Disparities in Trial of Labor among Women with Twin Gestations in the United States.

OBJECTIVE: The aim of the study is to examine clinical and demographic factors associated with trial of labor (TOL) among women with twin gestations eligible for a vaginal delivery. STUDY DESIGN: This was a population-based cohort study of women giving birth to twin gestations in the United States (2012-2014). Inclusion criteria for the analysis included live births greater than 23 weeks' gestation and a cephalic presenting twin. Women with prior cesarean delivery were excluded. Women were categorized by whether they underwent a TOL. Clinical and demographic characteristics associated with TOL status were evaluated using multivariable logistic regression analyses. Secondary analyses with stratification by parity and by second twin presentation were performed. RESULTS: Of 90,000 women eligible for inclusion, a minority (39.3%) underwent TOL. Women who had a greater gestational age at delivery were more likely to have a TOL. In contrast, several demographic factors were associated with decreased likelihood of TOL, including maternal age >35 years and identifying as Hispanic or Asian compared with non-Hispanic White. No differences in odds of TOL were observed for women who were identified as non-Hispanic Black versus non-Hispanic White, nor were other demographic factors such as marital status, insurance status, or educational attainment associated with undergoing TOL. Clinical factors associated with decreased odds of TOL included nulliparity, obesity, and hypertensive disorders of pregnancy. Results did not substantively change when stratified by parity or second twin presentation, nor did findings differ in the subgroup who delivered at 32 weeks of gestation or greater. CONCLUSION: In this large population of women with twins who were eligible for a TOL, a minority of individuals attempted a vaginal delivery. Demographic and clinical factors such as older maternal age, Asian or Hispanic racial or ethnic identification, nulliparity, and obesity are associated with decreased odds of undergoing TOL. KEY POINTS: · Understanding disparities in trial of labor among patients with twins is key to promoting equity.. · Older maternal age and identifying as Hispanic or Asian were associated with lower odds of TOL.. · Nulliparity, obesity, and hypertension were associated with decreased odds of TOL..

Exhaled Methane Is Associated with a Lower Heart Rate.

BACKGROUND: In humans, methane (CH4) is exclusively produced by the intestinal microbiota and has been implicated in several conditions including cardiovascular disease. After microbial production of CH4 in the gut, it steadily crosses into the systemic circulation and reaches the lungs where it can be detected in the exhaled breath, as a surrogate measure for intestinal CH4 production. Recent reports have shown an association between CH4 and vagal dysfunction as well as the inhibition of CH4 activity on ileal contractions with atropine, suggesting its action on the parasympathetic nervous system. Given these findings, we hypothesized that CH4 may be affecting resting heart rate (HR) based on the potential effect of CH4 on the vagus nerve. OBJECTIVES: Given its possible role in the parasympathetic nervous system, we aimed to study the relationship between breath CH4 and resting HR in humans. Additionally, we performed a longitudinal study analyzing the change in HR and its association with breath CH4 over time. METHODS: First, we reviewed 1,126 subjects and compared HR in subjects with detectable and undetectable breath CH4. Second, we performed a post hoc analysis of a randomized control trial to compare the change in HR for those who had an increase in breath CH4 versus those that had a decrease in breath CH4 over 14 weeks. Last, we assessed whether a larger decrease in CH4 is associated with a larger increase in HR over time. RESULTS: In the retrospective cohort, subjects with detectable CH4 had a lower HR compared to those with undetectable CH4 (73.0 ± 0.83 vs. 76.0 ± 0.44 beats/min, p = 0.01). In the post hoc analysis, a decrease in CH4 over time was associated with an increase in HR (median ∆ = 6.5 ± 8.32 beats/min, p = 0.0006). Last, we demonstrated a biological gradient whereby a larger drop in CH4 was associated with a greater increase in HR (R = -0.31, p = 0.03). CONCLUSION: Our findings suggest a potential role for the microbiome (and specifically CH4 from methanogens) to regulate HR. Considering these findings, mechanistic studies are warranted to further investigate this potential novel microbiome-neurocardiac axis.

NMR Structure of Francisella tularensis Virulence Determinant Reveals Structural Homology to Bet v1 Allergen Proteins.

Tularemia is a potentially fatal bacterial infection caused by Francisella tularensis, and is endemic to North America and many parts of northern Europe and Asia. The outer membrane lipoprotein, Flpp3, has been identified as a virulence determinant as well as a potential subunit template for vaccine development. Here we present the first structure for the soluble domain of Flpp3 from the highly infectious Type A SCHU S4 strain, derived through high-resolution solution nuclear magnetic resonance (NMR) spectroscopy; the first structure of a lipoprotein from the genus Francisella. The Flpp3 structure demonstrates a globular protein with an electrostatically polarized surface containing an internal cavity-a putative binding site based on the structurally homologous Bet v1 protein family of allergens. NMR-based relaxation studies suggest loop regions that potentially modulate access to the internal cavity. The Flpp3 structure may add to the understanding of F. tularensis virulence and contribute to the development of effective vaccines.