The ethical and practical issues of obtaining a blood sample pose a significant challenge to performing pharmacokinetic studies in children, infants and neonates. Dried blood spot analysis, based on the collection of a micro blood sample has potential to overcome these difficulties. There are at present a limited number of reports on the utility of dried blood spot analysis in clinical pharmacokinetic studies. The studies described in this thesis were undertaken to investigate the accuracy and precision of dried blood spot sampling coupled with mass spectrometry detection for drug quantification, and clinically validate the robustness and feasibility of this technique for pharmacokinetic studies in preterm neonates. Dried blood spot methods were developed for application to pharmacokinetic studies of test drugs dexamethasone and caffeine. Investigations were focused on the blood collection system, analyte recovery and optimisation of the detection system. In-vitro validation results indicated developed methods were precise, accurate and selective in accordance with the Food and Drug Administration regulatory guidelines on the assessment of bioanalytical methods. Results were not significantly affected by small variations in the blood volume spotted or the presence of petroleum jelly, which is often used on the sampling site during capillary blood collection in neonates. Variability in haematocrit was determined to be the single most important factor affecting assay accuracy. Stability assessments by comparison with freshly prepared samples verified the suitability of sample drying, storage and post sample extraction conditions. An investigation of method transferability between different analytical instruments was undertaken with caffeine to provide an assessment of the robustness of dried blood spot analysis. Results generated from a single and triple quadrupole mass spectrometer were comparable with an expected lower limit of quantification with the latter technique most likely due to a greater ionisation and detection efficiency. Intravenous dexamethasone pharmacokinetics was determined in 5 preterm neonates receiving treatment for chronic lung disease. Individual pharmacokinetic analyses were performed using a one compartment model to estimate primary pharmacokinetic parameters, clearance (mean, 0.18 l/h/kg) and volume of distribution (mean, 1.33 l/kg). The whole blood derived mean estimates were similar to previous plasma clearance and volume estimates of 0.14 l/h/kg and 1.91 l/kg, respectively reported in neonates (n=7). This highlights the potential for dried blood spot analysis as an alternative to conventional plasma based methods for dexamethasone dose optimisation studies in neonates. The population pharmacokinetics of oral / intravenous caffeine was determined in 67 preterm neonates. A one compartment model was used to describe the blood concentration-time data. Model evaluation using a bootstrapping technique confirmed the robustness and stability of the developed model. Pharmacokinetic parameters derived from dried blood spot drug measurements were estimated with precision (relative standard error < 10%) and were comparable to estimates of plasma clearance (mean, 7.3 vs. 7.0 ml/h/kg) and volume of distribution (mean, 593 vs. 851 ml/kg) from a previous population study in neonates (n=110). Weight and postnatal age were the most influential covariates in the clearance model which is in agreement with previous population studies. These results demonstrate that dried blood spot analysis is a practical technique, with significant potential as a robust method for use in clinical pharmacokinetic studies in vulnerable populations such as preterms. Haematocrit related effects on paper will need to be accounted for if this potential is to be realised. Further investigations to determine the reproducibility of capillary blood sampling in neonates and the impact of using blood drug measurements on pharmacokinetic parameter estimation will be necessary before widespread use of the technique is possible.

There are different opinions on who the appropriate decision makers are for extremely premature infants. Some argue the responsibility should fall to the parents, and others argue the neonatal experts should be responsible for decision making. This study explored parental perceptions of their involvement in decision making in the neonatal intensive care (NICU). The NICU operated from the philosophy of Family Centered Care (FCC). FCC situates the parents as central to all aspects of their child’s care and as such, the parents should be well informed and actively involved in decision making. An interpretative descriptive approach was used to examine the experiences of seven parents who had infants born at 24-26 weeks gestation who were admitted to the NICU. Thematic analysis revealed that the culture of the NICU along with the relationships developed in the NICU had an impact on the parents’ perceptions of decision making.

