Probing Tissue Viscoelasticity With STL Ultrasound Shearwave Spectroscopy Using Cole-Cole Diagrams.

OBJECTIVE: Viscoelasticity is mapped by dispersion in shearwave elastography. Incomplete spectral information of shearwaves is therefore used to estimate mechanical stiffness. We propose capturing the "full-waveform-information" of the shear wave spectra to better resolve complex shear modulus µ* (ω). Approach is validated on phantom models, animal tissues, and feasibility demonstrated on human post-delivery placenta. METHODS: We captured robust estimates of µ* in ex-vivo livers subjected to water bath ablation, glutaraldehyde exposure and in the placenta. RESULTS: Complex modulus at 200 Hz is more reflective of tissue stiffness than cross-correlation estimate. Bias increased in phantoms with higher gelatin (G) (0.65: 6% G) and oil (O) (0.58: 6% G and 40% O) concentration, compared to elastic phantoms with low stiffness (0.33: 3% G). Actual tissues also reported higher bias in cross-correlation estimate (rabbit liver: 0.61, porcine liver: 2.20, and human placenta: 0.63). Stiffness is sensitive to ablation temperature, where the overall modulus changed from 3.02 KPa at 16 °C to 2.75 KPa at 56 °C in water bath. With exposure to Glutaraldehyde, the overall modulus increased from 2.37 to 9.03 KPa. Reconstruction errors in the loss modulus decreased by 68% with the power law compared to a Maxwell model in porcine livers with Cole-Cole inverse fitting. CONCLUSION: Omitting Shear wave attenuation leads to bias. Reconstruction of rheological response with a model is sensitive to its architecture and also the framework. SIGNIFICANCE: We use "full spectral information" in ultrasound shear wave elastography to better map µ*(ω) changes in viscoelastic tissues.

The Geographical Correlation Between Historical Preterm Birth Disparities and COVID-19 Burden.

Similar to obstetric outcomes, rates of SARS-CoV-2 (COVID-19) infection are not homogeneously distributed among populations; risk factors accumulate in discrete locations. This study aimed to investigate the geographical correlation between pre-COVID-19 regional preterm birth (PTB) disparities and subsequent COVID-19 disease burden. We performed a retrospective, ecological cohort study of an upstate New York birth certificate database from 2004 to 2018, merged with publicly available community resource data. COVID-19 rates from 2020 were used to allocate ZIP codes to "low-," "moderate-," and "high-prevalence" groups, defined by median COVID-19 diagnosis rates. COVID-19 cohorts were associated with poverty and educational attainment data from the US Census Bureau. The dataset was analyzed for the primary outcome of PTB using ANOVA. GIS mapping visualized PTB rates and COVID-19 disease rates by ZIP code. Within 38 ZIP codes, 123,909 births were included. The median COVID-19 infection rate was 616.5 (per 100 K). PTB (all) and COVID-19 were positively correlated, with high- prevalence COVID-19 ZIP codes also being the areas with the highest prevalence of PTB (F = 11.06, P = .0002); significance was also reached for PTB < 28 weeks (F = 15.87, P < .0001) and periviable birth (F = 16.28, P < .0001). Odds of PTB < 28 weeks were significantly higher in the "high-prevalence" COVID-19 cohort compared to the "low-prevalence" COVID 19 cohort (OR 3.27 (95% CI 2.42-4.42)). COVID-19 prevalence was directly associated with number of individuals below poverty level and indirectly associated with median household income and educational attainment. GIS mapping demonstrated ZIP code clustering in the urban center with the highest rates of PTB < 28 weeks overlapping with high COVID-19 disease burden. Historical disparities in social determinants of health, exemplified by PTB outcomes, map community distribution of COVID-19 disease burden. These data should inspire socioeconomic policies supporting economic vibrancy to promote optimal health outcomes across all communities.

Coronavirus Disease 2019 (COVID-19)-Related Stress and Menstrual Changes.

