The United States is ranked 27th in the world for maternal mortality, yet spends twice as much on maternity care services as countries with better maternal health indicators. Stuck in a technocratic and physician-dominated maternity care system, the U.S. depends on expensive technologies to control birth out of fear of pain and litigation, costing Americans billions of dollars and depriving women of the opportunity to have a transformative birth experience. Through an analysis of the medicalization of birth and the current biomedical model in birth, in conjunction with open-ended interviews with 5 hospital midwives and 3 homebirth midwives, the benefits and challenges of incorporating a midwifery model of care into our maternity services are explored. The midwifery model emphasizes that birth is not pathology and that psychosocial factors play a large role in birth outcomes. Basing their practice on collaboration, education, and support, midwives empower women, avoid unnecessary interventions, and offer a lower cost and higher quality care alternative. The current monopoly of women’s health services by physicians is unsustainable. Incorporating midwives into the maternity care team could provide a sustainable alternative with the caliber of maternity care services that U.S. women and families deserve.

<p>Background: Globally, neonatal mortality (i.e. deaths occurring during the first month of life) accounts for 44% of the 11 million infants that die every year (Lawn, Cousens &amp / Zupan, 2005). Early&nbsp / detection of illness and referral of mothers and infants during the peri-natal period to higher levels of care can lead to substantial reductions in maternal and child mortality in developing&nbsp / countries. Establishing effective referral systems from the community to health facilities can be achieved through greater utilization of community health workers and improved health seeking&nbsp / behaviour. Study design: The Good Start Saving Newborn Lives study being conducted in Umlazi, KwaZulu-Natal, is a community randomized trial to assess the effect of an integrated home&nbsp / visit package delivered to mothers during pregnancy and post delivery on uptake of PMTCT interventions and appropriate newborn care practices. The home visit package is delivered by community health workers in fifteen intervention clusters. Control clusters receive routine health facility antenatal and postpartum care. For any identified danger signs during a home visit,&nbsp / community health workers write a referral and if necessary refer infants to a local clinic or hospital. The aim of this study was to assess the effectiveness of this referral system by describing&nbsp / community health worker referral completion rates as well as health-care seeking practices and perceptions of mothers. A cross- sectional survey was undertaken using a structured&nbsp / questionnaire with all mothers who had been referred to a clinic or hospital by a community health worker since the start of the Good Start Saving Newborn Lives Trial. Data collection: Informed consent was obtained from willing participants. Interviews were conducted by a trained research assistant in the mothers&rsquo / home or at the study&nbsp / offices. Road to Health Cards were reviewed to confirm referral completion. Data was collected by means of a cell phone (mobile researcher software) and the database was later transferred to Epi-info and STATA IC 11 for analysis.&nbsp / Descriptive analysis was&nbsp / conducted so as to establish associations between explanatory factors and referral completion and to describe referral processes experienced by caregivers. Significant&nbsp / associations between categorical variables were assessed using chi square tests and continuous variables using analysis of variance. Results: A total of 2423 women were&nbsp / enrolled in the SNL study and 148 had received a referral for a sick infant by a CHW by June 2010. The majority (95%) of infants were referred only once during the time of enrolment, the&nbsp / highest number of which occurred within&nbsp / the first 4 weeks of life (62%) with 22% of these being between birth and 2 weeks of age. Almost all mothers (95%) completed the referral by taking&nbsp / their child to a health facility. Difficulty in breathing and rash accounted for the highest number of referrals (26% and 19% respectively). None of the six mothers who did not complete referral recognised any danger signs in their infants. In only 16% of cases did a health worker give written feedback on the outcome of the referral to the referring CHW.