Global, regional, and national estimates of levels of preterm birth in 2014: a systematic review and modelling analysis

Mid-trimester microbial invasion of the amniotic cavity and the risk of preterm birth

OBJECTIVE

To evaluate the rate of mid-trimester microbial invasion of the amniotic cavity (MIAC) in asymptomatic women and its association with preterm birth.

STUDY DESIGN

This is a prospective cohort study of asymptomatic women undergoing mid-trimester amniocentesis for genetic testing between 14 and 24 weeks of gestation. For each participant, a sample of amniotic fluid was incubated in an aerobic and anaerobic facultative culture media and another sample was tested for the presence of specific Mycoplasma species (Ureaplasma urealyticum, Ureaplasma parvum, and Mycoplasma hominis) using quantitative-PCR. Results were not revealed to the participants or their health care providers. All participants were followed until delivery. MIAC was defined by a positive culture or a positive PCR for Mycoplasma species. The primary outcome was a spontaneous preterm birth or preterm premature rupture of membranes before 35 weeks of gestation.

RESULTS

We included 812 women at a median gestational age of 16 5/7 (interquartile: 15 6/7-17 4/7) weeks. Twenty-six (3.2%) had a spontaneous delivery before 35 weeks. We observed no case of positive PCR for Mycoplasma species and 4 (0.5%) cases of positive culture that were all considered to be skin contaminants. None of those four cases was associated with preterm birth. Nulliparity, low family income and history of preterm birth were associated with spontaneous delivery before 35 weeks.

CONCLUSION

We found no case of mid-trimester MIAC using a combination of culture and Mycoplasma-specific PCR techniques in a large cohort of low-risk asymptomatic pregnant women. We estimate that mid-trimester MIAC is rare in low-risk population but more sensitive and broad-range microbiologic techniques, such as 16S DNA detection by PCR, could be further evaluated.

RNA Sequencing Reveals Diverse Functions of Amniotic Fluid Neutrophils and Monocytes/Macrophages in Intra-Amniotic Infection

Intra-amniotic infection, the invasion of microbes into the amniotic cavity resulting in inflammation, is a clinical condition that can lead to adverse pregnancy outcomes for the mother and fetus as well as severe long-term neonatal morbidities. Despite much research focused on the consequences of intra-amniotic infection, there remains little knowledge about the innate immune cells that respond to invading microbes. We performed RNA-seq of sorted amniotic fluid neutrophils and monocytes/macrophages from women with intra-amniotic infection to determine the transcriptomic differences between these innate immune cells. Further, we sought to identify specific transcriptomic pathways that were significantly altered by the maternal or fetal origin of amniotic fluid neutrophils and monocytes/macrophages, the presence of a severe fetal inflammatory response, and pregnancy outcome (i.e., preterm or term delivery). We show that significant transcriptomic differences exist between amniotic fluid neutrophils and monocytes/macrophages from women with intra-amniotic infection, indicating the distinct roles these cells play. The transcriptome of amniotic fluid immune cells varies based on their maternal or fetal origin, and the significant transcriptomic differences between fetal and maternal monocytes/macrophages imply that those of fetal origin exhibit impaired functions. Notably, transcriptomic changes in amniotic fluid monocytes/macrophages suggest that these immune cells collaborate with neutrophils in the trafficking of fetal leukocytes throughout the umbilical cord (i.e., funisitis). Finally, amniotic fluid neutrophils and monocytes/macrophages from preterm deliveries display enhanced transcriptional activity compared to those from term deliveries, highlighting the protective role of these cells during this vulnerable period. Collectively, these findings demonstrate the underlying complexity of local innate immune responses in women with intra-amniotic infection and provide new insights into the functions of neutrophils and monocytes/macrophages in the amniotic cavity.

Associations between high temperatures in pregnancy and risk of preterm birth, low birth weight, and stillbirths: systematic review and meta-analysis

OBJECTIVE

To assess whether exposure to high temperatures in pregnancy is associated with increased risk for preterm birth, low birth weight, and stillbirth.

DESIGN

Systematic review and random effects meta-analysis.

DATA SOURCES

Medline and Web of Science searched up to September 2018, updated in August 2019.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Clinical studies on associations between high environmental temperatures, and preterm birth, birth weight, and stillbirths.

RESULTS

14 880 records and 175 full text articles were screened. 70 studies were included, set in 27 countries, seven of which were countries with low or middle income. In 40 of 47 studies, preterm births were more common at higher than lower temperatures. Exposures were classified as heatwaves, 1°C increments, and temperature threshold cutoff points. In random effects meta-analysis, odds of a preterm birth rose 1.05-fold (95% confidence interval 1.03 to 1.07) per 1°C increase in temperature and 1.16-fold (1.10 to 1.23) during heatwaves. Higher temperature was associated with reduced birth weight in 18 of 28 studies, with considerable statistical heterogeneity. Eight studies on stillbirths all showed associations between temperature and stillbirth, with stillbirths increasing 1.05-fold (1.01 to 1.08) per 1°C rise in temperature. Associations between temperature and outcomes were largest among women in lower socioeconomic groups and at age extremes. The multiple temperature metrics and lag analyses limited comparison between studies and settings.

CONCLUSIONS

Although summary effect sizes are relatively small, heat exposures are common and the outcomes are important determinants of population health. Linkages between socioeconomic status and study outcomes suggest that risks might be largest in low and middle income countries. Temperature rises with global warming could have major implications for child health.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD 42019140136 and CRD 42018118113.

Increasing trends in incidence of preterm birth among 2.5 million newborns in Guangzhou, China, 2001 to 2016: an age-period-cohort analysis

Background

The incidence of preterm birth (PTB, < 37 weeks of gestation) has been increasing in China and many other countries in recent years. However, the causes of the increase were not well understood. The current study aims to examine the contribution of maternal age, period of delivery, and maternal birth cohorts to long-term trends in preterm birth in Guangzhou, China.

Methods

In a retrospective population-based study, data were obtained from 2,535,000 singleton live births with 20–43 gestational weeks from 2001 to 2016 and recorded in the Guangzhou Perinatal Health Care and Delivery Surveillance System, in China. The age-period-cohort models were applied to investigate the temporal changes in incidences of PTB, stratified by parity.

Results

The incidence of preterm birth steadily increased from 5.1% in 2001 to 5.9% in 2016, with larger rise in primiparous mothers (from 5.0 to 5.9%) compared to multiparous mothers (from 5.6 to 5.9%). A J-shaped and a V-shaped relationship were found between maternal age and PTB among primiparous and multiparous mothers, respectively. A linear cohort effect was found among primiparous mothers with the lowest risk of PTB [risk ratio (RR) = 0.81, 95% confidence interval (CI): 0.74 to 0.89] in 1961 and the highest risk (RR = 1.06, 95% CI: 1.00 to 1.13) in 1997 compared to the mothers born in 1981. An inverse U-shaped association between maternal birth cohort and PTB was found in multiparous mothers. There were weak decreasing period effects on the trend of overall PTB among multiparous mothers and on the trend of extremely (< 27 weeks) or very (28–31 weeks) PTB among both parity groups during the period of 2001–2012.

Conclusions

Our findings showed the PTB incidences had been increasing in the past 16 years in Guangzhou, China and both maternal age and cohort effects contributed to these trends. Further studies are recommended on the impact of altered maternal age and parity on premature births and corresponding public education and public health policies.

Supplementary Information

Supplementary information accompanies this paper at 10.1186/s12889-020-09739-6.

Scaling up newborn care technologies from tertiary- to secondary-level hospitals in Malawi: an implementation case study of health professional perspectives on bubble CPAP

Background

While Malawi has achieved success in reducing overall under-five mortality, reduction of neonatal mortality remains a persistent challenge. There has, therefore, been a push to strengthen the capacity for quality newborn care at district hospitals through the implementation of innovative neonatal technologies such as bubble continuous positive airway pressure (CPAP). This study investigates tertiary- versus secondary-level hospital differences in capacities for bubble CPAP use and implications for implementation policies.

Methods

A secondary analysis of interviews was conducted with 46 health workers at one tertiary hospital and three secondary hospitals in rural Southern Malawi. Grounded theory was utilized to explore the emerging themes according to health worker cadres (nurse, clinician, district health management) and facility level (tertiary- and secondary-level facilities), which were managed using NVivo 12 (QSR International, Melbourne, Australia).

Results

We identified frequent CPAP use and the availability of neonatal nurses, physicians, and reliable electricity as facilitators for CPAP use at the tertiary hospital. Barriers at the tertiary hospital included initiation eligibility disagreements between clinicians and nurses and insufficient availability of the CPAP machines. At secondary-level hospitals, the use was supported by decision-making and initiation by nurses, involving caretakers to assist in monitoring and reliable availability of CPAP machines. Bubble CPAP was hindered by unreliable electricity, staffing shortages and rotation policies, and poor systems of accountability.

Conclusion

While this study looked at the implementation of bubble CPAP in Malawi, the findings may be applicable for scaling up other novel neonatal technologies in low-resource settings. Implementation policies must consider staffing and management structures at different health services levels for effective scale-up.

