Objetivo: Avaliar o perfil de citocinas pró-inflamatórias e de melatonina no cordão umbilical e no sangue materno de gestantes hígidas de acordo com a via de parto. Métodos: Entre março e setembro de 2010, foi realizado estudo observacional prospectivo no Hospital Universitário da Universidade de São Paulo. Foram dosadas citocinas (IL-1, IL-6, TNF) e melatonina em pacientes sem doenças clínicas ou complicações obstétricas que entraram em trabalho de parto espontâneo. As concentrações de citocinas e de melatonina foram comparadas de acordo com a via de parto, além do período do dia e do local de coleta. O sangue retirado da veia do cordão umbilical (VCU) era obtido imediatamente após o parto, sendo que após uma hora era colhido o sangue da veia braquial materna (VB). Foram excluídas pacientes com infecção, parto prematuro e sofrimento fetal. Resultados: Foram estudadas 50 parturientes, das quais 25 evoluíram para parto vaginal e 25 para cesárea. A idade materna foi em média 26,0 ± 6,7 anos. A idade gestacional no parto foi em média 39,5 ± 1,7 semanas. O peso médio dos recém-nascidos foi 3366,5 ± 340,2 gramas. Todos os casos receberam analgesia durante o parto (analgesia combinada: peridural e raquianestesia). A maioria das pacientes era de nulíparas (31/50 - 62,0%). A duração do trabalho de parto foi semelhante nas pacientes que evoluíram para o parto vaginal (7,6 ± 4,4 horas) e nas que foram submetidas à operação cesariana (8,2 ± 4,4 horas; p=0,87). Houve tendência de níveis mais elevados de melatonina no VCU e na VB em pacientes após parto vaginal, porém sem diferença estatística (p=0,41 e p=0,16). Pacientes que evoluíram para cesariana apresentaram dosagens significativamente maiores de TNF na VB, de IL-1 na VCU e na VB e de IL-6 na VCU que em pacientes que evoluíram para parto vaginal (p= 0,02; p<0,01; p<0,01 e p<0,01; respectivamente). Observou-se variação no ritmo circadiano das dosagens dessas citocinas após cesariana, com correlação significativa entre dosagem de melatonina e de citocinas nessa via de parto. Conclusão: Pacientes submetidas à operação cesariana apresentaram tendência a redução da secreção de melatonina, com aumento significativo da secreção de citocinas pró-inflamatórias, o que pode ser conseqüência do processo inflamatório relacionado ao estresse cirúrgico / Objetive: To evaluate the profile of pro-inflammatory cytokines and the melatonin level in maternal and umbilical cord blood samples in accordance with the mode of delivery. Methods: Between March 2010 and September 2010, a prospective observational study was conducted at University Hospital of University of São Paulo. Cytokines (IL-1, IL-6, TNF) and melatonin levels were analyzed from maternal brachial vein (BV) and umbilical cord vein (UCV) obtained from healthy patients that started spontaneous labor. The levels of cytokines and melatonin were evaluated in accordance to the mode of delivery as well as the day period and the local of blood sample (UCV - immediately after delivery and BV - one hour after delivery). Patients with infection, preterm labor and fetal distress were excluded. Results: A total of 50 patients were evaluated in the present study: 25 underwent vaginal delivery and 25 c-section. Mean maternal age was 26.0 ± 6.7 years. Mean gestational age at delivery was 39.5 ± 1.7 weeks. The average of newborn weight was 3366.5 ± 340.2 grams. All patients had combined epidural and raquianesthesia. The majority of the patients was nullipara (31/50 62.0%). The labor duration was similar in patients that underwent vaginal delivery (7.6 ± 4.4 hours) or c-section (8.2 ± 4.4 hours, p=0.87). There was a tendency of increased levels of melatonin in the UCV and BV samples after vaginal deliveries, but with statistical significance (p=0.41 and p=0.16). Patients that underwent c-section had increased levels of TNF at the BV, IL-1 at the UCV and BV and IL-6 at the UCV than in patients that underwent vaginal delivery (p= 0.02; p<0.01; p<0.01 and p<0.01; respectively). Circadian variations of the cytokines and the melatonin levels were observed in patients that underwent c-section, with significant correlation between the levels of cytokines and melatonin. Conclusion: Patients that underwent c-section had a tendency of reduced melatonin level, with significant increase in the cytokine levels, which may be consequent of the inflammatory process related to the surgical stress.

