Association between mode of delivery and maternal complications in a public hospital in Greater Metropolitan São Paulo, Brazil

O estudo objetivou avaliar associação entre via de parto e complicações maternas. Realizou-se coorte retrospectiva com partos ocorridos durante o ano de 2003, em um hospital público. As complicações avaliadas foram: infecção, hemorragia, histerectomia, rotura uterina, lesão de órgão contíguo, trombose venosa profunda e embolia pulmonar. Utilizou-se a odds ratio (OR) e os testes de qui-quadrado de Pearson e de Fisher, além da regressão logística. Estabeleceu-se o nível de 0,05 como significante. Foram encontradas 15 complicações. Tomando-se o parto vaginal como referência, encontrou-se associação entre cesárea e as complicações tomadas em conjunto. Analisando-se variáveis confundidoras, encontrou-se associação das complicações com hipertensão, soropositividade para HIV, placenta prévia e descolamento prematuro de placenta. Após controle para estas quatro variáveis, manteve-se a associação entre cesárea e complicações (OR = 9,7; p = 0,04). Encontrou-se também associação entre complicações e cesárea eletiva comparada ao parto vaginal (OR = 4,7; p = 0,02), e maior proporção de complicações, no limite da significância estatística, nas cesáreas eletivas comparadas à "tentativa de parto vaginal" (OR = 3; p = 0,058). Conclui-se que a cesárea associa-se a complicações maternas, mesmo após a realização de vários ajustes.The purpose of this study was to assess the relationship between mode of delivery and maternal complications, based on a retrospective cohort of all births at a public hospital in 2003. Complications included: infection, hemorrhage, hysterectomy, uterine rupture, lesions in adjacent organs, deep venous thrombosis, and pulmonary embolism. The analysis used odds ratio (OR), chi-squared test, and Fisher's exact test, besides logistic regression. Fifteen complications were identified. Taking vaginal delivery as the reference, an association was found between cesarean section and overall complications. Analysis of confounding showed an association between hypertension, HIV, placenta previa, and abruptio placentae. After controlling for these variables, an association remained between overall complications and cesarean section (OR = 9.7; p = 0.04). Another analysis comparing elective cesareans and vaginal deliveries also showed an increased risk for cesarean (OR = 4.7; p = 0.02). Finally, comparing elective cesareans with trial of labor, we found an increased proportion of complications in elective cesareans, with borderline significance (OR = 3; p = 0.058). We concluded that cesarean section is associated with maternal morbidity, even after controlling for confounders

Geography and ecology shape the phylogenetic composition of Amazonian tree communities

Aim: Amazonia hosts more tree species from numerous evolutionary lineages, both young and ancient, than any other biogeographic region. Previous studies have shown that tree lineages colonized multiple edaphic environments and dispersed widely across Amazonia, leading to a hypothesis, which we test, that lineages should not be strongly associated with either geographic regions or edaphic forest types. Location: Amazonia. Taxon: Angiosperms (Magnoliids; Monocots; Eudicots). Methods: Data for the abundance of 5082 tree species in 1989 plots were combined with a mega-phylogeny. We applied evolutionary ordination to assess how phylogenetic composition varies across Amazonia. We used variation partitioning and Moran\u27s eigenvector maps (MEM) to test and quantify the separate and joint contributions of spatial and environmental variables to explain the phylogenetic composition of plots. We tested the indicator value of lineages for geographic regions and edaphic forest types and mapped associations onto the phylogeny. Results: In the terra firme and várzea forest types, the phylogenetic composition varies by geographic region, but the igapó and white-sand forest types retain a unique evolutionary signature regardless of region. Overall, we find that soil chemistry, climate and topography explain 24% of the variation in phylogenetic composition, with 79% of that variation being spatially structured (R$^{2}$ = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R$^{2}$ = 28%). A greater number of lineages were significant indicators of geographic regions than forest types. Main Conclusion: Numerous tree lineages, including some ancient ones (>66 Ma), show strong associations with geographic regions and edaphic forest types of Amazonia. This shows that specialization in specific edaphic environments has played a long-standing role in the evolutionary assembly of Amazonian forests. Furthermore, many lineages, even those that have dispersed across Amazonia, dominate within a specific region, likely because of phylogenetically conserved niches for environmental conditions that are prevalent within regions

Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates

Aim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis). Time period: Tree-inventory plots established between 1934 and 2019. Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm. Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests. Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types

Mapping density, diversity and species-richness of the Amazon tree flora

Using 2.046 botanically-inventoried tree plots across the largest tropical forest on Earth, we mapped tree species-diversity and tree species-richness at 0.1-degree resolution, and investigated drivers for diversity and richness. Using only location, stratified by forest type, as predictor, our spatial model, to the best of our knowledge, provides the most accurate map of tree diversity in Amazonia to date, explaining approximately 70% of the tree diversity and species-richness. Large soil-forest combinations determine a significant percentage of the variation in tree species-richness and tree alpha-diversity in Amazonian forest-plots. We suggest that the size and fragmentation of these systems drive their large-scale diversity patterns and hence local diversity. A model not using location but cumulative water deficit, tree density, and temperature seasonality explains 47% of the tree species-richness in the terra-firme forest in Amazonia. Over large areas across Amazonia, residuals of this relationship are small and poorly spatially structured, suggesting that much of the residual variation may be local. The Guyana Shield area has consistently negative residuals, showing that this area has lower tree species-richness than expected by our models. We provide extensive plot meta-data, including tree density, tree alpha-diversity and tree species-richness results and gridded maps at 0.1-degree resolution