&nbsp / Conclusion: This study found&nbsp / high compliance with referrals for sick infants by community health workers in Umlazi. This supports the current primary health care re-engineering process being undertaken by the South&nbsp / African National Department of Health (SANDOH) which will involve the establishment of family health worker teams&nbsp / including community health workers. A key function of these workers will&nbsp / be to conduct antenatal and postnatal visits to women in their homes and to identify and refer ill children. Failure of mothers to identify danger signs in the infant was associated with&nbsp / non-completion of referral. This highlights the need for thorough counseling of mothers during the antenatal and early postnatal period on neonatal danger signs which can be reinforced by&nbsp / community health workers. Most of the referrals in this study were&nbsp / neonates which strengthens the need for home visit packages delivered by community health workers during the antenatal&nbsp / and post-natal period as currently planned by the South African National Department of Health.Recommendations: This study supports the current plans of the Department of Health for greater involvement of CHWs in Primary Health Care. Attention should be given to improving communication between health facilities and CHWs to ensure continuity of care and greater&nbsp / realization of a team approach to PHC.</p>

Pregnancy and childbirth complications are a leading cause of death and disability among women of reproductive age in developing countries. Worldwide data shows that, by choice or out of necessity, 60 percent of births in the developing world occur outside a health institution and 47 percent are assisted by Traditional Birth Attendants (TBAs), family members, or without any assistance at all. This thesis argues that TBAs in India have the capacity to disseminate knowledge of beneficial maternal practices to the community. Since the 1970s the training of TBAs has been one of the primary single interventions encouraged by World Health Organisation (WHO) to address maternal mortality. However, since the 1990s international funding for TBAs has been reduced and the emphasis has shifted to providing skilled birth attendants for all births due to evidence that the maternal mortality rate (MMR) in developing countries had not reduced. Researchers have observed that the shift in policy has taken place without adequate evidence of training (in)effectiveness and without an alternative policy in place. This thesis argues further that two main types of birthing knowledge co-exist in India; western biomedicine and traditional knowledge. Feminist, anthropological, and midwifery theorists contend that when two knowledge paradigms exist, western knowledge tends to dominate and claim authority over local ways of knowing. The thesis used such theories, and quantitative and qualitative methods, to assess whether the local TBA training programmes in Ahmednagar District in India have been successful in disseminating biomedical knowledge in relation to the birthing practices of local TBAs and in incorporating local knowledge into the training. The data revealed that some biomedical knowledge had been successfully disseminated and that some traditional practices continue to be practiced in the community. There is a top-down, one-sided imposition of biomedical knowledge on TBAs in the training programme but, at the local level, TBAs and mothers sometimes follow the training instructions and sometime do not, preferring to adapt to the local perceptions and preferences of their community. The thesis reveals the significance of TBA training in the district but queries the effectiveness of not including local TBA practices into the training programmes, arguing this demonstrates the hierarchical authority of biomedicine over local traditional practices. The thesis highlights the significance of community awareness that accompanies TBA training and makes recommendations in order to enhance training outcomes.

In 2013, 2 million people were newly infected with HIV, and 11% of those new infections were infants that obtained the disease from their mother. In resource poor settings, like Sub-Saharan Africa, infection rates from mother to child can range from 15-45%. With proper prevention of mother to child transmission (MTCT), these rates can drop to 5%. Proper prevention includes the use of antiretroviral treatment (ART) during pregnancy, delivery, and post-partum and breastfeeding. In 2010, WHO proposed a model that required all HIV positive mothers to receive ART. The model successfully increased the amount of women on treatment, and many countries also saw a decrease in the rate of MTCT, however barriers still exist. In my thesis, I explain how HIV attacks an individual’s immune system, and why it has been such a difficult epidemic to control in regards to mother to child transmission. I also examine how different models of prevention are successful, and why Option B+, proposed by WHO in 2010, has been the most successful. Lastly, I propose new additions to the model in an attempt to circumvent the barriers.

Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / O objetivo principal desta Dissertação foi avaliar as relações entre a Violência Física entre Parceiros Íntimos (VFPI) nos primeiros seis meses após o parto e a utilização de serviços de saúde entre crianças menores de seis meses de idade. Para estudar o construto utilização de serviços de saúde utilizou-se o momento de início do acompanhamento e o número de consultas da criança em Unidades Básicas de Saúde (UBS). Adicionalmente, estimou-se a prevalência de VFPI nos primeiros seis meses após o parto entre mães de crianças desta faixa etária assistidas nas UBS do Rio de Janeiro. As informações que subjazem a pesquisa originaram-se de um estudo transversal realizado em 27 UBS do Município do Rio de Janeiro, entre junho e setembro de 2007. A população de estudo foi selecionada por meio de amostragem por conglomerado em dois estágios. As UBS unidades primárias de amostragem foram amostradas com probabilidade de seleção proporcional ao volume de consultas pediátricas realizadas conduzindo a uma amostra geograficamente representativa do município. As crianças unidades secundárias de amostragem foram selecionadas de forma sistemática, obedecendo à ordem de saída das consultas. A amostra incluiu 927 crianças nos primeiros seis meses de vida cujas mães relataram ter companheiro na ocasião da entrevista dentre aquelas que buscaram consulta pediátrica ou de puericultura. As informações foram obtidas por meio de entrevista com a mãe da criança utilizando-se um questionário estruturado, contendo escalas previamente validadas, como a Revised Conflict Tatics Scales (CTS2) para a mensuração da VFPI. O artigo inicial apresenta a prevalência de VFPI nos primeiros seis meses após o parto na população estudada e em certos subgrupos de acordo com características sociodemográficas e de saúde de mães e bebês. Elevadas frequências de violência conjugal foram evidenciadas, em especial entre mães em situação socioeconômica desfavorável e que apresentavam falhas no cuidado pré-natal, na amamentação e na utilização do serviço de saúde. Os outros dois artigos apontam que a VFPI após o parto apresenta um sério risco ao acompanhamento regular da criança nos serviços de saúde. O segundo artigo revelou que a VFPI é um fator de risco independente para o início tardio do acompanhamento da criança em UBS em mulheres que possuíam emprego informal ou não trabalhavam e entre aquelas que não haviam realizado um adequado acompanhamento pré-natal. Já o terceiro artigo mostrou que a VFPI aumenta o risco de crianças filhas de mães que não exerciam trabalho remunerado após o parto terem um número de consultas aquém do esperado para a idade nos seus primeiros seis meses de vida. Espera-se que a divulgação dos resultados desta Dissertação possa contribuir para aumentar a sensibilização de profissionais de saúde e dos planejadores de políticas públicas do Setor Saúde para a importância de ações de combate à violência e, assim, colaborar para a promoção da saúde no seu sentido mais amplo.

O presente trabalho procurou analisar a inserção da psicanálise nas novas formas de cuidado terapêutico em perinatologia, mais precisamente, no domínio que envolve os acontecimentos que ocorrem entre a concepção e os 36 meses de vida da criança. Para tanto, inicialmente foi apresentada a área da saúde materno-infantil no Brasil e as políticas públicas que a sustentam. Em seguida, delineou-se o funcionamento do campo escolhido, no caso uma maternidade de alto risco. Tendo em vista, a construção de uma rede de atenção tecida a partir de diferentes olhares, se procurou enfocar os impasses da interseção entre o discurso biomédico, o da educação em saúde e o da psicanálise. Nesse ponto, foi utilizada como referência principal a contribuição de D. W. Winnicott sobre a teoria do amadurecimento pessoal. Com a finalidade de circunscrever o crescente interesse pela primeira infância, procedeu-se a um mapeamento do estudo psicanalítico dos primórdios do psiquismo, após uma breve incursão pelo texto freudiano. Promoveu-se ainda uma discussão sobre o encontro das hipóteses psicanalíticas com as novas descobertas científicas sobre as potencialidades do bebê, ressaltando as consequências possíveis de tal intercâmbio. Por fim, foram destacadas algumas concepções que fundamentam a importância do olhar psicanalítico para o cuidado integral à saúde materno-infantil, enfatizando autores como Lebovici, Cramer, Bydlowski e Golse. Aqui as discussões teóricas entrelaçaram-se com observações de campo e vinhetas clínicas