<p>This dissertation recruited 24 premature infants born less than 32 weeks gestational age over a one year time period from October 2010 to 2011. The goals were to longitudinally measure cerebral oxygen saturation, evaluate how environmental variables controlled by nursing, positioning and noise, affect cerebral oxygen saturations, and examine the relationship between cerebral oxygen saturation and two currently measured vital signs.</p><p>Using mixed general linear models, findings from this dissertation showed the developmental trajectory of cerebral oxygen saturation values in premature infants' began in the high 70s during the first two days of life and then significantly decreased into the mid-60s over several weeks during hospitalization in a neonatal intensive care unit (NICU). The trajectory of cerebral oxygen saturation during the first week of life in those infants who developed an IVH did not significantly differ from those infants without IVH. At this time, use of cerebral oxygen saturation to identify those infants at risk for IVH during the first week of life cannot be supported, but findings may indicate that cerebral oxygen saturation monitoring could potentially monitor the severity of the impact of IVH later during hospitalization as those infants with an IVH had significantly lower cerebral oxygen saturation values after the third week of life. In this case, cerebral oxygen saturation might help to understand the long-term degree of neurological damage. </p><p>Heart rate and peripheral oxygenation were chosen as the two physiologic variables to compare to cerebral oxygen saturation and average cerebral oxygen saturation was lower with higher heart rate and higher with higher peripheral oxygenation. Peripheral oxygenation that is already routinely measured in premature infants appears to not provide an accurate measure of the changes in cerebral oxygen saturation. Cerebral oxygen saturation monitoring is highly suggested for those infants who are at risk for neurological damage such as infants with hypoxic-ischemic encephalopathy or seizures since peripheral oxygenation does not appear to be an appropriate proxy for cerebral oxygenation.</p><p>Finally, sound and positioning were chosen to represent two frequently encountered components of the neonatal intensive care environment that also influence infant cerebral oxygen saturation. A peak in sound from the ambient sound level was only 5 decibels and found to not significantly affect cerebral oxygen saturation values. A neutral position considered the gold standard-- supine, head midline--was compared to five other positions widely used by NICU nurses. However, results showed positions with a turned head did not significantly change cerebral oxygen saturation from the neutral position. Yet, differences in cerebral oxygen saturation were found between two lateral positions (left lateral and right lateral, head elevated 15°) with an elevated head measuring lower cerebral oxygen saturation levels.</p> / Dissertation

No description available.

Caffeine has calciuric and osteoclasteogenesis effects. Objectives: To examine the association of caffeine cumulative dose and duration of therapy and the Osteopenia of prematurity (OP) Study design: A retrospective observational cohort study included premature infants less than 31 weeks and birth weight less than 1500 grams. OP was evaluated using chest X-rays on biweekly basis over 12 weeks hospital stay. Caffeine cumulative dose and duration of therapy, steroid dose and diuretic dose along with other maternal and neonatal risk factors were collected to examine their impact on OP. Results: The cohort included 109 infants. 51% had OP and 8% had spontaneous rib fractures. Using the generalized mixed model, Caffeine dose and duration of caffeine displayed strong association with OP. Steroids and vitamin D had significant correlation with OP while diuretic use did not show statistical significant effect. Conclusion: Caffeine cumulative dose and duration of therapy are associated with OP.