OBJECTIVE: To evaluate how stress related to the coronavirus disease 2019 (COVID-19) pandemic has affected women's menstrual cycles. We hypothesized that women with high levels of COVID-19-related stress would have more menstrual changes compared with those with lower levels of stress. METHODS: Using a cross-sectional study design, we recruited a representative sample of U.S. adult women of reproductive age (18-45 years) using nonhormonal birth control to participate in an online REDCap (Research Electronic Data Capture, Vanderbilt University) survey. COVID-19-related stress was assessed with the PSS-10-C (COVID-19 Pandemic-related Perceived Stress Scale) and dichotomized as low stress (scores lower than 25) and high stress (scores 25 or higher). Self-reported menstrual outcomes were identified as changes in cycle length, duration, or flow and increased frequency of spotting between cycles. We used χ 2 and Fisher exact tests to compare differences in outcome between the two stress groups and logistic regression models for effect estimates. RESULTS: A total of 354 women of reproductive age across the United States completed both the menstrual and COVID-19-related stress components of our survey. More than half of these women reported at least one change in their menstrual cycles since the start of the pandemic (n=191), and 10.5% reported high COVID-19-related stress (n=37). Compared with those with low COVID-19-related stress, a greater proportion of women with high COVID-19-related stress reported changes in cycle length (shorter or longer; P =.008), changes in period duration (shorter or longer; P <.001), heavier menstrual flow ( P =.035), and increased frequency of spotting between cycles ( P =.006) compared with prepandemic times. After adjusting for age, smoking history, obesity, education, and mental health history, high COVID-19-related stress was associated with increased odds of changes in menstrual cycle length (adjusted odds ratio [aOR] 2.32; 95% CI 1.12-4.85), duration (aOR 2.38; 95% CI 1.14-4.98), and spotting (aOR 2.32; 95% CI 1.03-5.22). Our data also demonstrated a nonsignificant trend of heavier menstrual flow among women with high COVID-19-related stress (aOR 1.61; 95% CI 0.77-3.34). CONCLUSION: High COVID-19-related stress is associated with significant changes in menstrual cycle length, alterations in period duration, and increased intermenstrual spotting as compared with before the pandemic. Given that menstrual health is frequently an indicator of women's overall well-being, clinicians, researchers, and public health officials must consider the association between COVID-19-related stress and menstrual disturbances.

Pregnant Women Following Bariatric Surgery: a Focus on Maternal Mental Health and Its Impact on Birth Outcomes.

PURPOSE: Bariatric surgery is associated with elevated risks for adverse birth outcomes, such as small-for-gestational-age infants (SGA). Maternal mental health is a critical regulator of fetal growth, but it is largely overlooked in pregnant women post-surgery. This study aimed to examine the associations between maternal mental health and birth outcomes in pregnant women post-bariatric surgery. MATERIALS AND METHODS: This was a retrospective analysis of medical records of women who had a singleton delivery following Roux-en-Y gastric bypass or sleeve gastrectomy. Mental health measures included depression/anxiety and substance use (cigarettes, alcohol, opioids, and marijuana). Birth outcomes were fetal growth restriction, SGA, low birthweight, and preterm birth. Logistic regressions were used to assess the associations between maternal mental health and each of the birth outcomes. A post hoc logistic regression was conducted to assess factors that influenced maternal marijuana use. RESULTS: Participants (N = 179) were mostly white (64.6%), non-Hispanic (84.5%), with a mean age of 32.7 ± 4.6 years, and mean body mass index of 37.2 ± 8.4 kg/m2 at conception. Maternal marijuana use significantly increased the odds for fetal growth restriction, SGA, low birthweight, and preterm birth. Cigarette use increased the risk for low birthweight. Conversely, alcohol use was protective of low birthweight and preterm birth. A post hoc analysis revealed that married women were less likely to use marijuana than those who were single, divorced, or widowed. CONCLUSION: This analysis identified marijuana and cigarette use as risk factors for adverse birth outcomes post-bariatric surgery. Future studies with larger sample sizes are needed to confirm study findings.

Associations Between Historically Redlined Districts and Racial Disparities in Current Obstetric Outcomes.

Importance: Despite much higher health care expenditure than comparable countries, striking racial and ethnic disparities exist in obstetric outcomes in the United States. A multifaceted exploration of the factors influencing these disparities, including the legacy of structural racism, is important to improve health outcomes for all. Objective: To characterize the association of the historic racially discriminatory home loan practice of redlining with disparities in modern obstetric outcomes. Design, Setting, and Participants: In this retrospective cohort study of a 9-county birth certificate database in the Finger Lakes region of New York state from 2005 to 2018, modern obstetric outcomes were matched with regions classified by the federal government for mortgage loan servicing based on racially discriminatory criteria from the 1940 Home Owners' Loan Corporation map (HOLC; also known as the redline map). Patients with a live birth recorded in the data system with a recorded home zip code within the historic HOLC categories were included. Data were analyzed from July to December 2019. Exposure: Regions previously categorized by historic, racially discriminatory criteria. Main Outcomes and Measures: Each HOLC area was analyzed for the primary outcome of preterm birth and secondary outcomes of obstetric and medical complications, with logistic regression to address regional and patient-level covariates. Results: From 2005 until 2018, there were 64 804 live births within the 15 zip codes overlaying historic HOLC regions. Prevalence of preterm birth increased with decreasing HOLC categories, from the lowest overall preterm birth rate of 217 of 2873 births (7.55%) in the zip code historically defined as "Best" or "Still Desirable" and the highest overall preterm birth rate of 427 of 3449 births (12.38%) in the zip code historically defined as "Hazardous." These associations with preterm birth remained significant in logistic regression controlling for poverty levels and educational attainment (adjusted odds ratio, 1.46; 95% CI, 1.08-1.97) and parental race (adjusted odds ratio, 1.38; 95% CI, 1.25-1.53). Conclusions and Relevance: In this cohort study, the linkage of historic and modern community data sets with an obstetric data set offered the opportunity to characterize modern obstetric disparities associated with a system of historic inequity. The persistence of these findings after correcting for contemporary community socioeconomic characteristics suggest potential influences of a system of profound structural inequity that ripple forward in time, with impacts that extend beyond measurable socioeconomic inequity.