Este trabalho tem como propósito investigar através do método Design Construtal a influência do espaçamento (S0) entre cilindros de seção transversal elíptica na maximização da densidade de transferência de calor em um escoamento externo sob efeito de convecção forçada. A razão de aspecto (r) entre os eixos vertical e horizontal dos cilindros elípticos também é um parâmetro avaliado. O estudo proposto é assumido bidimensional, incompressível, laminar e permanente. O regime de escoamento é dirigido por uma diferença de pressão ΔP, que se mantém através do domínio e é governada pelo número de Bejan (Be). Foram avaliados escoamentos com quatro diferentes números de Bejan, Be = 102, 103, 5.103, 104. O fluido que escoa através do domínio possui as propriedades termofisicas definidas pelo número de Prandtl, Pr = 0,72. O método Design Construtal, associado à busca exaustiva, foi empregado para determinar as restrições, graus de liberdade e o objetivo na avaliação geométrica do sistema A solução numérica das equações de conservação de massa, quantidade de movimento e energia foram resolvidas baseadas no método de volumes finitos, através do código comercial de dinâmica dos fluidos computacional FLUENT®. As geometrias e malha do domínio computacional foram desenvolvidas no pacote GAMBIT®. Como resultados, obteve-se que os casos ótimos apresentaram resultados consideravelmente melhores do que as demais configurações, onde se obteve ganhos de desempenho na densidade de transferência de calor de 50% a 97% em relação às configurações de menor desempenho estudadas. Além disso, foi possível verificar que o sistema adapta sua geometria ótima para cada condição de escoamento, a fim de proporcionar a melhor arquitetura de fluxo para atender ao objetivo térmico de maximizar a transferência de calor em um menor espaço físico, atendendo os princípios da Teoria Construtal. / This work investigates, through the Construtal Design method, the influence of the spacing (S0) between cylinders with elliptic cross in the maximization of the heat transfer density in an external flow with forced convection. The aspect ratio (r) between the vertical and horizontal axes of the elliptical cylinders is also evaluated. The proposed study is assumed twodimensional, incompressible, laminar and permanent. The flow regime is directed by a pressure difference ΔP, which is governed by the Bejan number (Be). The flows were evaluated for different values of the Bejan number, Be = 102, 103, 5.103, 104. The fluid flowing through the domain has its thermophysical properties defined by Prandtl number, Pr = 0.72. The Construtal Design method, associated with the exhaustive search, was used to determine the restrictions, degrees of freedom and objective in the geometric evaluation of the system. The numerical solution of the mass conservation, momentum and energy equations is solved based on the finite volume method, using the commercial fluid dynamics software FLUENT ®. The geometries and mesh of the computational domain were developed in the GAMBIT® package. The results show that the optimal cases performs considerably better than the other configurations, with an increase in the heat transfer density of 50% to 97% in comparison to the performance of lower level cases studied. In addition, it was possible to verify that the system adapts its optimal geometry to every flow condition in order to provide a better flow architecture that meets the thermal objective of maximizing a heat transfer in a smaller physical space in agreement with the principles of the Constructal Theory.

Ce travail présente l'étude de faisabilité des mesures de transmission avec des échantillons MINERVE à l'installation de temps de vol GELINA. L'idée principale était de définir des procédures pour analyser les résultats des mesures de transmission réalisées avec des échantillons cylindriques ne répondant pas à la géométrie de transmission idéale. La capacité d'extraire des résultats fiables a été démontrée sur l'exemple des échantillons MINERVE enrichis en argent. De plus, des mesures de transmission et de capture avec des disques standards d'argent naturel ont été effectuées pour améliorer les paramètres de résonance pour 107Ag et 109Ag. Les principales étapes de ce travail sont la réduction des données brutes (taux de comptage) pour produire des spectres de transmission et de rendement de capture, puis l'analyse des spectres avec le code d'analyse de forme des résonances REFIT. / This work presents the feasibility study of transmission measurements with the MINERVE samples at time-of-flight facility GELINA. The main idea was to define procedures to analyse results of transmission measurements using cylindrical samples which do not fulfil the ideal transmission geometry. Capability of extracting reliable results was demonstrated on the example of MINERVE samples enriched in silver. In addition, transmission and capture measurements with standard discs of natural silver were performed to improve the resonance parameters for 107Ag and 109Ag. The main steps in this work are the data reduction of measured count rate spectra to produce final transmission and capture yield spectra and the spectra analysis with the resonance shape analysis code REFIT.