Virus-specific cellular immune responses have been shown to be important in the control of viral replication in several animal and human virus models. Cells of both the CD8+ and CD4+T cell lineages have been shown to play protective roles during viral infections by exerting effector functions that can kill infected host cells or inhibit the production and spread of infectious virions. The continued spread of HIV-1 infection throughout the world, as well as the lack of a prophylactic HIV-1 vaccine have generated much interest in HIV-specific cellular immune responses. Recent technical advances have yielded a tremendous increase in our understanding of HIV-1-specific immunity, as well as HIV-1 replication dynamics and host cell factors that shape the course of acute and chronic infection. Unfortunately, due to small sample volumes and technological limitations, the study of HIV-1-specific T cell immunity in infants and children has been difficult. An improved understanding of the timing, specificity, and intensity of pediatric HIV-specific T cell responses would contribute to the development of a HIV-1 vaccine for use in regions of the developing world without access to antiretroviral therapeutics. In the small number of published studies investigating pediatric HIV-specific immunity, T cell responses were uncommonly detected in infants. It remains unclear, however, whether the lack of HIV-specific T cells is an accurate reflection of the in vivoimmune state in vertically-infected infants, or rather is a consequence of reagents and assays ill-suited to the detection of low-level and/or diverse T cell responses in pediatric subjects. In the present dissertation, several methodologies were used to investigate HIV-specific T cell responses in vertically-infected infants and children. HIV-specific CD8+ T cell responses were infrequently detected in a cohort of young infants, but are commonly detected in older infants and children. Interestingly, CMV-specific CD8+ T cell responses were detected in several young infants that lacked HIV-specific responses, suggesting a specific defect in the ability of some infants to generate HIV-specific CD8+ T cell responses. Further experiments characterizing detectable HIV-1-specific CD8+ T cell responses found that the HIV-1 accessory proteins may be important targets of the immune response during early vertical infection. The role of HLA class I genotype and viral sequence are also explored in a pair of vertically-infected twins with discordant CD8+T cell responses. Finally, viral isolates from an infant with a marked shift in gag-specific epitope usage during infancy are analyzed for the presence of escape mutations. Gag-specific CD4+ T cell responses were commonly detected in a large cohort of vertically-infected children. A linear relationship between HIV-1 replication and the presence and intensity of HIV-specific CD4+ T cell responses was found, but ongoing HIV-1 replication appeared to blunt CD4+T cell proliferation. The data presented in this dissertation describe pediatric T cell immune responses and how they relate to HIV-1 replication. This information may be useful to the design of a prophylactic or therapeutic HIV-1 vaccine for vertically-infected infants and children.

BACKGROUND: Breastfeeding and lactation are cited as sensitive periods in the life course that contribute to the accumulation of risks or opportunities ultimately shaping vulnerability or resilience later in life. As such, breastfeeding and lactation are critical components of health equity. Despite this, Black women in the U.S. initiate and continue to breastfeed at lower rates than White women and other groups. Underlying reasons for racial inequities in breastfeeding rates are poorly understood. Exposure to racism, one manifestation of historical oppression in the U.S. has been cited as a determinant of poor health outcomes for decades but has not been extensively described in the context of breastfeeding. AIMS: To investigate the association between experiences of racism and 1.) breastfeeding initiation 2.) breastfeeding duration 3.) and the association between selected life-course factors and breastfeeding initiation and duration among participants of the Black Women’s Health Study. METHODS: This study was a prospective secondary analysis of the Black Women’s Health Study. The sample included all participants who enrolled in 1995, responded to the racism assessment in 1997 and reported the birth