The splanchnic bed is a group of organs (liver, intestines, stomach, pancreas and spleen) which are active in the metabolism of amino acids. However, the impact of this group of organs on the dietary requirements of humans has yet to be determined. The focus of this research will be the requirements of two indispensable amino acids, threonine and lysine, and the impact of the splanchnic bed on amino acid kinetics. Threonine is an indispensable amino acid which is critical in the production of mucins in the gut and contributes significantly to collagen, elastin and tooth enamel formation in mammals. The first study was designed to determine the threonine requirement for the parenterally-fed, stable, post-surgical neonate. The mean threonine parenteral requirement, as experimentally derived in human neonates, was 32.8 mg•kg-1•d-1 which was less than the recommended enteral intake of 76 mg•kg-1•d-1 suggesting a splanchnic uptake in humans of 57%. Lysine is an indispensable amino acid used primarily, in the mammalian body, for protein synthesis but it also acts as a precursor for carnitine synthesis. The second study was devised to determine the lysine requirement for the parenterally-fed, stable, post-surgical neonate. The mean lysine parenteral neonatal requirement as experimentally determined in human neonates, was 104.9 mg•kg-1•d-1 which was less than the recommended enteral intake of 119 mg•kg-1•d-1 suggesting a splanchnic uptake in humans of 12%. The third study was intended to increase our knowledge of the metabolism of threonine and lysine by the splanchnic bed. Adult humans were fed isotopic threonine and lysine both enterally and parenterally. We determined that retention of threonine and lysine by the splanchnic bed was 16.7% and 17.1% respectively, which were not significantly different. The conclusion was that, in healthy human adult males, there was no difference in the extraction of threonine and lysine by the splanchnic bed which was different from our findings in parenterally fed piglets and human neonates.

The splanchnic bed is a group of organs (liver, intestines, stomach, pancreas and spleen) which are active in the metabolism of amino acids. However, the impact of this group of organs on the dietary requirements of humans has yet to be determined. The focus of this research will be the requirements of two indispensable amino acids, threonine and lysine, and the impact of the splanchnic bed on amino acid kinetics. Threonine is an indispensable amino acid which is critical in the production of mucins in the gut and contributes significantly to collagen, elastin and tooth enamel formation in mammals. The first study was designed to determine the threonine requirement for the parenterally-fed, stable, post-surgical neonate. The mean threonine parenteral requirement, as experimentally derived in human neonates, was 32.8 mg•kg-1•d-1 which was less than the recommended enteral intake of 76 mg•kg-1•d-1 suggesting a splanchnic uptake in humans of 57%. Lysine is an indispensable amino acid used primarily, in the mammalian body, for protein synthesis but it also acts as a precursor for carnitine synthesis. The second study was devised to determine the lysine requirement for the parenterally-fed, stable, post-surgical neonate. The mean lysine parenteral neonatal requirement as experimentally determined in human neonates, was 104.9 mg•kg-1•d-1 which was less than the recommended enteral intake of 119 mg•kg-1•d-1 suggesting a splanchnic uptake in humans of 12%. The third study was intended to increase our knowledge of the metabolism of threonine and lysine by the splanchnic bed. Adult humans were fed isotopic threonine and lysine both enterally and parenterally. We determined that retention of threonine and lysine by the splanchnic bed was 16.7% and 17.1% respectively, which were not significantly different. The conclusion was that, in healthy human adult males, there was no difference in the extraction of threonine and lysine by the splanchnic bed which was different from our findings in parenterally fed piglets and human neonates.

