelles d’analyse de la VFC et semble bien corrélé à l’état acido basique fœtal. Il s’agit donc d’un indice prometteur qu’il sera intéressant d’incorporer dans une analyse multi paramétrique du rythme cardiaque fœtal. / The monitoring of fetal well being during labor is essentially based on fetal heart rate (FHR) analysis. The recording of FHR, even continuously during labor, does not fully assess fetal oxygenation or neonatal risk of asphyxia. Indeed, this tool is imperfect and subjective with an important inter and intra-operator variability. Second-line examinations to characterize the fetal state are currently used in routine practice, i.e. scalp fetal blood sampling to study the fetal acid-base balance (pH or lactates) or scalp electrode placement to study the fetal ECG (ST segment analysis). These techniques are nevertheless invasive and subject to technical constraints. There is therefore an interest in developing both objective and non-invasive means of evaluating fetal wellbeing to reduce neonatal encephalopathy. Indeed, its prevalence is about 3 to 8 per 1000 births. Post natal mortality is about 25 to 50% and survivors will hav severe diseases (epilepsy, neurologic impairment, cerebral palsy…).One of the possibilities studied to better identify fetuses at risk for acidosis is the analysis of changes in the autonomic nervous system (ANS) in response to hypoxia.Indeed, the regulation of heart rate is dependent on the ANS and thus, its variability is a reflection of the sympathetic / parasympathetic balance. Analysis of heart rate variability (HRV) is a recognized non-invasive tool that is used to assess ANS regulation. The CHU Lille has developed a new continuous tool for the analysis of HRV, which demonstrated its efficacity in adults and neonates to evaluate the ANS. The objective of this thesis was to develop its index, called Fetal Stress Index (FSI), in the fetus and to evaluate it in conditions of acidosis.The study was experimental in a sheep model chronically instrumented and was in 2 steps. First, we evaluate the performance of our method compared to commonly used HRV analysis, regarding the ability to detect the variation of variations of the ANS. After injection of atropine, to inhibit parasympathetic tone, or propranolol to block sympathetic activity, we shown that our method appeared to be effective in detecting parasympathetic inhibition and, moreover, was superior to classical analysis of HRV in terms of sensibility and specificity.In a second time, we evaluated this new index as a predictive factor of the fetal acid-base state in 2 experimental models of fetal hypoxia by occlusion of the cord. In the first one, acidosis was obtained through a partial occlusion of the umbilical cord and in the second one, though repetitive complete occlusion as uterine contractions during labor. In those two studies, we observed a raise of our index in case of acidosis with a correlation beetween FSI and pH and also FSI and lactates in the second model.In conclusion, the FSI reflects fetal parasympathetic activity, has a better detection than others usual methods, and seems well correlated to fetal acid-base status. It is a promising index and it will be interesting to incorporate it in a multi parametric analysis of fetal heart rate to predict acidosis.

Die nicht-invasive Analyse der fetalen Herzratenvariabilität mittels abdominaler Elektrokardiographie stellt eine neue Methode zur Beurteilung des fetalen Zustandes dar. Die Herzratenvariabilität gilt hier als ein sensitives Maß der autonomen Regulation. Bereits mit Beginn der zweiten Schwangerschaftshälfte ist es möglich, über das mütterliche Abdomen ein fetales Elektrokardiogramm abzuleiten und einer Herzratenvariabilitätsanalyse zuzuführen. Das Untersuchungskollektiv dieser Arbeit umfasste Frauen mit frühem vorzeitigem Blasensprung als Modell einer pathologischen Alteration des fetalen Zustandes sowie Frauen mit normalen Schwangerschaften zwischen der 20. und 28. Schwangerschaftswoche. Die technische Umsetzung und Analyse der fetalen Herzratenvariabilität erfolgte in Kooperation mit dem Institut für Biomedizinische Technik der TU Dresden. Insgesamt wurden 25 Datensätze der Auswertung zugeführt. Eine Reifung des autonomen Nervensystems des Feten mit ansteigendem Gestationsalter konnte mittels der Herzratenvariabilitätsanalyse gezeigt werden. Zur Risikostratifizierung der Feten bei frühem vorzeitigem Blasensprung konnten bei der Betrachtung der Herzratenvariabilitätsparameter keine signifikanten Unterschiede zum Normalkollektiv erhoben werden. Die Analyse der Parameter erfolgte hierbei unabhängig von den fetalen Verhaltenszuständen. Es konnte gezeigt werden, dass die nicht-invasive Analyse der Herzratenvariabilitätsanalyse methodisch und technisch in der Lage ist, den Fetalzustand und dessen Alterationen zu erfassen.