of a first child following the racism assessment resulting in an N=2, 995 for the initiation outcome and N= 2,392 for the duration outcome. In addition to the racism assessment, we also included life-course factors (nativity, neighborhood segregation and social mobility). For each aim, we calculated odds ratios and 95% confidence intervals using binomial and multinomial logistic regression using two models. The first adjusted for age, the second adjusted for age, BMI, education, marital status, geographic region, neighborhood SES and occupation. RESULTS: Associations between daily and institutional summary racism variables and breastfeeding initiation and duration were small and not statistically significant. Experiences of racism in the job setting was associated with lower odds of breastfeeding duration at 3-5 months compared with 3 months 95% CI [0.60, 0.98]. Experiences of racism with the police was associated with higher odds of breastfeeding initiation and duration at 3-5 months [1.01, 1.77] and at 6 months [1.10, 1.82] compared with women who did not report this experience. The participant’s nativity and the nativity of her parents were life-course factors that predicted lower odds of breastfeeding initiation and duration. Neighborhood segregation did not reach statistical significance after adjusting for covariates but results trended toward lower odds of breastfeeding initiation and duration for women who reported living in a predominately Black neighborhood (compared with White) up to age 18 and for women who reported living in a predominately Black neighborhood in 1999. CONCLUSION: Experiences of institutional racism in the job setting was associated with lower odds of breastfeeding duration. In addition to explicit experiences of racism, this study provides preliminary evidence surrounding life-course factors and breastfeeding. Individual level interventions may mitigate harmful effects of racism but structural level interventions are critical to close the gap of racial inequity in breastfeeding rates in the U.S.

Este trabalho teve como objetivo analisar a construção de uma representação cultural sobre a incompetência feminina para gestar e parir por meio da análise das trajetórias assistenciais de mulheres atendidas no subsetor suplementar de atenção à saúde de Porto Alegre, RS. Procurou-se problematizar o contexto social e cultural da vivência da gestação e do parto das mulheres atendidas por planos ou seguros saúde, compreendendo a gestação e o nascimento como processos culturais e inseridos na contemporaneidade. Para tanto foi realizado um estudo etnográfico de abril a novembro de 2014 na cidade de Porto Alegre, RS, com a participação de oito mulheres gestantes, atendidas por planos de saúde e que estavam com mais de 32 semanas de gestação. Os dados foram produzidos por meio de observação participante, anotações em diário de campo e entrevistas semi estruturadas, as quais foram gravadas e transcritas na íntegra. O processo analítico foi orientado pela antropologia interpretativa, tendo como base o referencial teórico sobre Cultura de Clifford Geertz. Foi possível apreender as trajetórias assistenciais das mulheres acompanhadas, desenhando caminhos de modulação e resistência. Apreendeu-se visões complexas e subjetivas sobre a gestação e o parto, sempre compreendidas em meio a cultura em que as mulheres viviam e experencivam estes processos. As redes sociais apresentam-se como elementos moduladores sobre os ideais de maternidade e escolhas do parto. A gestação é compreendida por um olhar medicalizado, orientando à ideia de que a mulher não deve envolver-se com a gravidez e o parto, visto ser estes de domínio da medicina. Crenças e rituais fortalecem tais ideais, servindo como modelos culturais para a futura mulher-mãe. O momento do nascimento é envolto pelo discurso do medo e do risco, reforçando a necessidade do saber médico e a incompetência feminina para viver o parto. Durante o puerpério a mulher vivencia o processo de “tornar-se mulher-mãe”, questionando sobre seus ideais de maternidade e vivendo uma ambivalência de sentimentos, o que a fragiliza, tornando-a sensível à opiniões, intromissões e modulações culturais e sociais. Por fim, identificam-se trajetórias de atenção marcadas pela violência física e emocional no subsetor suplementar, levantando questionamentos sobre a qualidade da assistência ofertada às suas usuárias. A partir disso tudo, fica a compreensão que as mulheres, moduladas por saberes biomédicos caminham por