Orientador: Cristina Maria Garcia de Lima Parada / Resumo: Introdução: Na literatura científica, estudos relacionam as cesáreas ao aumento do risco de morbimortalidade materna e infantil. Além dos possíveis desfechos negativos observados no período perinatal, a literatura tem apontado, também, efeitos deletérios na primeira infância para crianças nascidas por operação cesariana, tais como: desmame precoce, asma, alergia e alterações de crescimento. Porém, com exceção do aleitamento materno e da asma, há viés na maioria dos registros, visto que não há a devida discriminação entre os desfechos relacionados às cesáreas indicadas e as cesáreas eletivas. A tese a ser explorada diz respeito aos efeitos adversos da cesárea no período perinatal e primeiro ano de vida, quando realizada sem indicação precisa, tendo como hipótese: os desfechos da cesárea eletiva são negativos no período perinatal e no primeiro ano de vida quando comparados aos mesmo desfechos do parto vaginal. Objetivos específicos: três estudos foram desenvolvidos, sendo que o primeiro, tem por objetivo classificar os tipos de partos de acordo com três referências: Federação Brasileira das Associações de Ginecologia e Obstetrícia (FEBRASGO), Ministério da Saúde (Comissão Nacional de Incorporação de Tecnologia no Sistema Único de Saúde – CONITEC) e revisão de literatura especialmente conduzida para tal finalidade e comparar os desfechos perinatais e no primeiro ano de vida associados a essas classificações; o segundo objetiva verificar o efeito da cesárea eletiva sobre os desfe... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Introduction: In the scientific literature, studies have linked cesarean sections to an increased risk of maternal and infant morbidity and mortality. In addition to the possible negative outcomes observed in the perinatal period, the literature has also pointed out deleterious effects in early childhood for children born by cesarean section, such as early weaning, asthma, allergy and growth disorders. However, with the exception of breastfeeding and asthma, there are biases in most registries, since there is no proper discrimination between outcomes related to indicated cesarean sections and elective cesarean sections. The thesis to be explored concerns the adverse effects of cesarean section in the perinatal period and first year of life, when performed without precise indication, with the hypothesis: elective cesarean outcomes are negative in the perinatal period and in the first year of life when compared to vaginal delivery outcomes. Specific objectives: three studies were developed, the first of which aims to classify the types of deliveries according to three references: Brazilian Federation of Associations of Gynecology and Obstetrics (FEBRASGO), Ministry of Health (National Commission for the Incorporation of Unitary Health System - CONITEC) and literature review conducted for this purpose and to compare the perinatal outcomes and in the first year of life associated with these classifications; the second objective was to verify the effect of elective cesarean sectio... (Complete abstract click electronic access below) / Doutor

Afin de répondre au problème de santé publique que représente l'asthme, l'imagerie tomodensitométrique associé aux traitements informatiques permettent la quantification et le suivi des dommages subis par les bronches. Le but de l'imagerie bronchique, lors d'un examen de type scanner-CT est de disposer de mesures fiables et reproductibles des différents paramètres bronchiques qui sont des marqueurs de l'importance de la pathologie et de son évolution sous traitements. Ces marqueurs correspondent à deux mesures LA ( Lumen Area) et WA ( Wall Area) prises sur des coupes perpendiculaires à la bronche. La mise en place d'une chaîne de traitements constitué de maillons d'extraction et de squelettisation de l'arbre trachéo-bronchique permet l'obtention de tels mesures. Durant cette thèse nous nous sommes focalisés sur la création d'une chaîne de traitements en proposant une contribution sur chacun des maillons. Notre chaîne est modulable et adaptée au travail en 4D (différentes phases respiratoires) et à fait l'objet d'une implémentation logiciel intitulée Neko4D. / [Abstract not provided]