An overview of adult health outcomes after preterm birth

Preterm birth (gestational age < 37 completed weeks) has increased in prevalence in most countries in the past 20 years and now affects nearly 11% of all births worldwide. Because of treatment advances introduced in the 1970s-1980s, >95% of preterm infants who receive modern neonatal and pediatric care now survive into adulthood. The earliest birth cohorts to benefit from those advances are now in their 4th and 5th decades of life. A growing number of large cohort studies have investigated the long-term health sequelae in adulthood. Evidence has consistently shown that adult survivors of preterm birth have increased risks of chronic disorders involving various organ systems, including cardiovascular, endocrine/metabolic, respiratory, renal, neurodevelopmental, and psychiatric disorders, which either persist from childhood into adulthood or sometimes first manifest in adulthood. These disorders also lead to moderately (30% to 50%) increased mortality risks during early to mid-adulthood among persons born preterm compared with full-term, and even higher risks among those born at the earliest gestational ages. However, the majority of persons born preterm have low absolute risks of these outcomes and good self-reported quality of life in adulthood. Priorities for future research include the assessment of long-term health sequelae of preterm birth in racially and economically diverse populations, additional follow-up of existing cohorts into older adulthood, elucidation of outcomes by preterm birth subtype (e.g., different underlying causes) to improve risk stratification, and identification of protective factors that will support the long-term health trajectory and well-being of preterm-born adults.

Interleukin-8 dysregulation is implicated in brain dysmaturation following preterm birth

BACKGROUND

Preterm birth is associated with dysconnectivity of structural brain networks, impaired cognition and psychiatric disease. Systemic inflammation contributes to cerebral dysconnectivity, but the immune mediators driving this association are poorly understood. We analysed information from placenta, umbilical cord and neonatal blood, and brain MRI to determine which immune mediators link perinatal systemic inflammation with dysconnectivity of structural brain networks.

METHODS

Participants were 102 preterm infants (mean gestational age 29⁺¹ weeks, range 23⁺³-32⁺⁰). Placental histopathology identified reaction patterns indicative of histologic chorioamnionitis (HCA), and a customized immunoassay of 24 inflammation-associated proteins selected to reflect the neonatal innate and adaptive immune response was performed from umbilical cord (n = 55) and postnatal day 5 blood samples (n = 71). Brain MRI scans were acquired at term-equivalent age (41⁺⁰ weeks [range 38⁺⁰-44⁺⁴ weeks]) and alterations in white matter connectivity were inferred from mean diffusivity and neurite density index across the white matter skeleton.

RESULTS

HCA was associated with elevated concentrations of C5a, C9, CRP, IL-1β, IL-6, IL-8 and MCP-1 in cord blood, and IL-8 concentration predicted HCA with an area under the receiver operator curve of 0.917 (95% CI 0.841 - 0.993, p < 0.001). Fourteen analytes explained 66% of the variance in the postnatal profile (BDNF, C3, C5a, C9, CRP, IL-1β, IL-6, IL-8, IL-18, MCP-1, MIP-1β, MMP-9, RANTES and TNF-α). Of these, IL-8 was associated with altered neurite density index across the white matter skeleton after adjustment for gestational age at birth and at scan (β = 0.221, p = 0.037).

CONCLUSIONS

These findings suggest that IL-8 dysregulation has a role in linking perinatal systemic inflammation and atypical white matter development in preterm infants.

Temporal trends of care practices, morbidity, and mortality of extremely preterm infants over 10-years in South Wales, UK

Contemporary outcome data of preterm infants are essential to commission, evaluate and improve healthcare resources and outcomes while also assisting professionals and families in counselling and decision making. We analysed trends in clinical practice, morbidity, and mortality of extremely preterm infants over 10 years in South Wales, UK. This population-based study included live born infants < 28 weeks of gestation in tertiary neonatal units between 01/01/2007 and 31/12/2016. Patient characteristics, clinical practices, mortality, and morbidity were studied until death or discharge home. Temporal trends were examined by adjusted multivariable logistic regression models and expressed as adjusted odds ratios (aOR) with 95% confidence intervals (95% CI). A sensitivity analysis was conducted after excluding infants born at < 24 weeks of gestation. In this population, overall mortality for infants after live birth was 28.2% (267/948). The odds of mortality (aOR 0.93, 95% CI [0.88, 0.99]) and admission to the neonatal unit (0.93 [0.87, 0.98]) significantly decreased over time. Non-invasive ventilation support during stabilisation at birth increased significantly (1.26 [1.15, 1.38]) with corresponding decrease in mechanical ventilation at birth (0.89 [0.81, 0.97]) and following admission (0.80 [0.68–0.96]). Medical treatment for patent ductus arteriosus significantly decreased over the study period (0.90 [0.85, 0.96]). The incidence of major neonatal morbidities remained stable, except for a reduction in late-onset sepsis (0.94 [0.89, 0.99]). Gestation and centre of birth were significant independent factors for several outcomes. The results from our sensitivity analysis were compatible with our main results with the notable exception of death after admission to NICU (0.95 [0.89, 1.01]). There were significant improvements in survival and reduction of late-onset sepsis of extreme preterm infants in South Wales between 2007 and 2016. The sensitivity analysis suggests that some of the temporal changes observed were driven by improved outcomes in the most preterm of infants. Clinical practices related to respiratory support have changed but significant variations in clinical practices and outcomes between centres remain unexplained. The adoption of regional evidence-based clinical guidelines is likely to improve outcomes and reduce variation.

Toddlers' Language Development: The Gradual Effect of Gestational Age, Attention Capacities, and Maternal Sensitivity

Language development in toddlerhood forms the foundation for speech and language comprehension throughout childhood. Children born moderately preterm are at increased risk for problems in receptive and expressive language functioning, and they may need specific support or interventions. To understand the underlying mechanisms of language development, an integrated model of gestational age, attention capacities, and maternal sensitivity was examined in relation to receptive and expressive language functioning in toddlerhood. Our sample included 221 children (gestational age between 32–41 + 6 weeks; 54.7% born moderately preterm; 51.6% boys; 69.1% highly educated mothers). At 18 months (corrected age), attention capacities were measured using an eye-tracking procedure and maternal sensitivity was observed during mother-child interaction. Language was assessed at 24 months (corrected age). Results showed children with a higher gestational age scored higher on receptive language. This association was direct, as well as indirect through the child’s alerting attention. Expressive language was related to maternal sensitivity. Gestational age and alerting attention capacities specifically were related to language comprehension, whereas maternal sensitivity was related to speech. As language comprehension and speech in toddlerhood show different associations with biological, child, contextual, and regulation factors, they should be viewed as separate constructs in research and practice.

Automated brain morphometric biomarkers from MRI at term predict motor development in very preterm infants

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Nearly 1/3 of very preterm (VPT) infants develop motor impairments later in life.

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Better early biomarkers are needed for risk-stratification and early intervention.

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We used MRI morphometrics at term to predict 2-year motor ability in VPT infants.

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Inner cortical curvature at term is a novel biomarker of early motor aptitude.

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In regression models, morphometrics explained nearly 50% of motor score variance.

Very preterm infants are at high risk for motor impairments. Early interventions can improve outcomes in this cohort, but they would be most effective if clinicians could accurately identify the highest-risk infants early. A number of biomarkers for motor development exist, but currently none are sufficiently accurate for early risk-stratification. We prospectively enrolled very preterm (gestational age ≤31 weeks) infants from four level-III NICUs. Structural brain MRI was performed at term-equivalent age. We used a established pipeline to automatically derive brain volumetrics and cortical morphometrics – cortical surface area, sulcal depth, gyrification index, and inner cortical curvature – from structural MRI. We related these objective measures to Bayley-III motor scores (overall, gross, and fine) at two-years corrected age. Lasso regression identified the three best predictive biomarkers for each motor scale from our initial feature set. In multivariable regression, we assessed the independent value of these brain biomarkers, over-and-above known predictors of motor development, to predict motor scores. 75 very preterm infants had high-quality T2-weighted MRI and completed Bayley-III motor testing. All three motor scores were positively associated with regional cortical surface area and subcortical volumes and negatively associated with cortical curvature throughout the majority of brain regions. In multivariable regression modeling, thalamic volume, curvature of the temporal lobe, and curvature of the insula were significant predictors of overall motor development on the Bayley-III, independent of known predictors. Objective brain morphometric biomarkers at term show promise in predicting motor development in very preterm infants.

Feasibility of using an Early Warning Score for preterm or low birthweight infants in a low-resource setting: results of a mixed-methods study at a national referral hospital in Kenya

INTRODUCTION

Fifteen million babies are born prematurely, before 37 weeks gestational age, globally. More than 80% of these are in sub-Saharan Africa and Asia. 35% of all deaths in the first month of life are due to prematurity and the neonatal mortality rate is eight times higher in low-income and middle-income countries (LMICs) than in Europe. Early Warning Scores (EWS) are a way of recording vital signs using standardised charts to easily identify adverse clinical signs and escalate care appropriately. A range of EWS have been developed for neonates, though none in LMICs. This paper reports the findings of early work to examine if the use of EWS is feasible in LMICs.

METHODS

We conducted an observational study to understand current practices for monitoring of preterm infants at a large national referral hospital in Nairobi, Kenya. Using hospital records, data were collected over an 8-week period in 2019 on all live born infants born at <37 weeks and/or <2500 g (n=294, 255 mothers) in the first week of life. Using a chart adopted from the EWS developed by the British Association of Perinatal Medicine, we plotted infants' vital signs. In addition, we held group discussions with stakeholders in Kenya to examine opinions on use of EWS.

RESULTS

Recording of vital signs was variable; only 63% of infants had at least one temperature recorded and 53% had at least one heart rate and respiratory rate recorded. Stakeholders liked the traffic-light system and simplicity of the chart, though recognised challenges, such as staffing levels and ability to print in colour, to its adoption.

CONCLUSION

EWS may standardise documentation and identify infants who are at higher risk of an adverse outcome. However, human and non-human resource issues would need to be explored further before development of an EWS for LMICs.

The association between intimate partner violence and low birth weight and preterm delivery in eastern Ethiopia: Findings from a facility-based study

OBJECTIVE

To determine the associations between intimate partner violence during pregnancy and low birth weight and preterm birth among women who gave birth in public hospitals in Harari region, eastern Ethiopia.