trajetórias semelhantes na saúde suplementar, por caminhos que desapropriam-nas de seu corpo e de suas escolhas, experenciando momentos de desrespeito e violência. No entanto, ainda existem movimentos de resistência, trajetórias de fuga, as quais possibilitam, não sem sofrimento, a vivência de gestar e parir que elas desejam. É preciso urgentemente atentar para como está ocorrendo a atenção obstétrica no subsetor suplementar, para além dos percentuais de cesariana, os quais são apenas o desfecho esperado de uma gestação modulada, invadida e culturalmente medicalizada. / This study aimed to analyze the construction of a cultural representation of women's inability to gestate and give birth through the analysis of care trajectories of women assisted by the supplemental subsector of healthcare in Porto Alegre, RS. It sought to question the social and cultural context of the experience of pregnancy and delivery of women attended by health plans or insurances, including pregnancy and birth as cultural processes, inserted in contemporary times. For that purpose, an ethnographic study was performed from April to November 2014 in the city of Porto Alegre, RS, with the participation of eight pregnant women, attended by health plans and who were with more than 32 weeks of pregnancy. Data were produced through participant observation, field diary notes and semi-structured interviews, which were recorded and fully transcribed. The analytical process was guided by the interpretive anthropology, based on the theoretical framework of Clifford Geertz on culture. It was possible to capture the healthcare trajectories of the women, drawing modulation and resistance paths. Also, complex and subjective views about pregnancy and delivery were internalized, and they were always understood in the midst of the culture in which women lived and experienced such processes. Social networks are presented as modulator elements on the ideals of motherhood and childbirth choices. Pregnancy is comprised of a medicalized look, guiding to the idea that women should not be involved with pregnancy and childbirth, given they’re both of medicine domain. Beliefs and rituals strengthen these ideals, serving as cultural models for the future mother-woman. The moment of birth is surrounded by the discourse of fear and risk, stressing the need for medical knowledge and women's inability for living the parturition. During puerperium women go through the process of "becoming a mother-woman", questioning their ideals of motherhood and living an ambivalence of feelings, which weakens themselves, making them sensitive to opinions, intrusions and cultural and social modulations. Finally, care trajectories marked by physical and emotional violence are identified in the supplemental subsector, raising questions about the quality of assistance given to its users. From all this is the understanding that women, modulated by biomedical knowledge go through similar paths in the supplemental health, by ways that evict them from their bodies and their choices, experiencing moments of disrespect and violence. However, there still are movements of resistance, escape paths, which enable, not without suffering, the experience of gestating and giving birth that they want. It is urgent to pay attention to how the obstetric care in the supplemental subsector is happening, beyond Cesarean percentage, which is only the outcome expected from a modulated pregnancy, invaded and culturally medicalized. / Este trabajo tuvo como objetivo analizar la construcción de una representación cultural sobre la incompetencia femenina para gestar y parir por medio del análisis de las trayectorias asistenciales de mujeres atendidas en el subsector suplementar de atención a la salud de Porto Alegre, RS. Se buscó problematizar el contexto social y cultural de vivencia de la gestación y del parto de las mujeres atendidas por planes o seguros salud, comprendiendo la gestación y el nacimiento como procesos culturales e inseridos en la contemporaneidad. Para tanto, fue realizado un estudio etnográfico de abril a noviembre de 2014 en la ciudad de Porto Alegre, RS, con la participación de ocho mujeres embarazadas, atendidas por planes de salud y que estaban con más de 32 semanas de gestación. Los datos fueron producidos por medio de observación participante, anotaciones en diario de campo y entrevistas semi estructuradas, las cuales fueron grabadas y transcriptas a la íntegra. El proceso analítico fue orientado por la antropología