Les matériaux absorbants électromagnétiques, ou « Radar Absorbing Materials » (RAM), ont été créés à la fois aux USA et en Allemagne lors de la seconde guerre mondiale. Les applications des absorbants appartiennent principalement aux domaines de la Compatibilité ElectroMagnétique (CEM) et de la discrétion radar. Ces absorbants sont lourds et encombrants. Au travers de cette thèse, nous cherchons à développer une solution pour pallier à ces inconvénients grâce aux absorbants à métamatériaux. Les métamatériaux sont des composites artificiels présentant des propriétés électromagnétiques que l'on ne retrouve pas dans la nature. En utilisant ce type de matériaux, nous pouvons obtenir des absorbants ultras fins, et par l'optimisation et la conception couvrir des bandes larges en fréquence. Nous proposons donc plusieurs formes basiques d'absorbant à métamatériaux. De ces formes, nous présentons un modèle théorique et développons les techniques pour définir leur fréquence de fonctionnement et les paramètres nécessaires pour obtenir une absorption totale. Puis nous étudions plus en détail nos différents prototypes à travers des simulations et des mesures. Nous étudions aussi le couplage des absorbants à métamatériaux avec des absorbants traditionnels pour créer un type d'absorbant inédit. / Electromagnetic absorbing materials, or "Radar Absorbing Materials" (RAM), were created in the U.S. and Germany at the same time during the Second World War. Applications of absorbers are mainly in the field of ElectroMagnetic Compatibility (EMC) and radar stealth. These absorbers are heavy and bulky. In this thesis, we seek to develop a solution to overcome these drawbacks using metamaterial absorbers. Metamaterials are artificial composites with electromagnetic properties that are not found in nature. By using this type of material, we can obtain ultra-thin absorbers over a wide band of frequency by optimizing the design. We introduce several basic forms of metamaterial absorbers. From these geometries, we present a theoretical model and we develop techniques to define their operating frequency and parameters required to achieve total absorption. Then we study in detail our various prototypes with simulations and measurements. We also study the coupling of metamaterial absorbers with traditional ones to create a new type of absorber.

Na maioria das situações relacionadas aos estudos da Terra, um método geofísico não é suficiente para chegar a uma conclusão de uma questão específica, já que o mesmo é passivo de ambiguidades ou incertezas na interpretação. Para tal, se faz necessário que um ou mais métodos sejam integrados, gerando uma resposta que se aproxime do modelo real e com confiabilidade para que a mesma metodologia possa ser aplicada em outros casos similares, otimizando assim a utilização conjunta dos métodos. Partindo desse ponto o presente trabalho sugere a realização de uma Modelagem Gravimétrica 2-D, auxiliada por dados sísmicos e de poços, visando o mapeamento das estruturas profundas da bacia de Santos, já que o conhecimento sobre as mesmas é de grande importância para estudos tectônicos para reconstrução histórica da bacia que servem de parâmetro de entrada nos estudos de modelagem visando reconstruir os processos de geração, migração e acumulação de hidrocarbonetos. / In most situations related to Earth studies, a geophysical method is not sufficient to reach a conclusion of a specific issue, since it is Carrie ambiguities or uncertainties in your interpretation. For that reason, it is necessary integrate one or more methods for generating a response that approximates the real Earth with reliability so that the same methodology can be applied in other similar cases, thus optimizing the combined use of methods. From this point this project suggests the implementation of a 2D Gravity Modeling, aided by seismic and wells data, aimed at mapping the depth of the basement and your characterization in the northern portion of the Santos Basin, because knowledge about the crust is of great importance for tectonic studies of basin historical reconstruction that serve as input parameter in modeling studies aimed at reconstructing the processes of generation, migration and accumulation of hydrocarbons.