DESIGN

A cross-sectional study was conducted among women who gave birth in public hospitals in Harari region.

PARTICIPANTS

Women aged 16-45 years who gave birth in hospitals from November 2018 to April 2019.

SETTING

Two public hospitals in Harari regional state, eastern Ethiopia MEASUREMENT: Intimate partner violence was measured using a questionnaire adapted from the World Health Organization Multi-Country Study on Women's Health and Domestic Violence against Women. Binary and multiple logistic regression was performed to establish the association between intimate partner violence and low birth weight and preterm birth. Both crude and adjusted odds ratios with 95% confidence intervals were calculated. The level of significance was set at a p-value of <0.05.

RESULTS

In this study, 39% of women reported experiencing partner violence during their most recent pregnancy. The prevalence of preterm birth and low birth weight were found to be 18.9% and 12.01%, respectively. After adjusting for potential confounders, women who experienced any intimate partner violence during pregnancy were 1.62 times (AOR = 1.62, 95%CI= 1.22, 2.78) more likely to give birth prematurely and 1.37 times (AOR= 1.37, 95%CI=1.73, 2.57) more likely to have a low birth weight infant relative to women who did not experience intimate partner violence during pregnancy.

CONCLUSION AND IMPLICATIONS FOR PRACTICE

The results underscore the need for including intimate partner violence prevention as an important strategy to reduce child mortality and morbidity. Screening pregnant women for intimate partner violence and providing support for women who have experienced violence might be helpful in tackling prematurity and low birth weight.

Associations of Vitamin D Deficiency, Parathyroid hormone, Calcium, and Phosphorus with Perinatal Adverse Outcomes. A Prospective Cohort Study

Vitamin D deficiency during pregnancy has been linked to perinatal adverse outcomes. Studies conducted to date have recommended assessing interactions with other vitamin D-related metabolites to clarify this subject. We aimed to evaluate the association of vitamin D deficiency during early pregnancy with preterm birth. Secondary outcomes included low birth weight and small for gestational age. Additionally, we explored the role that parathyroid hormone, calcium and phosphorus could play in the associations. We conducted a prospective cohort study comprising 289 pregnant women in a hospital in Granada, Spain. Participants were followed-up from weeks 10-12 of gestation to postpartum. Serum 25-hydroxyvitamin D, parathyroid hormone, calcium, and phosphorus were measured within the first week after recruitment. Pearson's χ² test, Mann-Whitney U test, binary and multivariable logistic regression models were used to explore associations between variables and outcomes. 36.3% of the participants were vitamin D deficient (<20 ng/mL). 25-hydroxyvitamin D concentration was inversely correlated with parathyroid hormone (ρ = -0.146, p = 0.013). Preterm birth was associated with vitamin D deficiency in the multivariable model, being this association stronger amongst women with parathyroid hormone serum levels above the 80th percentile (adjusted odds ratio (aOR) = 6.587, 95% CI (2.049, 21.176), p = 0.002). Calcium and phosphorus were not associated with any studied outcome. Combined measurement of 25-hydroxyvitamin D and parathyroid hormone could be a better estimator of preterm birth than vitamin D in isolation.

Assessing factors associated with poor maternal mental health among mothers of children born small and sick at 24-47 months in rural Rwanda

Background

Global investments in neonatal survival have resulted in a growing number of children with morbidities surviving and requiring ongoing care. Little is known about the caregivers of these children in low- and middle-income countries, including maternal mental health which can further negatively impact child health and development outcomes. We aimed to assess the prevalence and factors associated with poor maternal mental health in mothers of children born preterm, low birthweight (LBW), and with hypoxic ischemic encephalopathy (HIE) at 24–47 months of age in rural Rwanda.

Methods

Cross-sectional study of children 24–47 months born preterm, LBW, or with HIE, and their mothers discharged from the Neonatal Care Unit (NCU) at Kirehe Hospital between May 2015–April 2016 or discharged and enrolled in a NCU follow-up program from May 2016–November 2017. Households were interviewed between October 2018 and June 2019. Mothers reported on their mental health and their child’s development; children’s anthropometrics were measured directly. Backwards stepwise procedures were used to assess factors associated with poor maternal mental health using logistic regression.

Results

Of 287 total children, 189 (65.9%) were born preterm/LBW and 34.1% had HIE and 213 (74.2%) screened positive for potential caregiver-reported disability. Half (n = 148, 51.6%) of mothers reported poor mental health. In the final model, poor maternal mental health was significantly associated with use of violent discipline (Odds Ratio [OR] 2.29, 95% Confidence Interval [CI] 1.17,4.45) and having a child with caregiver-reported disability (OR 2.96, 95% CI 1.55, 5.67). Greater household food security (OR 0.80, 95% CI 0.70–0.92) and being married (OR = 0.12, 95% CI 0.04–0.36) or living together as if married (OR = 0.13, 95% CI 0.05, 0.37) reduced the odds of poor mental health.

Conclusions

Half of mothers of children born preterm, LBW and with HIE had poor mental health indicating a need for interventions to identify and address maternal mental health in this population. Mother’s poor mental health was also associated with negative parenting practices. Specific interventions targeting mothers of children with disabilities, single mothers, and food insecure households could be additionally beneficial given their strong association with poor maternal mental health.

Proteomics reveals region-specific hemostatic alterations in response to mechanical ventilation in a preterm lamb model of lung injury

INTRODUCTION

Preterm infants often require assisted ventilation, however ventilation when applied to the immature lung can initiate ventilator-induced lung injury (VILI). The biotrauma which underscores VILI is largely undefined, and is likely to involve vascular injury responses, including hemostasis. We aimed to use a ventilated, preterm lamb model to: (1) characterize regional alterations in hemostatic mediators within the lung and (2) assess the functional impact of protein alterations on hemostasis by analyzing temporal thrombin generation.

MATERIALS AND METHODS

Preterm lambs delivered at 124 to 127 days gestation received 90 min of mechanical ventilation (positive end-expiratory pressure = 8 cm H₂O, V_T = 6-8 ml/kg) and were compared with unventilated control lambs. At study completion, lung tissue was taken from standardized nondependent and gravity-dependent regions, and Orbitrap-mass spectrometry and KEGG were used to identify and map regional alterations in hemostasis pathway members. Temporal alterations in plasma thrombin generation were assessed.

RESULTS

Ventilation was distributed towards the nondependent lung. Significant changes in hemostatic protein abundance, were detected at a two-fold higher rate in the nondependent lung when compared with the gravity-dependent lung. Seven proteins were uniquely altered in non-dependent lung (SERPINA1, MYL12A, RAP1B, RHOA, ITGB1, A2M, GNAI2), compared with a single proteins in gravity-dependent lung (COL1A2). Four proteins were altered in both regions (VTN, FGG, FGA, and ACTB). Tissue protein alterations were mirrored by plasma hypocoagulability at 90-minutes of ventilation.

CONCLUSIONS

We observed regionally specific, hemostatic alterations within the preterm lung together with disturbed fibrinolysis following a short period of mechanical ventilation.

Ten-year time trends in preterm birth during a sociodemographic transition period: a retrospective cohort study in Shenzhen, China

OBJECTIVES

To investigate time trends of preterm birth and estimate the contributions of risk factors to the changes in preterm birth rates over a decade (2009-2018) of transitional period in Shenzhen, China.

DESIGN

Retrospective cohort study between 2009 and 2018.

SETTING

All births in Baoan during January 2009 and December 2018 registered in the Shenzhen Birth Registry Database.

PARTICIPANTS

478 044 live births were included with sociodemographic and medical records for both women and infants.

OUTCOME MEASURES

The incidence rate of preterm birth stratified by different maternal and infant characteristics. Multiple logistic regression was used to identify significant risk factors associated with preterm birth. The population attributable risk fraction of each factor was calculated to estimate its contribution to variations of preterm birth rate over the 10 years.

RESULTS

A total of 27 829 preterm births from 478 044 (5.8%) live births were recorded and the preterm birth rate increased from 5.5% in 2009 to 6.2% in 2018. Medically induced preterm birth rate increased from 2.0% in 2009 to 3.4% in 2018 while spontaneous preterm labour rate decreased from 3.3% to 2.7% over the decade years. Risk factors including multiple pregnancy (0.28% increase) drove the rise of preterm birth rate, whereas changes in maternal educational attainment (0.22% reduction) and prenatal care utilisation (0.45% reduction) had contributed to the decline in preterm birth rate.

CONCLUSIONS

An uptrend of preterm birth rate was observed in an area under rapid sociodemographic transitions during 2009-2018 and the changes were associated with these sociodemographic transitions. Continued investments in girls' education and prenatal care have the potential of reducing preterm birth rate.

The association between periconceptional folic acid supplementation and the risk of preterm birth: a population-based retrospective cohort study of 200,000 women in China

PURPOSE

The aim of this study was to examine the association between periconceptional folic acid (FA) supplementation and risk of preterm birth.

METHODS

We conducted a retrospective cohort study in women aged 18-49 who participated in the NFPHEP from 2010 to 2018, and had a singleton livebirth in 129 counties in southwest China. Participants were divided into four groups according to the time period starting FA use: no use, after the last menstrual period, at least 1-2 months before the last menstrual period, at least 3 months before the last menstrual period. The outcomes were preterm birth (gestation < 37 weeks) and early preterm birth (gestation < 34 weeks).