Prenatal methamphetamine exposure is associated with functional and neurostructural alterations, but neuroimaging investigations of these effects in infants are almost non-existent. Studies in neonates permit a degree of separation of drug exposure effects from potential confounders in the postnatal environment. Magnetic resonance imaging (MRI) was used to investigate the neurostructural effects of prenatal methamphetamine exposure on neonates recruited from a Cape Town community. Mothers were recruited during pregnancy and interviewed regarding methamphetamine use. Women in the exposure group used methamphetamine at least twice per month during pregnancy, while control mothers did not use methamphetamine. MRI scans were acquired within the first postnatal month. Anatomical images were processed using FreeSurfer and subcortical and cerebellar structures manually segmented with Freeview. Volumes were regressed with methamphetamine exposure (days/month of pregnancy) and related confounding variables, including total brain volume, gestational age at scan, exposure to cigarette smoking and infant sex. Diffusion data were processed with FSL, and diffusion tensors and tensor parameters determined using AFNI. Probabilistic tractography defined white matter connections between target regions. For the first analysis, five major white matter networks (commissural, and bilateral projection and association networks) were defined between spherical targets. For the second analysis, regions traced in the anatomical study were used as targets. Averaged DTI parameters were then calculated for each connection, and multiple regression analysis determined associations between DTI parameters and methamphetamine exposure at network level and in the individual connections. Methamphetamine exposure was associated with reduced caudate nucleus volume bilaterally, and in the right caudate following adjustment for confounders. Exposure was associated with reduced fractional anisotropy in all major white matter networks, and in individual connections within the limbic meso-cortico-striatal circuit. Exposure was associated with increased radial diffusivity in a subset of these. These results support findings in older children of methamphetamine-induced neurostructural damage, and demonstrate that such effects are already measurable in neonates. Corticostriatal circuit changes may underlie the impaired executive function observed in prenatally exposed children, and suggest a specific mechanism of damage in dopaminergic-related circuits that is consistent with the neurotoxic actions of methamphetamine.

O final do período gestacional é marcado por importantes processos que caracterizam a maturação pulmonar fetal, dentre os quais destacam-se alterações estruturais, como a expansão das áreas de troca gasosa; e funcionais, tais como o aumento na produção de surfactante, cuja principal função é reduzir a tensão superficial na interface ar-líquido alveolar, evitando o colapso dos alvéolos na fase final da expiração. Estudos realizados em diferentes espécies animais indicam a influência de fatores endócrinos, incluindo os glicocorticóides, no desenvolvimento pulmonar fetal e transição para a vida extra-uterina. Até o momento, não há estudos na espécie canina, com o objetivo primordial de avaliar a ação da corticoterapia materna na melhora da função pulmonar. Desta forma, são objetivos deste estudo identificar as alterações morfométricas e funcionais pulmonares de neonatos pré-termos e termos submetidos à corticoterapia materna pré-natal e correlacioná-las à melhora da função pulmonar no período neonatal. Para tanto, 25 neonatos da espécie canina, nascidos por cesariana programada, foram alocados aleatoriamente em 2 grupos: Grupo Controle (CONT) (sem corticoterapia materna; n=15) e Grupo Betametasona (BETA) (corticoterapia materna aos 55 dias de gestação; n=10), por aplicação de betametasona (Celestone Soluspan®) em dose única de 0,5 mg/Kg de peso materno, por via de administração intra muscular (IM). No grupo Controle, os neonatos foram avaliados aos 55, 57 e 63 dias de gestação, enquanto no Grupo Betametasona, aos 57 e 58 dias de gestação. Perfez-se a avaliação clínica por escore Apgar, hemogasometria e radiografia pulmonar. Ainda, as modificações pulmonares estruturais e funcionais foram verificadas por análise morfométrica e imunoistoquímica para detecção do número de pneumócitos tipo II produtores da proteína B do surfactante (SP-B) no parênquima pulmonar. Houve melhor evolução clínica nos neonatos pertencentes ao grupo BETA 57 já aos 60 minutos de vida. Os valores de freqüência cardíaca foram estatisticamente maiores nos grupos tratados e controle termo, em comparação ao grupo CONT 57. O escore de freqüência e padrão respiratórios foi estatisticamente superior nos grupos BETA 57 e CONT 63, seguido pelo grupo BETA 58. Valores estatisticamente semelhantes de irritabilidade reflexa foram observados entre os grupos tratados e termo. Do nascimento aos 60 minutos de vida não houve diferença estatística na avaliação do tônus muscular entre os grupos, com valores significativamente superiores aos 240 minutos de vida nos grupos tratados e controle termo. Os neonatos do grupo CONT 63 apresentaram escore de mucosas aparentes