Improved Recognition of Maternal Deaths Using Modern Data Analytics.

OBJECTIVE: To use a data-fusion approach to improve ascertainment of maternal deaths not detected with standard surveillance strategies. METHODS: We conducted a retrospective cohort study from the electronic health records of a tertiary medical center from 2011 to 2018. Cases of maternal death were identified in two ways: 1) using a standard medical informatics service query of hospital data and 2) using the TriNetX discovery tool as patients with a vital status of "deceased" and evidence of antecedent pregnancy exposure based on such factors as obstetric diagnostic codes or obstetric-related procedures. Potential cases of maternal death identified by the latter method underwent chart review to confirm timing of death compared with timing of last appreciable pregnancy, and to characterize the details of these deaths. The primary outcome was pregnancy-associated mortality during pregnancy or within the first postpartum year in the discovery cohort compared with the hospital-identified cohort. Secondary outcomes included causes of death and comorbidities. RESULTS: During the study period, the standard service query identified 23 maternal deaths. The discovery tool identified 18 additional patients confirmed on subsequent chart review to represent pregnancy-associated deaths, a 78% increase in ascertainment of which a greater proportion represented postpartum deaths. The majority (61%) of newly ascertained mortalities were related to cardiac causes or other medical comorbidities. Although many hospital-ascertained cases were associated with deaths after delivery of a living newborn, more deaths after early pregnancy loss or termination were identified through the discovery tool. CONCLUSION: Improved recognition of pregnancy-associated deaths can be achieved with modern data analytics.

Validations of the microchannel flow model for characterizing vascularized tissues.

The microchannel flow model postulates that stress-strain behavior in soft tissues is influenced by the time constants of fluid-filled vessels related to Poiseuille's law. A consequence of this framework is that changes in fluid viscosity and changes in vessel diameter (through vasoconstriction) have a measurable effect on tissue stiffness. These influences are examined through the theory of the microchannel flow model. Then, the effects of viscosity and vasoconstriction are demonstrated in gelatin phantoms and in perfused tissues, respectively. We find good agreement between theory and experiments using both a simple model made from gelatin and from living, perfused, placental tissue ex vivo.

"Provoked" feto-maternal hemorrhage may represent insensible cell exchange in pregnancies from 6 to 22 weeks gestational age.

OBJECTIVE: To quantify spontaneous and provoked fetal to maternal cell exchange in the first half of pregnancy. Transfer of fetal red blood cells (FRBCs) into the maternal circulation during the first half of pregnancy is poorly characterized but of clinical relevance for miscarriage management and invasive procedures. STUDY DESIGN: Prospective, descriptive cohort study of women presenting for surgical termination of pregnancy with sonographically confirmed gestational age (GA). Pre-procedural and post-procedural blood samples were collected to characterize both spontaneous (pre) and provoked (post) cell exchange with analysis via flow cytometry to quantify FRBC count. RESULTS: A total of 100 patients at 6-22 weeks GA contributed 200 matched pre- and post-procedural samples. FRBCs were identified in 69 patients including 4 who exhibited FRBCs pre-procedure only and 9 post-procedure only, for a total of 65 patients having post-procedural FRBCs. Of patients with FRBCs following their procedure, the majority (n=56, 86%) also exhibited evidence of cells before the procedure with just 9 patients (14%) exhibiting FRBCs only after. No dose-response relationship was appreciable between GA and FRBC count. CONCLUSION: After experiencing disruption of the placenta with instrumentation, roughly two thirds of patients had detectable FRBCs in maternal circulation following their procedure but-among those that did-the majority also exhibited cell presence prior to the procedure. This leads to further questions regarding the relationship between risk events and alloimmunization potential in previable pregnancies as the rate of spontaneous transplacental cell exchange may be underappreciated and the magnitude of provoked transfer may be overestimated. IMPLICATIONS: The relationship between feto-maternal hemorrhage risk events and alloimmunization potential in previable pregnancies has previously been poorly characterized but these data reveal spontaneous transplacental cell exchange may be underappreciated and the magnitude of provoked transfer may be overestimated.