RESULTS

201,477 women were included and 191,809 (95.2%) had taken FA during periconception. Compared with women who did not take FA, women who started taking FA 1-2 months before their last menstrual period had a 15% lower risk of preterm birth (aOR = 0.85, 95% CI 0.79-0.92), and women who started taking FA at least 3 months before their last menstrual period had a 20% lower risk of preterm birth (aOR = 0.80, 95% CI 0.75-0.87), but women who started taking FA after their last menstrual period did not appear to reduce the risk of preterm birth.

CONCLUSIONS

In this study of 200,000 Chinese women, periconceptional supplementation with FA was associated with a lower risk of preterm birth. Women who started taking FA at least 3 months before their last menstrual period were more likely to reduce the risk of preterm birth.

Impact of COVID-19 mitigation measures on the incidence of preterm birth: a national quasi-experimental study

Background

Preterm birth is the leading cause of child mortality globally, with many survivors experiencing long-term adverse consequences. Preliminary evidence suggests that numbers of preterm births greatly reduced following implementation of policy measures aimed at mitigating the effects of the COVID-19 pandemic. We aimed to study the impact of the COVID-19 mitigation measures implemented in the Netherlands in a stepwise fashion on March 9, March 15, and March 23, 2020, on the incidence of preterm birth.

Methods

We used a national quasi-experimental difference-in-regression-discontinuity approach. We used data from the neonatal dried blood spot screening programme (2010–20) cross-validated against national perinatal registry data. Stratified analyses were done according to gestational age subgroups, and sensitivity analyses were done to assess robustness of the findings. We explored potential effect modification by neighbourhood socioeconomic status, sex, and small-for-gestational-age status.

Findings

Data on 1 599 547 singleton neonates were available, including 56 720 births that occurred after implementation of COVID-19 mitigation measures on March 9, 2020. Consistent reductions in the incidence of preterm birth were seen across various time windows surrounding March 9 (± 2 months [n=531 823] odds ratio [OR] 0·77, 95% CI 0·66–0·91, p=0·0026; ± 3 months [n=796 531] OR 0·85, 0·73–0·98, p=0·028; ± 4 months [n=1 066 872] OR 0·84, 0·73–0·97, p=0·023). Decreases in incidence observed following the March 15 measures were of smaller magnitude, but not statistically significant. No changes were observed after March 23. Reductions in the incidence of preterm births after March 9 were consistent across gestational age strata and robust in sensitivity analyses. They appeared confined to neighbourhoods of high socioeconomic status, but effect modification was not statistically significant.

Interpretation

In this national quasi-experimental study, initial implementation of COVID-19 mitigation measures was associated with a substantial reduction in the incidence of preterm births in the following months, in agreement with preliminary observations elsewhere. Integration of comparable data from across the globe is needed to further substantiate these findings and start exploring underlying mechanisms.

Funding

None.

Multichannel Esophageal Heart Rate Monitoring of Preterm Infants

OBJECTIVE

Autonomic dysregulation in preterm infants requires continuous monitoring of vital signs such as heart rate over days to months. Unfortunately, common surface electrodes are prone to electrocardiography (ECG) signal artifacts and cause serious skin irritations during long-term use. In contrast, esophageal ECG is known to be very sensitive due to the proximity of electrodes and heart and insensitive to external influences. This study addresses if multichannel esophageal ECG qualifies for heart rate monitoring in preterm infants.

METHODS

We recorded esophageal leads with a multi-electrode gastric feeding tube in a clinical study with 13 neonates and compared the heartbeat detection performance with standard surface leads. A computationally simple and versatile ECG wave detection algorithm was used.

RESULTS

Multichannel esophageal ECG manifested heartbeat sensitivity and positive predictive value greater than 98.5% and significant less false negative (FN) ECG waves as compared to surface ECG due to site-typical electrode motion artifacts. False positive bradycardia as indicated with more than 13 consecutive FN ECG waves was equally expectable in esophageal and surface channels. No adverse events were reported for the multi-electrode gastric feeding tube.

CONCLUSION

Heart rate monitoring of preterm infants with multiple esophageal electrodes is considered as feasible and reliable. Less signal artifacts will improve the detection of bradycardia, which is crucial for immediate interventions, and reduce alarm fatigue.

SIGNIFICANCE

Due to the possibility to integrate the multichannel ECG into a gastric feeding tube and meanwhile omit harmful skin electrodes, the presented system has great potential to facilitate future intensive care of preterm infants.

Cohort profile: molecular signature in pregnancy (MSP): longitudinal high-frequency sampling to characterise cross-omic trajectories in pregnancy in a resource-constrained setting

PURPOSE

A successful pregnancy relies on the interplay of various biological systems. Deviations from the norm within a system or intersystemic interactions may result in pregnancy-associated complications and adverse pregnancy outcomes. Systems biology approaches provide an avenue of unbiased, in-depth phenotyping in health and disease. The molecular signature in pregnancy (MSP) cohort was established to characterise longitudinal, cross-omic trajectories in pregnant women from a resource constrained setting. Downstream analysis will focus on characterising physiological perturbations in uneventful pregnancies, pregnancy-associated complications and adverse outcomes.

PARTICIPANTS

First trimester pregnant women of Karen or Burman ethnicity were followed prospectively throughout pregnancy, at delivery and until 3 months post partum. Serial high-frequency sampling to assess whole blood transcriptomics and microbiome composition of the gut, vagina and oral cavity, in conjunction with assessment of gene expression and microbial colonisation of gestational tissue, was done for all cohort participants.

FINDINGS TO DATE

381 women with live born singletons averaged 16 (IQR 15-18) antenatal visits (13 094 biological samples were collected). At 5% (19/381) the preterm birth rate was low. Other adverse events such as maternal febrile illness 7.1% (27/381), gestational diabetes 13.1% (50/381), maternal anaemia 16.3% (62/381), maternal underweight 19.2% (73/381) and a neonate born small for gestational age 20.2% (77/381) were more often observed than preterm birth.

FUTURE PLANS

Results from the MSP cohort will enable in-depth characterisation of cross-omic molecular trajectories in pregnancies from a population in a resource-constrained setting. Moreover, pregnancy-associated complications and unfavourable pregnancy outcomes will be investigated at the same granular level, with a particular focus on population relevant needs such as effect of tropical infections on pregnancy. More detailed knowledge on multiomic perturbations will ideally result in the development of diagnostic tools and ultimately lead to targeted interventions that may disproportionally benefit pregnant women from this resource-limited population.

TRIAL REGISTRATION NUMBER

NCT02797327.

Effects of in-hospital breast feeding on brain function development in preterm infants in China: study protocol for a prospective longitudinal cohort study

INTRODUCTION

Due to immature brain development, preterm infants are more likely to develop neurological developmental defects compared with full-term infants. Most preterm infants without neurodevelopmental damage can eventually reach the same scholastic level as their same-age peers; however, some show persistent impairment. Breast feeding (BF), which is an important public health measure, is of great significance for preterm infants. Various active substances in breast milk promote the development of the brain and central nervous system in premature infants. We present a protocol for a prospective longitudinal cohort study to explore the effect of in-hospital BF on brain development in preterm infants and possible influencing factors.

METHODS AND ANALYSIS

This study will enrol 247 Chinese preterm infants (gestational age: 30-34 weeks) delivered in Women's Hospital School of Medicine, Zhejiang University, and transferred to the neonatal intensive care unit. Demographic, clinical and in-hospital BF data will be collected through electronic medical records. Moreover, follow-up data will be obtained by telephone, interview or online. Measurements will be obtained using the Breastfeeding Self-Efficacy Scale-Short Form, neuroimaging with functional near-infrared spectroscopy, extrauterine growth restriction and the Ages and Stages Questionnaire. Follow-up will be performed at 3, 6 and 12 months after birth.

ETHICS AND DISSEMINATION

This study has been approved by the Women's Hospital School of Medicine Zhejiang University Medical Ethics Committee (2019-058). The study results are expected to be published in peer-reviewed journals and reported at relevant national and international conferences.

TRIAL REGISTRATION NUMBER

ChiCTR1900027648; Pre-results.

Contractile function of the cervix plays a role in normal and pathological pregnancy and parturition

The cervix plays an integral part in ensuring the proper timing of pregnancy and parturition. It maintains the fetus within the uterus and protects it from pathogens present in the vaginal canal. The cervix undergoes extensive remodeling during pregnancy and parturition. This process is associated with collagen degradation, an increase in immune cell response and inflammation in the cervix. However, our understanding of the role of cervical smooth muscles and their contribution to cervical remodeling is still lacking. In this paper, we propose that the active contractile function of the cervix influences cervical remodeling during pregnancy and parturition. Contraction of the cervical smooth muscles helps the cervix to remain firm and closed during early pregnancy, while relaxation of the cervical smooth muscles help facilitate cervical dilatation during labor. This contractile function of the cervix can be influenced by endocrine signals, such as estrogen, progesterone, and oxytocin; local paracrine signals, such as inflammatory chemokines and cytokines, as well as extracellular vesicles, such as exosomes and ectosomes; and by pharmacological agents used for cervical ripening and the induction of labor. A deeper understanding of the role of smooth muscles in cervical remodeling can help us elucidate the cellular processes in the cervix during pregnancy and parturition. This can also help in finding critical signaling pathways and therapeutic targets in the cervix that may decrease the rates of premature cervical ripening and preterm birth.

Are morphokinetic parameters of embryo development associated with adverse perinatal outcomes following fresh blastocyst transfer?

RESEARCH QUESTION

Are obstetric and perinatal complications associated with morphokinetic parameters of embryo development?

DESIGN

This proof-of-concept pilot study included a retrospective analysis of embryo morphokinetic parameters of 85 live births following day 5 single blastocyst transfer. Kinetic variables included time interval (hours) from time of pronuclei fading (tPNf) to: time of 2 cells (tPNf-t2), 9 cells (tPNf-t9), morula (tPNf-tM), start of blastulation (tPNf-tSB), full blastocyst (tPNf-tB) and expanded blastocyst (tPNf-tEB). Multivariable logistic models were used to calculate the risk of perinatal complications after adjustment for confounders.