Cette thèse porte sur l’analyse et la modélisation des interactions électromagnétiques sur des torons aéronautiques constitués de câbles multiconducteurs représentatifs de la réalité industrielle. En effet les évolutions technologiques (introduction de matériaux composites, augmentation des fonctions électriques,..) conduisent à revoir les niveaux d’exigence des couplages électromagnétiques sur torons de câbles. Ainsi, les outils de dimensionnement de ces couplages s’avèrent indispensables pour décider des choix technologiques d’architectures des câblages.Dans ce contexte, les codes numériques basés sur la théorie des lignes de transmission permettent de calculer les couplages électromagnétiques au sein de torons multiconducteurs. Ces modèles numériques doivent être alimentés par la description géométrique des sections droites de toron. Un outil logiciel de génération de sections droites de toron a étévalidé dans un premier temps par comparaison à une référence bibliographique, puis par une étude expérimentale d’un toron réel d’A380. Cette étude de suivi de positionnement de conducteur dans le toron a mis en évidence que le cheminement des câbles au sein du toron dépendait de leur rigidité. Ainsi, la bifilaire torsadée non blindée est le câble dont le cheminement est le moins maîtrisé. De plus, ce type de câble très couramment utilisé pour transmettre desdonnées en mode différentiel, est à l’origine de couplages spécifiques qu’il est essentiel d’analyser pour correctement les modéliser. Par conséquent, le premier cas étudié est composé d’une bifilaire torsadée agresseur et d’une monofilaire victime. Les simulations numériques ont montré que les courants induits le long de la monofilaire victime présentaient un motif propre à la torsade de la bifilaire agresseur. Ce motif a été expliqué par une approche analytique et confirmé par expérimentations. La prise en compte des torsades dans une simulation numérique induisant des temps de calculs prohibitifs, un modèle simplifié de câble torsadé basé sur un moyennage des paramètres linéiques a été développé et validé. L’effet des extrémités dé-torsadées résultant de la connectorisation a également été évalué d’un point de vue numérique et expérimental. Les cas d’étude ont ensuite été complexifiés à des couplages entre bifilaires torsadées jusqu’à traiter un toron réel de plus de 60 conducteurs. Un banc expérimental a été développé. La modélisation numérique de ce toron complexe a été réalisée et les résultats numériques de couplages électromagnétiques confrontés aux données expérimentales. En vue de réduire considérablement les temps de calculs, le modèle simplifié a étéappliqué à ce toron. Sa potentialité a été démontrée. Une analyse statistique de la dispersion des couplages lectromagnétiques au sein de ce toron complexe a finalement été abordée. / This thesis focuses on the analysis and the modeling of electromagnetic interactions on aeronautical bundles made of multicore cables representative of the industrial reality. Indeed, technological changes (introduction of composite materials, increased electrical functions, ...) force to reconsider the requirement levels of electromagnetic coupling on cable bundles. Thus, the design tools of these electromagnetic couplings are essential to help to technological choices of architectureswiring. In this context, numerical software based on transmission line theory can calculate the electromagnetic coupling in complex bundles. These numerical models need the geometric description of bundles cross sections. A software tool for generating bundles cross sections was initially validated by comparison to a bibliographic reference, followed by anexperimental study of a real bundle arised from an A380. This analysis of conductors positioning along the bundle showed that the cable routing depends on the cable stiffness. Thus, the unshielded twisted cable appears to be the cable which routing is less controlled. In addition, this type of cable most commonly used to tr nsmit data in differential mode can generate specific couplings which are important to analyze for correctly modeling this cable. Therefore, the first case studied is composed of a twisted pair cable aggressor and a single victim wire. Numerical simulations have shownthat the induced currents along the victim wire had a behavior specific to the twist of the twisted pair cable aggressor. This pattern has been explained by an analytical approach and confirmed by experiments. Taking into account twists in numerical simulation leads to prohibitive computational time. Therefore, a simplified model based on averagingparameters per unit length of twisted cable was developed and validated. The effect of untwisted ends resulting from connection was also assessed numerically and experimentally. Case studies were complicated to coupling between twisted pair cabl es and finally to a real bundle with more than 60 wires. An experimental bench was developed. Numerical modeling of the complex bundle has been carried out and numerical results of electromagnetic couplings compared to experimental data. In order to significantly reduce the computation time, the simplified model was applied to this bundle. Itsefficiency has been demonstrated. A statistical analysis of the dispersion of electromagnetic couplings within this complex bundle was finally addressed.