interpretativa, teniendo como base el referencial teórico sobre Cultura de Clifford Geertz. Fue posible comprender las trayectorias asistenciales de las mujeres acompañadas, dibujando caminos de modulación y resistencia. Fueron tomadas visiones complejas y subjetivas sobre la gestación y el parto, siempre comprendidas en el medio a la cultura en que las mujeres vivían y experienciaban estos procesos. Las redes sociales se presentan como elementos moduladores sobre los ideales de maternidad y elección del parto. La gestación es comprendida por una mirada medicalizada, orientada a la idea de que la mujer no debe preocuparse con el embarazo y el parto, vistoéstos de dominio de la medicina. Creencias y rituales fortalecen tales ideales, sirviendo como modelos culturales para la futura mujer-madre. El momento del nacimiento es tomado por el discurso del miedo y del riesgo, reforzando la necesidad del saber médico yla incompetencia femenina para vivir el parto. Durante el puerperio la mujer experimenta el proceso de “convertirse mujer-madre”, cuestionando sobre sus ideales de maternidad y viviendo una ambivalencia de sentimientos, lo que la fragiliza, la convirtiendo sensible a opiniones, intromisiones y modulaciones culturales y sociales. Por fin, se identifican trayectorias de atención marcadas por la violencia física y emocional en el subsector suplementar, levantando cuestionamientos sobre la cualidad de la asistencia ofertada a sus usuarias. Con eso, quedala comprensión de que las mujeres, moduladas por saberes biomédicos, caminan por trayectorias semejantes en la salud suplementar, por caminos que las desapropian de su cuerpo y de sus elecciones, experienciando momentos de falta de respeto y violencia. Sin embargo, todavía existen movimientos de resistencia, trayectorias de fuga, las cuales posibilitan, no sin sufrimiento, la vivencia de gestar y parir que ellas desean. Es necesario urgentemente atentar para cómo está ocurriendo la atención obstétrica en el subsector suplementar, para más allá de los porcentuales de cesariana, los cuales son apenas el desfecho esperado de una gestación modulada, invadida y culturalmente medicalizada.

O peso de nascimento tem importante relação com a sobrevivência infantil, pois recém-nascidos com baixo peso – BPN (até 2.500 gramas) apresentam maior morbimortalidade no primeiro ano de vida e, além disso, repercussões importantes na sua saúde quando adultos. O presente estudo investigou o impacto de fatores determinantes biológicos, assistenciais e demográficos, sobre a prevalência do BPN e sua evolução temporal no Brasil. Este é um estudo de séries temporais, baseado no registro dos nascidos vivos das vinte e sete capitais das cinco regiões brasileiras de acordo com a residência materna e o local de ocorrência do parto, obtidos por intermédio do Sistema Nacional de Nascidos Vivos (SINASC) no período de 1996 a 2011. As taxas de BPN, as variáveis idade e escolaridade materna, pré-natal, idade gestacional e tipo de parto foram analisadas pelo teste de qui-quadrado de tendência. A estimativa da proporção de casos que poderiam ser evitados de acordo com cada estrato das variáveis foi calculado de acordo com a Fração Atribuível Populacional (FAP). O impacto desses fatores determinantes na tendência do BPN, incluindo a variável ano de nascimento, foi verificado num modelo sequencial ajustado por intermédio da Regressão de Poisson. Foram incluídos no estudo 11.200.255 recém-nascidos únicos com peso igual ou superior a 500 gramas. Diminuiu o número de nascimentos em todo país, e a prevalência média da taxa de BPN manteve-se em torno de 8%. A proporção de gestações na adolescência diminuiu em todas as regiões, no Brasil, de acordo com as capitais, passou de 10,1% em 1996 para 8,1% em 2011, enquanto para mulheres acima de 35 anos aumentou de 8,0% em 1996 para 13,1% em 2011. Os extremos da idade materna mostraram um efeito significativo sobre o BPN. Houve aumento da escolaridade materna, da cobertura de pré-natal, de cesarianas e de partos prematuros, sobretudo nas regiões Sudeste e Sul, as mais desenvolvidas. Nas capitais brasileiras durante o período, diminuiu 33,1% o percentual de mães com menos de oito anos de estudo; aumentou 7,6% a proporção de mães que realizaram sete ou mais consultas de pré-natal; aumentou 4,4% o percentual de nascimentos prematuros e 12,2% o percentual de cesarianas. Houve maior risco para o BPN entre gestantes adolescentes, mulheres de baixa escolaridade, entre àquelas que realizaram um pré-natal incompleto, entre