RESULTS

The mean interval of tPNf-tSB was significantly longer for newborns with congenital anomalies compared with healthy newborns (79.49 ± 5.78 versus 71.7 ± 6.3, respectively, P = 0.01) and for embryos of women who had gestational diabetes mellitus compared with normoglycemic women (76.56 ± 7.55 versus 71.5 ± 6.13, respectively, P = 0.015). The mean interval of tPNf-t9 was significantly longer for low-birthweight newborns compared with normal weight (49.25 ± 5.54 versus 45.47 ± 4.77, respectively, P = 0.01). Preterm delivery was associated with several longer intervals of cell divisions compared with delivery at term (tPNf-t5: 28.76 ± 3.13 versus 26.64 ± 2.40, respectively, P = 0.01; tPNf-t6: 30.10 ± 3.05 versus 27.68 ± 2.30, respectively, P < 0.001; tPNf-t7: 32.08 ± 4.11 versus 28.70 ± 2.67, respectively, P < 0.001; tPNf-t8: 34.75 ± 4.95 versus 30.70 ± 4.10, respectively, P < 0.001; tPNf-t9: 50.23 ± 5.87 versus 45.44 ± 4.67, respectively, P < 0.001). For each of the outcomes, the association remained significant after adjusting for confounders.

CONCLUSION

This study indicates that there may be a possible association between adverse perinatal outcomes and morphokinetic parameters. Larger studies are needed to establish this association.

The impact of funneling shape on the secondary prevention of spontaneous preterm birth in patients treated with either an Arabin pessary, McDonald cerclage or early total cervical occlusion (ETCO)

OBJECTIVE

Cervical funneling is associated with spontaneous preterm birth (sPTB). The aim of this analysis was to assess the relationship between funneling shape and the response to the McDonald cerclage, the Arabin pessary and the early total cervical occlusion (ETCO).

METHODS

We retrospectively analyzed data of 312 randomly selected singleton pregnancies with cervical shortening <25 mm or normal cervical length and evaluated them according to the progression of funneling: control group (n = 46), cervical shortening without funneling (n = 107), V-shaped funneling (n = 68), U-shaped funneling (n = 47), and prolapse of the amniotic sac (n = 44). We evaluated sPTB rates <34, <28, <32, and <37 weeks as well as prolongation of gestation and birthweight.

RESULTS

Regarding the rate of sPTB <34 weeks there was no statistical significance in either of the comparisons between control group and each of the four risk groups. Regarding prolongation of gestation we demonstrated a statistical significance for all risk groups compared to the control group (all p < .05) with the lowest prolongation rate noted in the group with amnion prolapse and the highest in the group with isolated cervical shortening without funneling. Similarly, progression of funnel shape resulted in an absolute decrease of birthweight for all risk groups compared to the control group, albeit not significant for the group with U-shaped funneling (p = .1058).

CONCLUSION

Independent of the treatment, there was a significant impact of funneling shape on pregnancy duration and birthweight.

Study Design and Baseline Profiles of Participants in the Tianjin Birth Cohort (TJBC) in China

Background

To investigate the causal link between early-life exposures and long-term health consequences, we established the Tianjin Birth Cohort (TJBC), a large-scale prospective cohort in northern China.

Methods

TJBC aims to enroll 10,000 families with follow-ups from pregnancy until children’s six year-old. Pregnant women and their spouses were recruited through a three-tier antenatal healthcare system at early pregnancy, with follow-ups at mid-pregnancy, late pregnancy, delivery, 42 days after delivery, 6 months after delivery, and each year until 6 years old. Antenatal/neonatal examination, biological samples and questionnaires were collected.

Results

From August 2017 to January 2019, a total of 3,924 pregnant women have already been enrolled, and 1,697 women have given birth. We observed the prevalence of gestational diabetes mellitus as 18.1%, anemia as 20.4%, and thyroid hypofunction as 2.0%. In singleton live births, 5.6% were preterm birth (PTB), 3.7% were low birth weight, and 7.3% were macrosomia. Based on current data, we also identified maternal/paternal factors which increased the risk of PTB, including paternal age (OR 1.07; 95% CI, 1.01–1.14 for each year increase), vaginal bleeding during pregnancy (OR 2.82; 95% CI, 1.54–5.17) and maternal early-pregnancy BMI (OR 1.08; 95% CI, 1.01–1.15 for each kg/m² increase).

Conclusion

TJBC has the strength of collecting comprehensive maternal, paternal, and childhood information. With a diverse range of biological samples, we are also engaging with emerging new technologies for multi-omics research. The study would provide new insight into the causal link between macro/micro-environmental exposures of early life and short/long-term health consequences.

High Burden of Undernutrition among At-Risk Children in Neonatal Follow-Up Clinic in Rwanda

Background

Sufficient knowledge of the disproportionate burden of undernutrition among vulnerable children is required for accelerating undernutrition reduction in low-income countries.

Objectives

We aimed to assess the prevalence of stunting, underweight and wasting and associated factors among high-risk children born preterm, with low birth weight or other birth and neurodevelopmental injuries, who received nutritional support and clinical care follow-up in a Pediatric Development Clinic (PDC) in rural Rwanda.

Methods

This cross-sectional study included all children from rural areas enrolled in PDC between April 2014-September 2017 aged 6-59 months at their last visit during this period. Anthropometric measurements, socioeconomic and clinical characteristics were extracted from an electronic medical records system. We used the World Health Organization child growth standards to classify stunting, underweight and wasting. Factors associated with undernutrition were identified using logistic regression analysis.

Results

Of 641 children, 58.8% were stunted, 47.5% were underweight and 25.8% were wasted. Small for gestational age was associated with increased odds of stunting [OR 2.63; 95% CI 1.58-4.36] and underweight (OR 2.33; 95% CI 1.46-3.71), while history of feeding difficulties was significantly associated with wasting (OR: 3.36; 95% CI: 2.20-5.13) and underweight (OR: 2.68; 95% CI: 1.78-4.04). Later age at PDC enrollment was associated with increased odds of stunting (OR: 1.06; 95% CI: 1.01-1.11), underweight (OR: 1.09; 95% CI: 1.05-1.14) and wasting (OR: 1.07; 95% CI: 1.04-1.10).

Conclusions

The prevalence of stunting, underweight and wasting are high in this at-risk population, highlighting the need for specific interventions to address undernutrition among children with similar characteristics. Early PDC enrollment of high-risk infants may reduce undernutrition risk.

Blood gene transcript signature profiling in pregnancies resulting in preterm birth: A systematic review

OBJECTIVE

To pursue a systematic review and summarise the current evidence for the potential of transcriptome molecular profiling in investigating the preterm phenotype.

STUDY DESIGN

We systematically reviewed the literature, using readily available electronic databases (i.e. PubMed/Medline, Embase, Scopus and Web of Science) from inception until March 2020 to identify investigations of maternal blood-derived RNA profiling in preterm birth (PTB). Studies were included if circulating coding or non-coding RNA was analysed in maternal blood during pregnancy and/or at delivery. Interventional trials were not included. The primary outcome was the availability of whole genome expression patterns evaluated in pregnancies resulting in preterm deliveries.

RESULTS

A total of 35 articles were included in the final analysis. Most of the studies were conducted in high-income countries and published in the last decade. Apart from spontaneous PTB, a variety of phenotypes leading to preterm delivery were reported. Differences in sampling methods, target gene selection and laboratory protocols severely limited any quantitative comparisons. Most of the studies revealed that gene expression profiling during pregnancy has high potential for identifying women at risk of spontaneous and/or non-spontaneous PTB as early as in the first trimester.

CONCLUSION

Assessing maternal blood-derived transcriptional signatures for PTB risk in pregnant women holds promise as a screening approach. However, longitudinally followed, prospective pregnancy cohorts are lacking. These are relevant for identifying causes leading to PTB and whether prediction of spontaneous PTB or co-morbidities associated with PTB is achievable. More emphasis on widely employed standardised protocols is required to ensure comparability of results.

Challenges of access to kidney care for children in low-resource settings

Kidney disease is a global public health concern across the age spectrum, including in children. However, our understanding of the true burden of kidney disease in low-resource areas is often hampered by a lack of disease awareness and access to diagnosis. Chronic kidney disease (CKD) in low-resource settings poses multiple challenges, including late diagnosis, the need for ongoing access to care and the frequent unavailability of costly therapies such as dialysis and transplantation. Moreover, children in such settings are at particular risk of acute kidney injury (AKI) owing to preventable and/or reversible causes - many children likely die from potentially reversible kidney disease because they lack access to appropriate care. Acute peritoneal dialysis (PD) is an important low-cost treatment option. Initiatives, such as the Saving Young Lives programme, to train local medical staff from low-resource areas to provide care for AKI, including acute PD, have already saved hundreds of children. Future priorities include capacity building for both educational purposes and to provide further resources for AKI management. As local knowledge and confidence increase, CKD management strategies should also develop. Increased awareness and advocacy at both the local government and international levels will be required to continue to improve the diagnosis and treatment of AKI and CKD in children worldwide.

Midwifery continuity of care versus standard maternity care for women at increased risk of preterm birth: A hybrid implementation-effectiveness, randomised controlled pilot trial in the UK

BACKGROUND

Midwifery continuity of care is the only health system intervention shown to reduce preterm birth (PTB) and improve perinatal survival, but no trial evidence exists for women with identified risk factors for PTB. We aimed to assess feasibility, fidelity, and clinical outcomes of a model of midwifery continuity of care linked with a specialist obstetric clinic for women considered at increased risk for PTB.