A existência de seções globais para uxos é de central importância na teoria de sistemas dinâmicos, pois uma seção global simplica o estudo da dinâmica de um uxo reduzindo-o ao estudo da dinâmica de um difeomorsmo. Apresentamos detalhadamente a construção feita Hofer, Zehnder e Wysocki (em \'\'The dynamics on a strictly convex energy surface in R4\'\') de uma seção global para o uxo Hamiltoniano restrito a um nível de energia convexo em R4 . Uma importante consequência da existência dessa seção global é que o uxo Hamiltoniano restrito a um nível de energia convexo em R4 tem 2 ou innitas órbitas periódicas. Essa construção utiliza-se da teoria de curvas pseudo-holomorfas em simplectizações de variedades de contato desenvolvida pelos mesmos autores. Os argumentos apresentados também dão uma nova prova da Conjectura de Weinstein para formas de contato tight em S3 . / The existence of global surfaces of section to ows is of central importance in the theory of dynamical systems, as a global surface of section simplies the study of the dynamics of a ow reducing it to the study of the dynamics of a dieomorphism. We present in detail the construction due to Hofer, Wysocki and Zehnder (in \'\'The dynamics on a strictly convex energy surface in R4\'\') of a global surface of section for the Hamiltonian ow restricted to a convex energy level in R4 . An important consequence of the existence of the global surface of section is that the Hamiltonian ow restricted to a convex energy level in R4 has either 2 or innitely many periodic orbits. This construction makes use of the theory of pseudo-holomorphic curves in symplectizations of contact manifolds developed by the same authors. The arguments also give a new proof of Weinstein conjecture for tight contact forms in S3 .

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Objetivos: avaliar a influÃncia da via de parto sobre os resultados perinatais, em mulheres que tiveram parto prematuro (PP); avaliar caracterÃsticas demogrÃficas e obstÃtricas como determinantes da via de parto. Sujeitos e mÃtodos: estudo transversal, a partir dos prontuÃrios de mulheres que tiveram PP, acompanhadas no ServiÃo de Medicina Materno-Fetal da Maternidade-Escola Assis Chateaubriand â Universidade Federal do CearÃ. Foram analisadas 195 gestantes e os 195 recÃm-nascidos (RNs) oriundos dessas gestaÃÃes, Ãnicas, sem complicaÃÃes clÃnicas maternas, fetais e obstÃtricas, apresentando idade gestacional (IG) entre 22 e 36 semanas e seis dias e com peso fetal igual ou acima de 500 gramas. As caracterÃsticas demogrÃficas e obstÃtricas e os resultados perinatais foram avaliados na populaÃÃo geral e em cada grupo (partos vaginal e abdominal), sendo posteriormente comparados entre si. Para a avaliaÃÃo estatÃstica comparativa entre os dois grupos, utilizou-se o teste de Mann-Whitney. O cÃlculo da razÃo de risco ajustado foi realizado atravÃs do software SAS versÃo 9.1.3 e atravÃs de RegressÃo LogÃstica e Multivariada. Todos foram considerados estatisticamente significantes quando p<0.05. Resultados: a maioria das gestantes (81.5%) foi admitida em trabalho de parto prematuro (TPP) ativo espontÃneo e 43.1% apresentaram bolsa rota. Agentes tocolÃticos e corticosteroides foram usados, respectivamente, em 41.6% e 58.3% das mulheres em prÃdromo de TPP e a maioria dos partos (74.4%) ocorreu por via vaginal. No momento do parto, a IG mÃdia foi 32.6 semanas. Quando os dois grupos foram comparados, o prÃdromo de TPP, a bolsa rota e a administraÃÃo de tocolÃticos e corticoides aumentaram, significativamente, o risco de cesÃrea (RRs 6.10, 1.64, 1.95 e 1.82, respectivamente), enquanto o TPP ativo diminuiu, significativamente, esse risco (RR 0.16, IC 95% - 0.11 a 0.25). O peso mÃdio dos RNs foi 1873g, sendo classificados como adequados para IG em 76.7%. Necessitaram de internamento em UTI 62.1% dos casos, 21% usaram surfactante, 90.8% necessitaram de ventilaÃÃo mecÃnica, 