da avaliação Apgar estatisticamente superior em relação aos demais grupos ao nascimento, com valores estatisticamente iguais aos grupos tradados e CONT 57 aos 60 minutos de vida. Ao nascimento e após 2 horas de vida, todos os neonatos apresentaram acidemia, com melhor resposta compensatória ao desequilíbrio ácido-básico no grupo BETA 58. Houve maior septação nos grupos tratados e controle termo, em relação aos demais grupos. Um percentual estatisticamente superior de alveolização foi observado no grupo CONT 63, seguido pelo grupo BETA 58. Um menor percentual de sáculos foi identificado no grupo CONT 63 seguido pelos grupos BETA 57 e CONT 55. Não evidenciou-se diferença estatística quanto ao número de pneumócitos tipo II marcados para a proteína SP-B entre os grupos tratados e CONT 57. A avaliação radiográfica mostrou menor percentual de broncograma aéreo, bem como áreas de atelectasia, no grupo BETA 57, associado à melhor visualização do parênquima pulmonar. Em conclusão, a administração de betametasona materna no período pré-natal induz alterações estruturais do parênquima pulmonar, resultando em melhores valores de escore Apgar. Houve melhor resposta compensatória nos grupos tratados, reflexa ao aumento da capacidade de troca gasosa pulmonar. Não foi possível identificar aumento na síntese de surfactante pulmonar entre os grupos, em resposta à administração pré-natal de betametasona. / The final gestational period is marked by an important processes that characterize the lung fetal maturation, like structural changes such as expansion of the areas of gas exchange, and functional changes, such as increased production of surfactant, whose main function is to reduce the surface tension in the air-liquid interface alveolar, preventing the alveoli from collapsing during late expiration. Studies in different species indicate the influence of endocrine factors, including glucocorticoids in fetal lung development and transition to extrauterine life. Up till now, there is not studies in dogs, with the primary objective to evaluate the action of maternal corticosteroid therapy in improving lung function. Thus, the objectives of this study was to identify morphological changes in lung function in preterm and terms neonates submitted to prenatal maternal corticosteroids and correlate them to the improvement in lung function during the neonatal period. For it 25 canine neonates, born by scheduled cesarean section, were randomly divided into 2 groups: control group (CONT) (no maternal corticosteroid therapy, n = 15) and Group betamethasone (BETA) (maternal corticosteroid therapy at 55 days gestation; n = 10), by application of betamethasone (Celestone Chronodose Injection ®) in a single dose of 0.5 mg / kg of maternal weight, route of administration by intra-muscular (IM). Control group neonates were evaluated at 55, 57 and 63 days of gestation, and the betamethasone group, at 58 and 57 days of gestation. The clinical assessment was made by Apgar score, blood gas and pulmonary radiography. Still, the structural and functional lung changes were verified by morphometric analysis and immunohistochemistry to detect the number of type II pneumocytes producers surfactant protein B (SP-B) in the lung parenchyma. There was better clinical outcome in the groups BETA 57 at 60 minutes of life. The values of heart rate were significantly higher in term treatment and control groups compared to the group CONT 57. The score of respiratory frequency and pattern was statistically higher in groups BETA 57 e 63 followed by the group BETA 58. Statistically similar reflex irritability were observed between the treated groups and term. From birth to 60 minutes of life there was not statistical difference in the assessment of muscle tone between the groups, with significantly higher values at 240 minutes of life in term treatment and control groups. Neonates of CONT 63 has mucous apparent assessment of Apgar statistically superior to other groups at birth, with values statistically equal to tratads and group CONT 57 at 60 minutes of life. At birth and after 2 hours of life, all neonates had acidemia, with better compensatory response to acid-base balance in the group BETA 58. There was an increased septation in treated and control groups comparing other groups. A statistically higher percentage of alveolarization was observed in group CONT 63, followed by the group BETA 58. A lower percentage of saccules was identified in the group CONT 63 followed by groups BETA 57 and CONT 55. There was not statistical differences in the number of type II pneumocytes marked for protein SP-B between the treated groups and CONT 57. The radiographic evaluation showed a lower percentage of air bronchogram, and atelectasis in the group BETA 57, associated with better visualization of the pulmonary parenchyma. In conclusion, maternal administration of betamethasone in prenatally period induced structural changes of the lung parenchyma, resulting in higher values of Apgar score. There was greater compensatory response in the treated groups, the reflex of an increase capacity of pulmonary gas exchange. It was not possible to indentify increases synthesis of surfactant between the groups in response to prenatal administration of betamethasone.