METHODS AND FINDINGS

We conducted a hybrid implementation-effectiveness, randomised, controlled, unblinded, parallel-group pilot trial at an inner-city maternity service in London (UK), in which pregnant women identified at increased risk of PTB were randomly assigned (1:1) to either midwifery continuity of antenatal, intrapartum, and postnatal care (Pilot study Of midwifery Practice in Preterm birth Including women's Experiences [POPPIE] group) or standard care group (maternity care by different midwives working in designated clinical areas). Pregnant women attending for antenatal care at less than 24 weeks' gestation were eligible if they fulfilled one or more of the following criteria: previous cervical surgery, cerclage, premature rupture of membranes, PTB, or late miscarriage; previous short cervix or short cervix this pregnancy; or uterine abnormality and/or current smoker of tobacco. Feasibility outcomes included eligibility, recruitment and attrition rates, and fidelity of the model. The primary outcome was a composite of appropriate and timely interventions for the prevention and/or management of preterm labour and birth. We analysed by intention to treat. Between 9 May 2017 and 30 September 2018, 334 women were recruited; 169 women were allocated to the POPPIE group and 165 to the standard group. Mean maternal age was 31 years; 32% of the women were from Black, Asian, and ethnic minority groups; 70% were in employment; and 46% had a university degree. Nearly 70% of women lived in areas of social deprivation. More than a quarter of women had at least one pre-existing medical condition and multiple risk factors for PTB. More than 75% of antenatal and postnatal visits were provided by a named/partner midwife, and a midwife from the POPPIE team was present at 80% of births. The incidence of the primary composite outcome showed no statistically significant difference between groups (POPPIE group 83.3% versus standard group 84.7%; risk ratio 0.98 [95% confidence interval (CI) 0.90 to 1.08]; p = 0.742). Infants in the POPPIE group were significantly more likely to have skin-to-skin contact after birth, to have it for a longer time, and to breastfeed immediately after birth and at hospital discharge. There were no differences in other secondary outcomes. The number of serious adverse events was similar in both groups and unrelated to the intervention (POPPIE group 6 versus standard group 5). Limitations of this study included the limited power and the nonmasking of group allocation; however, study assignment was masked to the statistician and researchers who analysed the data.

CONCLUSIONS

In this study, we found that it is feasible to set up and achieve fidelity of a model of midwifery continuity of care linked with specialist obstetric care for women at increased risk of PTB in an inner-city maternity service in London (UK), but there is no impact on most outcomes for this population group. Larger appropriately powered trials are needed, including in other settings, to evaluate the impact of relational continuity and hypothesised mechanisms of effect based on increased trust and engagement, improved care coordination, and earlier referral on disadvantaged communities, including women with complex social factors and social vulnerability.

TRIAL REGISTRATION

We prospectively registered the pilot trial on the UK Clinical Research Network Portfolio Database (ID number: 31951, 24 April 2017). We registered the trial on the International Standard Randomised Controlled Trial Number (ISRCTN) (Number: 37733900, 21 August 2017) and before trial recruitment was completed (30 September 2018) when informed that prospective registration for a pilot trial was also required in a primary clinical trial registry recognised by WHO and the International Committee of Medical Journal Editors (ICMJE). The protocol as registered and published has remained unchanged, and the analysis conforms to the original plan.

Epidemiology of preterm birth in Ethiopia: systematic review and meta-analysis

Background

Globally, complications of preterm birth are among the most common cause of neonatal mortality. In Ethiopia, the neonatal mortality reduction is not worthy of attention. Hence, this study reviewed the prevalence of preterm birth and factors associated with preterm birth in Ethiopia.

Methods

The review protocol of this study has been registered in PROSPERO (CRD42017077356). The PRISMA guideline was followed for this review. Studies that assessed the prevalence and/or associated factors of preterm birth in Ethiopia and published from Jan 01, 2009 to Dec 31, 2019 were considered. Studies were searched from the PubMed and Science Direct among medical electronic databases and Google Scholar. Random-effects model was used for detected heterogeneity among studies. Publication bias and sensitivity analysis were assessed. Pooled estimates with its 95% confidence interval were reported using forest plots. The quality of evidence from the review was assessed using GRADE approach.

Results

Twenty-two studies involving a total of 12,279 participants were included. The overall pooled prevalence of preterm birth in Ethiopia was 10.48% (95% CI: 7.98–12.99). Pooled odds ratio showed rural residence (AOR = 2.34, 95% CI: 1.35–4.05), being anemic (AOR = 2.59, 95% CI: 1.85–3.64), < 4 antenatal care visits (AOR = 2.34, 95%CI: 1.73–3.33), pregnancy induced hypertension (AOR = 3.49, 95% CI: 2.45–4.97), prelabor rapture of membrane (AOR = 4.42, 95% CI: 2.28–8.57), antepartum hemorrhage (AOR = 5.02, 95% CI: 2.90–8.68), multiple pregnancies (AOR = 3.89, 95% CI: 2.52–5.99), past adverse birth outcomes (AOR = 3.24, 95% CI: 2.53–4.15) and chronic illness (AOR = 4.89, 95%CI: 3.12–7.66) were associated with increased likelihood of preterm birth. Further, support during pregnancy was associated with reduced occurrence of preterm birth.

Conclusion

The pooled national level prevalence of preterm birth in Ethiopia is high. Socio demographic, nutritional, health care, obstetric and gynecologic, chronic illness and medical conditions, behavioral and lifestyle factors are the major associated factors of preterm birth in Ethiopia. This evidence is graded as low grade. Thus, efforts should be intensified to address reported risk factors to relieve the burden of preterm birth in the study setting, Ethiopia.

Global burden of preterm birth

Preterm birth is a live birth that occurs before 37 completed weeks of pregnancy. Approximately 15 million babies are born preterm annually worldwide, indicating a global preterm birth rate of about 11%. With 1 million children dying due to preterm birth before the age of 5 years, preterm birth is the leading cause of death among children, accounting for 18% of all deaths among children aged under 5 years and as much as 35% of all deaths among newborns (aged <28 days). There are significant variations in preterm birth rates and mortality between countries and within countries. However, the burden of preterm birth is particularly high in low- and middle-income countries, especially those in Southeast Asia and sub-Saharan Africa. Preterm birth rates are rising in many countries. The issue of preterm birth is of paramount significance for achieving United Nations Sustainable Development Goal 3 target #3.2, which aims to end all preventable deaths of newborns and children aged under 5 years by 2030.

Pregnancy-specific transcriptional changes upon endotoxin exposure in mice

Objectives Pregnant women are more susceptible to certain infections; however, this increased susceptibility is not fully understood. Herein, systems biology approaches were utilized to elucidate how pregnancy modulates tissue-specific host responses to a bacterial product, endotoxin. Methods Pregnant and non-pregnant mice were injected with endotoxin or saline on 16.5 days post coitum (n=8-11 per group). The uterus, cervix, liver, adrenal gland, kidney, lung, and brain were collected 12 h after injection and transcriptomes were measured using microarrays. Heatmaps and principal component analysis were used for visualization. Differentially expressed genes between groups were assessed using linear models that included interaction terms to determine whether the effect of infection differed with pregnancy status. Pathway analysis was conducted to interpret gene expression changes. Results We report herein a multi-organ atlas of the transcript perturbations in pregnant and non-pregnant mice in response to endotoxin. Pregnancy strongly modified the host responses to endotoxin in the uterus, cervix, and liver. In contrast, pregnancy had a milder effect on the host response to endotoxin in the adrenal gland, lung, and kidney. However, pregnancy did not drastically affect the host response to endotoxin in the brain. Conclusions Pregnancy imprints organ-specific host immune responses upon endotoxin exposure. These findings provide insight into the host-response against microbes during pregnancy.

Impact of regionalisation and case-volume on neonatal and perinatal mortality: an umbrella review

OBJECTIVE

This umbrella review summarises and critically appraises the evidence on the effects of regulated or high-volume perinatal care on outcome among very low birth weight/very preterm infants born in countries with neonatal mortality <5/1000 births.

INTERVENTION/EXPOSITION

Perinatal regionalisation, centralisation, case-volume.

PRIMARY OUTCOMES

Death.

SECONDARY OUTCOMES

Disability, discomfort, disease, dissatisfaction.

METHODS

On 29 November 2019 a systematic search in MEDLINE and Embase was performed and supplemented by hand search. Relevant systematic reviews (SRs) were critically appraised with A MeaSurement Tool to Assess systematic Reviews 2.

RESULTS

The literature search revealed 508 hits and three SRs were included. Effects of perinatal regionalisation were assessed in three (34 studies) and case-volume in one SR (6 studies). Centralisation has not been evaluated. The included SRs reported effects on 'death' (eg, neonatal), 'disability' (eg, mental status), 'discomfort' (eg, maternal sensitivity) and 'disease' (eg, intraventricular haemorrhages). 'Dissatisfactions' were not reported. The critical appraisal showed a heterogeneous quality ranging from moderate to critically low. A pooled effect estimate was reported once and showed a significant favour of perinatal regionalisation in terms of neonatal mortality (OR 1.60, 95% CI 1.33-1.92). The qualitative evidence synthesis of the two SRs without pooled estimate suggests superiority of perinatal regionalisation in terms of different mortality and non-mortality outcomes. In one SR, contradictory results of lower neonatal mortality rates were reported in hospitals with higher birth volumes.