os recém-nascidos pré-termo, e, nas regiões Sudeste e Sul, o parto cesáreo foi fator de exposição para o BPN. Quando a variável ano de nascimento foi ajustada aos fatores determinantes, a idade materna mostrou um impacto anual de 0,2% sobre o BPN e o tipo de parto 0,3%. Comparativamente à idade materna, a escolaridade materna e a cobertura de pré-natal apresentaram um impacto quatro e cinco vezes maiores, respectivamente, sobre o BPN no período, indicando o fator protetor dessas variáveis. Os resultados do estudo demonstram uma melhora na assistência pré-natal no Brasil com repercussões favoráveis em relação ao peso de nascimento. Em contrapartida, o aumento do número de partos operatórios e prematuros torna-se uma preocupação crescente contribuindo positivamente para a manutenção das taxas de baixo peso ao nascer no país. Nessa perspectiva, torna-se necessária a elaboração de políticas efetivas em saúde que contribuam para uma assistência pré-natal mais acessível e qualificada e a execução de ações intersetoriais como, por exemplo, uma melhor rede pública de ensino no país, que permitam um acesso universal. / The birth weight has an important relation with the children survival thus newborns with low birth weight – LBW (till 2,500 grams) show a higher morbimortality in the first year of life and, in addition, substantial effects on health in adulthood. The present study investigated the impact of biological, assistencial and demographic determinant factors over the prevalence of LBW and its temporal evolution in Brazil. This is a time series study, based on the record of live births of the twenty-seven capitals from five Brazilian regions according to maternal residence and the birth place, obtained through the National System of Live Born (SINASC) from 1996 to 2011. The rates of low birth weight, age and maternal schooling, prenatal care, gestational age and type of delivery were analyzed by the chi-square test of trend. The estimation of the cases proportion that could be avoided according to each stratum of the variables was calculated according to the Population Attributable Fraction (PAF). The impact of these determinant factors in the trend of BPN, including the variable year of birth, was verified at a sequential model adjusted through the Poisson Regression. It was included at the study 11.200.255 single newborns that had their birth weight equal or greater than 500 grams. It diminished the number of newborn in all the country and the prevalence average of LBW rate kept 8.0%. The proportion of teenage pregnancies diminished in all the regions in Brazil, and according to the capitals, decreased from 10.1% in 1996 to 8.1% in 2011, while that for women over 35 years increased from 8, 0% in 1996 to 13.1% in 2011. The extremes of maternal age showed a signigicant effect on LBW. There was an increase in maternal schooling, coverage of prenatal care, cesarean section and premature births, mainly in the South and Southeast that more developed. In Brazilian capitals during the period, 33.1% decreased the percentage of mothers with less than eight years of study; increased 7.6% the proportion of mothers who had seven or more prenatal appointments; increased 4.4% the percentage of premature births and 12.2% the percentage of cesarean. There was a higher risk for LBW among pregnant adolescents, low schooling mothers, mothers with an incomplete prenatal, pre-term newborns and in the Southeast and South regions, the cesarean section was the exposition factors for LBW. When the variable year of birth was fitted for the determinant factors, the maternal age showed an annual impact of 0.2% on LBW and the type of delivery 0.3%. Comparatively to the maternal age, the maternal schooling and the prenatal coverage had an impact four and five times higher, respectively, on LBW in the period, indicating the protective factor of these variables. The study results demonstrate an improvement at the prenatal care assistance in Brazil with favorable repercussions in relation to birth weight. In contrast, the increase in the number of cesarean section and premature births become a growing concern contributing positively to the maintenance of LBW rates in the country. From this perspective, it becomes necessary the elaboration of policies in effective health that contribute for a more affordable and qualified prenatal assistance and implementation of inter-sectorial actions, for example, a better public school teaching in the country that enable a universal access.