O final do período gestacional é marcado por importantes processos que caracterizam a maturação pulmonar fetal, dentre os quais destacam-se alterações estruturais, como a expansão das áreas de troca gasosa; e funcionais, tais como o aumento na produção de surfactante, cuja principal função é reduzir a tensão superficial na interface ar-líquido alveolar, evitando o colapso dos alvéolos na fase final da expiração. Estudos realizados em diferentes espécies animais indicam a influência de fatores endócrinos, incluindo os glicocorticóides, no desenvolvimento pulmonar fetal e transição para a vida extra-uterina. Até o momento, não há estudos na espécie canina, com o objetivo primordial de avaliar a ação da corticoterapia materna na melhora da função pulmonar. Desta forma, são objetivos deste estudo identificar as alterações morfométricas e funcionais pulmonares de neonatos pré-termos e termos submetidos à corticoterapia materna pré-natal e correlacioná-las à melhora da função pulmonar no período neonatal. Para tanto, 25 neonatos da espécie canina, nascidos por cesariana programada, foram alocados aleatoriamente em 2 grupos: Grupo Controle (CONT) (sem corticoterapia materna; n=15) e Grupo Betametasona (BETA) (corticoterapia materna aos 55 dias de gestação; n=10), por aplicação de betametasona (Celestone Soluspan®) em dose única de 0,5 mg/Kg de peso materno, por via de administração intra muscular (IM). No grupo Controle, os neonatos foram avaliados aos 55, 57 e 63 dias de gestação, enquanto no Grupo Betametasona, aos 57 e 58 dias de gestação. Perfez-se a avaliação clínica por escore Apgar, hemogasometria e radiografia pulmonar. Ainda, as modificações pulmonares estruturais e funcionais foram verificadas por análise morfométrica e imunoistoquímica para detecção do número de pneumócitos tipo II produtores da proteína B do surfactante (SP-B) no parênquima pulmonar. Houve melhor evolução clínica nos neonatos pertencentes ao grupo BETA 57 já aos 60 minutos de vida. Os valores de freqüência cardíaca foram estatisticamente maiores nos grupos tratados e controle termo, em comparação ao grupo CONT 57. O escore de freqüência e padrão respiratórios foi estatisticamente superior nos grupos BETA 57 e CONT 63, seguido pelo grupo BETA 58. Valores estatisticamente semelhantes de irritabilidade reflexa foram observados entre os grupos tratados e termo. Do nascimento aos 60 minutos de vida não houve diferença estatística na avaliação do tônus muscular entre os grupos, com valores significativamente superiores aos 240 minutos de vida nos grupos tratados e controle termo. Os neonatos do grupo CONT 63 apresentaram escore de mucosas aparentes da avaliação Apgar estatisticamente superior em relação aos demais grupos ao nascimento, com valores estatisticamente iguais aos grupos tradados e CONT 57 aos 60 minutos de vida. Ao nascimento e após 2 horas de vida, todos os neonatos apresentaram acidemia, com melhor resposta compensatória ao desequilíbrio ácido-básico no grupo BETA 58. Houve maior septação nos grupos tratados e controle termo, em relação aos demais grupos. Um percentual estatisticamente superior de alveolização foi observado no grupo CONT 63, seguido pelo grupo BETA 58. Um menor percentual de sáculos foi identificado no grupo CONT 63 seguido pelos grupos BETA 57 e CONT 55. Não evidenciou-se diferença estatística quanto ao número de pneumócitos tipo II marcados para a proteína SP-B entre os grupos tratados e CONT 57. A avaliação radiográfica mostrou menor percentual de broncograma aéreo, bem como áreas de atelectasia, no grupo BETA 57, associado à melhor visualização do parênquima pulmonar. Em conclusão, a administração de betametasona materna no período pré-natal induz alterações estruturais do parênquima pulmonar, resultando em melhores valores de escore Apgar. Houve melhor resposta compensatória nos grupos tratados, reflexa ao aumento da capacidade de troca gasosa pulmonar. Não foi possível identificar aumento na síntese