RESUMO
Objectives: Through a systematic review and meta-analysis of the literature we aimed to compare the levels of BDNF, NGF, NT-3, NT-4, and GDNF between human term and preterm infants, and investigate factors implicated in the variability of effect size estimates. Methods: The analysis was performed in three online databases, MEDLINE Complete, PsycINFO, and CINAHL. A random effects model was used to calculate the standardized mean difference (SMD) of neurotrophic factor levels in preterm infants vs. term within a 95% confidence interval (CI). To explore sources of heterogeneity meta-regression models were implemented. Results: Sixteen studies were included in this meta-analysis. A combined sample of 1,379 preterm and 1,286 term newborns were evaluated. We identified significant lower BDNF (SMD = -0.32; 95% CI: -0.59, -0.06; p = 0.014) and NT-3 (SMD = -0.31; 95% CI: -0.52, -0.09; p = 0.004) levels in preterm compared to term infants. No significant difference was observed in NGF and NT-4 levels between groups. Given that only two effect sizes were generated for GDNF levels, no meta-analytical model was performed. Meta-regression models revealed sample type (placental tissue, cerebrospinal fluid, peripheral blood, and umbilical cord blood) as a significant moderator of heterogeneity for BDNF meta-analysis. No significant associations were found for gestational week, birth weight, and clinical comorbidity of newborns with effect sizes. Conclusions: Our findings indicated that lower BDNF and NT-3 levels may be associated with preterm birth. Future studies with larger samples sizes should investigate neurodevelopmental manifestations resulting from neurotrophic factor dysregulation among preterm infants.
RESUMO
Identificar alterações clínicas respiratórias em recém-nascidos pré-termo internados em Unidade de Terapia Intensiva Neonatal. Métodos: pesquisa documental, com145 prontuários, por meio de instrumento com variáveis sociodemográficas de recém-nascidos pré-termo e respectivas mães. Resultados: a maioria dos nascidos era do sexo masculino, 66,9% nascidos por via cirúrgica, 64,8% com prematuridade moderada e peso de nascimento entre 1.500 e 2.500 gramas. Dentre as alterações respiratórias, destacaram-se disfunção respiratória precoce, membrana hialina e apneia. Em relação aos fatores obstétricos relacionados à prematuridade, constatou-se prevalência de mulheres em trabalho de parto prematuro (42,8%), bolsa rota (32,4%) e pré-eclâmpsia (20,7%), além de outros. Conclusão: constatou-se incidência elevada de nascidos prematuros, com alterações respiratórias importantes.
Objective: to identify respiratory clinical changes in preterm newborns hospitalized in the Neonatal Intensive Care Unit. Methods: this is a documentary research with 145 medical records by an instrument with sociodemographic variables of preterm newborns and their mothers. Results: most of the newborn were male, 66.9% were born surgically, 64.8% were moderately premature, and the birth weights were between 1,500 and 2,500 grams. Among the respiratory changes, there were early respiratory dysfunction, hyaline membrane, and apnea. There was the prevalence of women in preterm labor (42.8%), water breaking (32.4%) and pre-eclampsia (20.7%) among others were found to be related to obstetric factors related to prematurity. Conclusion: a high incidence of preterm births was observed, with significant respiratory changes.