4.6% apresentaram tocotraumatismos e o Ãndice de Ãbito neonatal foi de 8.7%. Quando se compararam os dois grupos, a cesÃrea aumentou, significativamente, a chance do Ãndice de Apgar ao 5Â minuto ser &#8805; 7 (RR 1.06, IC 95% - 1.01 a 1.13). ApÃs regressÃo logÃstica de COX, ajustada para fatores que poderiam influenciar nos resultados perinatais, nÃo foram observadas diferenÃas estatisticamente significativas entre os dois grupos. ConclusÃes: nÃo foram encontradas diferenÃas estatisticamente significativas nos resultados perinatais entre RNs de partos vaginal e abdominal de mulheres que tiveram parto prematuro. Quanto Ãs caracterÃsticas obstÃtricas, o prÃdromo de TPP, a bolsa rota e o uso de agentes tocolÃticos e corticoides aumentaram, significativamente, o risco de cesÃrea, enquanto o TPP ativo diminuiu, significativamente, esse risco. / Objectives: to evaluate the influence of route of delivery on perinatal outcomes, in women who had preterm delivery; to evaluate demographic and obstetric characteristics as determinants of mode of delivery. Subjects and methods: it is a cross-sectional study from the charts of women who had preterm delivery, followed in the Service of Maternal-Fetal Medicine of Maternidade-Escola Assis Chateaubriand â Universidade Federal do CearÃ. There were analyzed 195 pregnant women and 195 newborns coming from these singleton pregnancies, without clinical maternal, fetal and obstetric complications, presenting gestational age between 22 and 36 weeks and six days and fetal weight equal or above 500 grams. Demographic and obstetric characteristics and perinatal outcomes were evaluated in the general population and in each group (vaginal and abdominal delivery), being later compared with each other. For comparative statistical analysis among the two groups, it was utilized the Mann-Whitney test. The calculation of the reason of adjusted risk was accomplished through the software SAS version 9.1.3 and through Logistical and Multinomial Regression. All were considered statistically significant when p < 0.05. Results: the majority of pregnant women (81.5%) was admitted in active spontaneous preterm labor and 43.1% had premature rupture of the membranes. Tocolytic agents and corticosteroids were used, respectively, in 41.6% and 58.3% of women in false preterm labor and most of deliveries (74.4%) happened by vaginal route. At the moment of delivery, the average gestational age was 32.6 weeks. When the two groups were compared, false preterm delivery, premature rupture of the membranes and the administration of tocolytic drugs and corticosteroids increased, significantly, the risk of cesarean section (RRs 6.10, 1.64, 1.95 e 1.82, respectively), while the active preterm delivery decreased, significantly, this risk (RR 0.16, 95% CI - 0.11 a 0.25). The mean weight of the newborns was 1873g and they were classified as appropriate for gestational age in 76.7%. They needed for admission to the intensive care unit in 62.1% of cases, 21% required surfactant, 90.8% needed mechanic ventilation, 4.6% presented neonatal injury and the index of neonatal death was 8.7%. When the two groups were compared, the cesarean section significantly increased the chance of the Apgar score at 5Â minute to be &#8805; 7 (RR 1.06, 95% CI - 1.01 a 1.13). After logistic regression of COX adjusted for factors that could influence perinatal outcomes, had not been observed statistically significant differences between the two groups. Conclusions: it had not been found statistically significant differences in perinatal outcomes among newborns of vaginal delivery and cesarean section in women who had preterm delivery. Regarding obstetric characteristics, false preterm delivery, premature rupture of the membranes and the use of tocolytic agents and corticosteroids increased, significantly, the risk of cesarean section while the active preterm delivery decreased, significantly, this risk.