CONCLUSIONS

Regionalised perinatal care seems to be a crucial care strategy to improve the survival of very low birth weight and preterm births. To overcome the low and critically low methodological quality and to consider additional clinical and patient-reported results that were not addressed by the SRs included, we recommend an updated SR. In the long term, an international, uniformly conceived and defined perinatal database could help to provide evidence-based recommendations on optimal strategies to regionalise perinatal care.

PROSPERO REGISTRATION NUMBER

CRD42018094835.

Cellular immune responses in amniotic fluid of women with a sonographic short cervix

Objectives A sonographic short cervix is one of the strongest predictors of preterm delivery. However, the cellular immune composition of amniotic fluid in women with a short cervix has not yet been described. Herein, we determined cellular and soluble immune responses in amniotic fluid from pregnant women with a mid-trimester asymptomatic short cervix. Methods Amniotic fluid samples (n=77) were collected from asymptomatic women with a cervical length between 15 and 25 mm (n=36, short cervix) or ≤15 mm (n=41, severely short cervix) diagnosed by ultrasound. Flow cytometry and multiplex measurement of cytokines/chemokines were performed. Results (1) The cellular immune composition of amniotic fluid did not differ between women with a severely short cervix (≤15 mm) and those with a short cervix 15-25 mm; (2) amniotic fluid concentrations of multiple cytokines/chemokines were higher in women with a severely short cervix (≤15 mm) than in those with a short cervix 15-25 mm; (3) the cellular immune composition of amniotic fluid did not differ between women with a severely short cervix (≤15 mm) who ultimately underwent preterm delivery and those who delivered at term; and (4) amniotic fluid concentrations of IL-2, but not other immune mediators, were increased in women with a severely short cervix (≤15 mm) who ultimately delivered preterm compared to those who delivered at term. Conclusions Women with a severely short cervix (≤15 mm) have increased concentrations of pro-inflammatory mediators in the amniotic cavity; yet, these do not translate to changes in the cellular immune response.

Acceptability of a trial of vaginal progesterone for the prevention of preterm birth among HIV-infected women in Lusaka, Zambia: A mixed methods study

Antenatal progesterone prevents preterm birth (PTB) in women with a short cervix or prior PTB in daily vaginal or weekly injectable formulations, respectively. Neither has been tested for the indication of maternal HIV, which is associated with an elevated risk of PTB. The Vaginal Progesterone (VP) Trial was a pilot feasibility study of VP to prevent HIV-related PTB in Lusaka, Zambia. Using mixed methods, we concurrently evaluated the acceptability of the trial and the study product among participants. Over a 1-year period, we enrolled 140 pregnant women living with HIV into a double-masked, placebo-controlled, randomized trial of daily self-administered VP or placebo. We administered an endline questionnaire to all participants and conducted in-depth interviews with 30 participants to assess barriers and facilitators to uptake and retention in the trial and to study product adherence. All interviews were audiotaped, transcribed, translated into English as needed, and independently coded by two analysts to capture emerging themes. Of 131 participants who completed the questionnaire, 128 (98%) reported that nothing was difficult when asked the hardest part about using the study product. When given a hypothetical choice between vaginal and injectable progesterone, 97 (74%) chose vaginal, 31 (24%) injectable, and 3 (2%) stated no preference. Most interviewees reported no difficulties with using the study product; others cited minor side effects and surmountable challenges. Strategies that supported adherence included setting alarms, aligning dosing with antiretrovirals, receiving encouragement from friends and family, sensing a benefit to their unborn baby, and positive feedback from study staff. Participants who reported preference of a vaginal medication over injectable described familiarity with the vaginal product, a fear of needles and resulting pain, and inconvenience of a weekly clinic visit. Those who would prefer weekly injections cited fewer doses to remember. Perceived barriers to study participation included mistrust about the motivations behind research, suspicion of Satanism, and futility or possible harm from a placebo. We report key influences on acceptability of a randomized trial of VP to prevent PTB among HIV-infected women in Zambia, which should inform methods to promote uptake, adherence, and retention in a full-scale trial.

Artificial placenta and womb technology: Past, current, and future challenges towards clinical translation

Extreme prematurity remains a major cause of neonatal mortality and severe long-term morbidity. Current neonatal care is associated with significant morbidity due to iatrogenic injury and developmental immaturity of extreme premature infants. A more physiologic approach, replacing placental function and providing a womb-like environment, is the foundational principle of artificial placenta (AP) and womb (AW) technology. The concept has been studied during the past 60 years with limited success. However, recent technological advancements and a greater emphasis on mimicking utero-placental physiology have improved the success of experimental models, bringing the technology closer to clinical translation. Here, we review the rationale for and history of AP and AW technology, discuss the challenges that needed to be overcome, and compare recent successful models. We conclude by outlining some remaining challenges to be addressed on the path towards clinical translation and opportunities for future research.

Warning of Immortal Time Bias When Studying Drug Safety in Pregnancy: Application to Late Use of Antibiotics and Preterm Delivery

This study aimed to illustrate and account for immortal time bias in pregnancy observational investigations, using the relationship between late use of antibiotics and risk of preterm birth as an example. We conducted a population-based cohort study including 549,082 deliveries between 2007 and 2017 in Lombardy, Italy. We evaluated the risk of preterm births, low birth weight, small for gestational age, and low Apgar score associated with antibiotic dispensing during the third trimester of pregnancy. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CI) of the outcomes, considering the use of antibiotics as time-fixed (with biased classification of exposure person-time) and time-varying (with proper classification of exposure person-time) exposure. There were 23,638 (4.3%) premature deliveries. There was no association between time-fixed exposure to antibiotics and preterm delivery (adjusted HR 0.96; 95% CI 0.92 to 1.01) but an increased risk of preterm birth when time-varying exposure to antibiotics was considered (1.27; 1.21 to 1.34). The same trend was found for low birth weight and low Apgar score. Immortal time bias is a common and sneaky trap in observational studies involving exposure in late pregnancy. This bias could be easily avoided with suitable design and analysis.

Vitamin D during pregnancy and its association with birth outcomes: a Brazilian cohort study

BACKGROUND/OBJECTIVES

Evidence is lacking on how variation in vitamin D concentrations during gestation affects perinatal outcomes. Therefore, we evaluated the association between vitamin D serum concentrations during pregnancy and neonatal outcomes.

METHODS

A prospective cohort of 180 healthy Brazilian pregnant women was followed and plasma 25-hydroxyvitamin [25(OH)D, nmol/L] was measured at 5-13 (baseline), 20-26 and 30-36 gestational weeks. Birth weight (BW), birth length (BL), BW z-scores, BL z-scores, first minute Apgar, small for gestational age (SGA), large for gestational age (LGA) and preterm birth were the outcomes. Multiple linear and Poisson regression models were estimated. Best linear unbiased prediction of random coefficients model was used to determine the association between the mean rate of change in vitamin D during pregnancy concentrations and neonatal outcomes.

RESULTS

Mean (SD) BW was 3300 (600) g, BW z-score 0.34 (1.11), BL 49.3 (3.3) cm, BL z-score 0.44 (1.5), and first minute Apgar score 8.2 (1.4). Prevalence of SGA, LGA and preterm birth were 6%, 18% and 13%, respectively. 25(OH)D was directly associated with the risk of preterm birth at all trimesters. Incidence-rate ratios were 1.02, 1.05 and 1.04 for the 1st, 2nd and 3rd trimester, respectively. Mean rate of change during pregnancy in 25(OH)D was directly associated with BW z-score (β: 0.36, 95% CI 0.07; 0.65), LGA risk (IRR: 1.97, 95% CI 1.07; 3.63) and preterm birth (IRR: 7.35, 95% CI 2.99; 18.07).

CONCLUSIONS

Mean 25(OH)D rate of change during pregnancy was directly associated with BW z-scores, and increased LGA and preterm birth risk.

Essential and toxic elements in human milk concentrate with human milk lyophilizate: A preclinical study

Concentrated human milk (HM-concentrate) can be obtained from the simple and inexpensive method of donated breast milk direct lyophilization. A previous study reported that HM-concentrate contains the adequate amount of main macro- and micronutrients for use as a nutritional resource for preterm infants with very low birth weight admitted to neonatal intensive care units. However, further details need to be elucidated about HM-concentrate composition, particularly its content of essential and potentially toxic trace elements. Therefore, this study aimed to determine the concentration of essential and toxic elements in human milk considered baseline (HM-baseline) and HM-concentrate, as well as to quantify changes in concentration of these elements after the HM concentration process. The concentration of Aluminum, Arsenic, Cadmium, Chromium, Iron, Mercury, Manganese, Nickel, Lead, Selenium, Tin, and Thallium was analyzed by inductively coupled plasma-mass spectrometry (ICP-MS). Moreover, Bayesian linear mixed effect models were applied to estimate the mean difference between HM-baseline and HM-concentrate samples. After comparison (HM-concentrate versus HM-baseline), a significant increase in concentration was observed only for Manganese (0.80 μg/L; 95% CrI [0.16; 1.43]) and Selenium (6.74 μg/L; 95% CrI [4.66; 8.86]), while Lead concentration (-6.13 μg/L; 95% CrI [-8.63; -3.61]) decreased. This study provides latest and reliable information about HM composition. After milk concentration by lyophilization, there was a significant increase only in the essential elements Manganese and Selenium. The essential micronutrient content in HM-concentrate was similar or higher than that in preterm mothers' milk, which suggests it is viable for nutritional support of preterm infants. In addition, the low concentrations of potentially toxic elements in HM-concentrate indicates that it is safe for consumption by premature newborns.

Child Electronic Growth Monitoring System: An innovative and sustainable approach for establishing the Kaduna Infant Development (KID) Study in Nigeria

BACKGROUND

Developing countries bear the burden of childhood stunting but lack resources for cohort studies to develop preventive strategies. To enable future prospective studies, we designed and tested the Child Electronic Growth Monitoring System (CEGROMS) using a readily available electronic data capture platform, the Research Electronic Data Capture (REDCap).