de surfactante pulmonar entre os grupos, em resposta à administração pré-natal de betametasona. / The final gestational period is marked by an important processes that characterize the lung fetal maturation, like structural changes such as expansion of the areas of gas exchange, and functional changes, such as increased production of surfactant, whose main function is to reduce the surface tension in the air-liquid interface alveolar, preventing the alveoli from collapsing during late expiration. Studies in different species indicate the influence of endocrine factors, including glucocorticoids in fetal lung development and transition to extrauterine life. Up till now, there is not studies in dogs, with the primary objective to evaluate the action of maternal corticosteroid therapy in improving lung function. Thus, the objectives of this study was to identify morphological changes in lung function in preterm and terms neonates submitted to prenatal maternal corticosteroids and correlate them to the improvement in lung function during the neonatal period. For it 25 canine neonates, born by scheduled cesarean section, were randomly divided into 2 groups: control group (CONT) (no maternal corticosteroid therapy, n = 15) and Group betamethasone (BETA) (maternal corticosteroid therapy at 55 days gestation; n = 10), by application of betamethasone (Celestone Chronodose Injection ®) in a single dose of 0.5 mg / kg of maternal weight, route of administration by intra-muscular (IM). Control group neonates were evaluated at 55, 57 and 63 days of gestation, and the betamethasone group, at 58 and 57 days of gestation. The clinical assessment was made by Apgar score, blood gas and pulmonary radiography. Still, the structural and functional lung changes were verified by morphometric analysis and immunohistochemistry to detect the number of type II pneumocytes producers surfactant protein B (SP-B) in the lung parenchyma. There was better clinical outcome in the groups BETA 57 at 60 minutes of life. The values of heart rate were significantly higher in term treatment and control groups compared to the group CONT 57. The score of respiratory frequency and pattern was statistically higher in groups BETA 57 e 63 followed by the group BETA 58. Statistically similar reflex irritability were observed between the treated groups and term. From birth to 60 minutes of life there was not statistical difference in the assessment of muscle tone between the groups, with significantly higher values at 240 minutes of life in term treatment and control groups. Neonates of CONT 63 has mucous apparent assessment of Apgar statistically superior to other groups at birth, with values statistically equal to tratads and group CONT 57 at 60 minutes of life. At birth and after 2 hours of life, all neonates had acidemia, with better compensatory response to acid-base balance in the group BETA 58. There was an increased septation in treated and control groups comparing other groups. A statistically higher percentage of alveolarization was observed in group CONT 63, followed by the group BETA 58. A lower percentage of saccules was identified in the group CONT 63 followed by groups BETA 57 and CONT 55. There was not statistical differences in the number of type II pneumocytes marked for protein SP-B between the treated groups and CONT 57. The radiographic evaluation showed a lower percentage of air bronchogram, and atelectasis in the group BETA 57, associated with better visualization of the pulmonary parenchyma. In conclusion, maternal administration of betamethasone in prenatally period induced structural changes of the lung parenchyma, resulting in higher values of Apgar score. There was greater compensatory response in the treated groups, the reflex of an increase capacity of pulmonary gas exchange. It was not possible to indentify increases synthesis of surfactant between the groups in response to prenatal administration of betamethasone.