OBJECTIVES

To demonstrate the feasibility of using CEGROMS for data collection for a pilot study for the Kaduna Infant Development (KID) Birth Cohort Study in Nigeria.

METHODS

CEGROMS consists of the data capture form for growth monitoring, a central cloud server, electronic tablets, and desktop computer. We implemented the pilot study in 2017-2019 at the Barau Dikko Teaching Hospital, Kaduna, Nigeria. Odds ratios (OR) and 95% confidence intervals (CI) were calculated for completeness of baseline data (relative to individuals with incomplete data) and completion of follow-up at different time points (relative to individuals with no follow-up visit) by the participant characteristics. Complete data were defined as date of birth, sex, and birthweight recorded at recruitment.

RESULTS

Among 3152 infant records in CEGROMS, 2789 (88.5%) had complete data. Of these, 1905 (68.3%) had at least one follow-up visit. The main determinants of data completeness were health facility delivery (OR 19.17, 95% CI 13.65, 26.92) and tertiary education (OR 3.54, 95% CI 2.69, 4.67). Follow-up was greater for women with tertiary education (OR 1.33, 95% CI 1.06, 1.51 for at least one visit). Maternal education is associated with completeness and follow-up (following adjustments for parity and employment).

CONCLUSIONS

The CEGROMS electronic data collection system enables complete and consistent data collection. The data will enable design of strategies to improve follow-up in the future implementation of the birth cohort study.

Unprecedented reduction in births of very low birthweight (VLBW) and extremely low birthweight (ELBW) infants during the COVID-19 lockdown in Ireland: a 'natural experiment' allowing analysis of data from the prior two decades

BACKGROUND

Aetiology of births involving very low birthweight (VLBW) and extremely low birthweight (ELBW) infants is heterogeneous and preventive strategies remain elusive. Socioenvironmental measures implemented as Ireland's response to the SARS-CoV-2 virus (COVID-19) pandemic represented a national lockdown, and have possibly influenced the health and well-being of pregnant women and unborn infants.

METHODS

Regional trends of VLBW and ELBW infants in one designated health area of Ireland over two decades were analysed. Poisson regression and rate ratio analyses with 95% CI were conducted. Regional data covering most of the lockdown period of 2020 were compared with historical regional and national data and forecasted national figures for 2020.

RESULTS

Poisson regression analysis found that the regional historical VLBW rate per 1000 live births for January to April, 2001-2019 was 8.18 (95% CI 7.21 to 9.29). During January to April 2020, an unusually low VLBW rate of just 2.17 per 1000 live births was observed, reflecting a rate ratio of 3.77 (95% CI 1.21 to 11.75), p=0.022, representing a 73% reduction of VLBW during the first 4 months of 2020 compared with same period for the preceding two decades. There were no ELBW infants admitted to the regional neonatal intensive care unit. National Irish VLBW rate for 2020 is forecasted to be reduced to approximate 400 per 60 000 births compared with the historical 500-600 range.

CONCLUSION

An unprecedented reduction in regional births of VLBW and ELBW infants was observed in Ireland coinciding with the COVID-19 lockdown. Potential determinants of this unique temporal trend possibly reside in the summative socioenvironmental impact of the COVID-19 lockdown. Our findings, if mirrored in other regions that have adopted a lockdown, demonstrate the potential to evaluate these implicated behavioural and socioenvironmental modifiers to positively influence VLBW and ELBW rates globally.

A systematic review on brain injury and altered brain development in moderate-late preterm infants

OBJECTIVES

To provide a systematic review of brain injury and altered brain development in moderate-late preterm (MLPT) infants as compared to very preterm and term infants.

STUDY DESIGN

A systematic search in five databases was performed in January 2020. Original research papers on incidence of brain injury and papers using quantitative data on brain development in MLPT infants were selected. The Johanna Briggs Institute 'Critical Appraisal Checklist for Studies Reporting Prevalence Data' was used for quality appraisal. Data extraction included: imaging modality, incidences of brain injury, brain volumes, 2D-measurements and diffusivity values.

RESULTS

In total, 24 studies were eligible. Most studies had a moderate quality. Twenty studies reported on the incidence of brain injury in MLPT infants. The incidence of intraventricular hemorrhage (IVH) ranged from 0.0% to 23.5% and of white matter injury (WMI) from 0.5% to 10.8%. One study reported the incidence of arterial infarction (0.3%) and none of cerebellar hemorrhage. Eleven studies compared incidences of brain injury between MLPT infants and very preterm or term infants. Five studies reported signs of altered brain development in MLPT infants.

CONCLUSIONS

The incidences of IVH and WMI in MLPT infants varied widely between studies. Other abnormalities were sparsely reported. Evidence regarding a higher or lower incidence of brain injury in MLPT infants compared to very preterm or term infants is weak due to moderate methodological quality of reported studies. There is limited evidence suggesting a difference in brain development between MLPT and term infants.

Retinopathy of Prematurity: How to Prevent the Third Epidemics in Developing Countries

Retinopathy of prematurity (ROP) is vasoproliferative disease affecting preterm infants and is a leading cause of avoidable childhood blindness worldwide. The world is currently experiencing the third epidemic of ROP, where majority of the cases are from middle-income countries. Over 40% of the world's premature infants were born in India, China, Bangladesh, Pakistan, and Indonesia. Together with other neighboring nations, this region has unique challenges in ROP management. Key aspects of the challenges including heavier and more mature infants developing severe ROP. Current strategies include adoption of national screening guidelines, telemedicine, integrating vision rehabilitation and software innovations in the form of artificial intelligence. This review overviews some of these aspects.

Serum apolipoprotein A-II and alpha-2-antiplasmin levels in midtrimester can be used as predictors of preterm delivery

OBJECTIVE

To identify serum protein markers in midtrimester that predict preterm delivery.

METHODS

A retrospective case-control study randomly selected patients that experienced spontaneous preterm birth and healthy control patients that experienced a normal delivery at term. A proteomic analysis was undertaken using the data-independent acquisition method.

RESULTS

A total of 30 singleton pregnant women were randomly selected from 12 800 pregnant women: 15 women had a spontaneous preterm birth (group Y) and 15 age- and body mass index-matched women gave birth at term (group D). All of the patients provided serum at 15-20 weeks of gestation. A total of 39 differentially expressed proteins were identified. Compared with group D, 24 proteins were upregulated and 15 were downregulated in the preterm group Y. Using Kyoto Encyclopedia of Genes and Genomes pathway enrichment, the 24 upregulated proteins were significantly enriched in the complement and coagulation cascade pathways. Search Tool for the Retrieval of Interacting Genes Furthermore (STRING) analysis showed that apolipoprotein A-II (apoA-II) and alpha-2-antiplasmin (α2-AP), two upregulated proteins, were key nodes in the STRING protein-protein network.

CONCLUSIONS

These findings suggest that apoA-II and α2-AP might be new markers for predicting preterm delivery in the midtrimester.

Emerging atypical connectivity networks for processing angry and fearful faces in very preterm born children

Very preterm born (VPT) children are those born before 32/40 weeks' gestational age and comprise 10% of the 15 million babies born prematurely worldwide each year. Due to advancements in neonatal medicine, the survival rate of VPT birth has increased, but few studies have investigated the nonmedical, social-cognitive morbidities that affect these children. In this study, we examined emotional face processing networks in VPT compared to age and sex matched full-term born (FT) children. Magnetoencephalography (MEG) was used to test VPT and FT born children at 6 years (n = 78) and 8 years (n = 83). Children were assessed using an implicit emotion face-processing task. Happy, fearful, and angry faces were presented for 150 ms, but children were asked to respond by button press to the location of a control pixelated image of the face displayed on the side of the screen opposite to the face. Children rated the valence of the images on a five-point scale. Group differences showed that VPT children rated angry faces more positively than their FT peers. VPT children had reduced connectivity for angry and fearful faces at 8 years in networks including regions such as the bilateral amygdala, superior temporal sulci, and anterior cingulate gyrus. Interventions should target both emotion recognition, as well as higher cognitive processes related to emotional control and thinking about one's own emotions.

Basic principles of neonatal bubble CPAP: effects on CPAP delivery and imposed work of breathing when altering the original design

BACKGROUND

The original bubble continuous positive airway pressure (bCPAP) design has wide-bore tubing and a low-resistance interface. This creates a stable airway pressure that is reflected by the submersion depth of the expiratory tubing. Several systems with alterations to the original bCPAP design are now available. Most of these are aimed for use in low-income and middle-income countries and have not been compared with the original design.

OBJECTIVE

We identified three major alterations to the original bCPAP design: (1) resistance of nasal interface, (2) volume of dead space and (3) diameter of expiratory tubing. Our aim was to study the effect of these alterations on CPAP delivery and work of breathing in a mechanical lung model. Dead space should always be avoided and was not further tested.

METHODS

The effect of nasal interface resistance and expiratory tubing diameter was evaluated with simulated breathing in a mechanical lung model without interface leakage. The main outcome was delivered CPAP and imposed work of breathing.

RESULTS

High-resistance interfaces and narrow expiratory tubing increased the work of breathing. Additionally, narrow expiratory tubing resulted in higher CPAP levels than indicated by the submersion depth.

CONCLUSION

Our study shows the significant effect on CPAP delivery and imposed work of breathing when using high-resistance interfaces and narrow expiratory tubing in bCPAP systems. New systems should include low-resistance interfaces and wide-bore tubing and be compared with the original bCPAP. Referring to all systems that bubble as bCPAP is misleading and potentially hazardous.