Planned Repeat Cesarean Section at Term and Adverse Childhood Health Outcomes: A Record-Linkage Study

Duration of rupture of membranes and microbiome transmission to the newborn: A prospective study

OBJECTIVE

To assess whether labour variables (i.e. individuals characteristics, labour characteristics and medical interventions) impact maternal and newborn microbiomes.

DESIGN

Prospective monocentric study.

SETTING

Saint-Joseph Hospital tertiary maternity unit, in Paris, France.

POPULATION

All consecutive primiparous women with a physiological pregnancy and term labour from 15 April to 1 June 2017.

METHODS

16S ribosomal RNA gene sequencing of the maternal vaginal, newborn skin and newborn oral microbiomes from 58 mother-baby dyads.

MAIN OUTCOME MEASURES

Analysis of the effects of 19 labour variables on the composition and diversity of these microbiomes.

RESULTS

The 19 labour variables explained a significant part of the variability in the vaginal, newborn oral and skin microbiomes (44%-67%). Strikingly, duration of rupture of membranes was the single factor that explained the greatest variability (adjusted R2: 7.7%-8.4%, p ≤ 0.002) and conditioned, by itself, the compositions of the three microbiomes under study. Long duration of rupture of membranes was specifically associated with a lower relative abundance of the Lactobacillus genus (1.7-fold to 68-fold reduction, p < 0.0001) as well as an increase in microbiome diversity, including genera implicated in nosocomial infections. The effects of duration of rupture of membranes were also present in newborns delivered by non-elective caesarean section.

CONCLUSIONS

Maternal and newborn microbiomes were greatly affected by labour variables. Duration of rupture of membranes, even in non-elective caesarean sections, should be considered in epidemiological and microbiological studies, as well as in vaginal seeding practices.

Mode of birth in subsequent pregnancy when first birth was vacuum extraction or second stage cesarean section at a tertiary referral hospital in Uganda

INTRODUCTION

The trends of increasing use of cesarean section (CS) with a decrease in assisted vaginal birth (vacuum extraction or forceps) is a major concern in health care systems all over the world, particularly in low-resource settings. Studies show that a first birth by CS is associated with an increased risk of repeat CS in subsequent births. In addition, CS compared to assisted vaginal birth (AVB), attracts higher health service costs. Resource-constrained countries have low rates of AVB compared to high-income countries. The aim of this study was to compare mode of birth in the subsequent pregnancy among women who previously gave birth by vacuum extraction or second stage CS in their first pregnancy at Mulago National Referral Hospital, Uganda.

METHODS

This was a retrospective cohort study that involved interviews of 81 mothers who had a vacuum extraction or second stage CS in their first pregnancy at Mulago hospital between November 2014 to July 2015. Mode of birth in the subsequent pregnancy was compared using Chi-2 square test and a Fisher's exact test with a 0.05 level of statistical significance.

RESULTS

Higher rates of vaginal birth were achieved among women who had a vacuum extraction (78.4%) compared to those who had a second stage CS in their first pregnancy (38.6%), p < 0.001.

CONCLUSIONS AND RECOMMENDATIONS

Vacuum extraction increases a woman's chance of having a subsequent spontaneous vaginal birth compared to second stage CS. Health professionals need to continue to offer choice of vacuum extraction in the second stage of labor among laboring women that fulfill its indication. This will help curb the up-surging rates of CS.

Association of cesarean section with asthma in children/adolescents: a systematic review and meta-analysis based on cohort studies

BACKGROUND

Whether cesarean section (CS) is a risk factor for asthma in offspring is controversial. The purpose of this study was to investigate the association between CS and asthma in children/adolescents.

METHODS

Pubmed, Embase, Web of Science, and Cochrane Library electronic databases were searched for cohort studies on the relationship between mode of delivery and asthma in children/adolescents up to February 2023. Birth via CS was considered an exposure factor. Asthma incidence was taken as a result.

RESULTS

Thirty-five cohort studies (thirteen prospective and twenty-two retrospective cohort studies) were included. The results showed that the incidence of asthma was higher in CS offspring (odds ratio (OR) = 1.18, P < 0.001) than in the vaginal delivery (VD) group. Partial subgroup analyses showed a higher incidence of asthma in female offspring born via CS (OR = 1.26, P < 0.001) compared with the VD group, while there was no difference in males (OR = 1.07, P = 0.325). Asthma incidence was higher in CS offspring than in the VD group in Europe (OR = 1.20, P < 0.001), North America (OR = 1.15, P < 0.001), and Oceania (OR = 1.06, P = 0.008). This trend was not found in the Asian population (OR = 1.17, P = 0.102). The incidence of atopic asthma was higher in offspring born via CS (OR = 1.14, P < 0.001) compared to the VD group. The CS group had a higher incidence of persistent asthma, but the difference did not reach statistical significance (OR = 1.15, P = 0.063).

CONCLUSION

In this meta-analysis, CS may be a risk factor for asthma in offspring children/adolescents compared with VD. The relationship between CS and asthma was influenced by sex and region.

Short-term and long-term effects of cesarean section on asthma and wheezing: A cohort study and meta-analysis

OBJECTIVE

To describe the short-term and long-term effects of cesarean section on childhood asthma and wheezing.

METHOD

Firstly, in the cohort study, 6640 infants were included in the cohort baseline from January 2018 to December 2019, in which 6501 children completed the follow-up study for respiratory diseases at age 2 years. The effect of cesarean section on asthma and wheezing was estimated by the logistic regression model. Secondly, we conducted a meta-analysis of studies with outcomes of childhood asthma and wheezing under 2 years of age and over 2 years of age, respectively, to investigate the short-term and long-term effects of cesarean section on asthma and wheezing.

RESULTS

In our cohort study, the cumulative incidence of asthma and wheezing was 1.3% (84/6501). 45.5% of children (2961/6501) were born by cesarean section. The adjusted odds ratio for the effect of cesarean section on asthma and wheezing in children under 2 years of age was 1.14 (95%CI 0.73-1.78). Combining previous studies (outcomes of asthma and wheezing under 2 years of age) with our results for a meta-analysis, the odds ratio was 1.15 (95%CI 1.05-1.25, I² = 46.82%). Meanwhile, cesarean section had a long-term effect on asthma and wheezing in the child population over 2 years of age (OR = 1.17, 95%CI 1.11-1.24, P < 0.001, I² = 79.38%).

CONCLUSION

Cesarean section had a short-term effect on asthma and wheezing before the age of 2, in addition, the long-term effect of cesarean section on asthma and wheezing persisted in the child population (under 18).

Early childhood educational outcomes of children associated with vaginal birth after cesarean delivery

BACKGROUND

Rates of vaginal birth after cesarean delivery have decreased and cesarean delivery rates have increased in the last 2 decades. Evidence on short-term neonatal outcomes is available, but data on long-term childhood outcomes following vaginal birth after cesarean delivery are insufficient. Long-term childhood outcome data are essential in decision-making regarding mode of delivery.

OBJECTIVE

This study aimed to evaluate the association between delivery mode and long-term educational outcomes of the children of pregnant individuals with a previous cesarean delivery.

STUDY DESIGN

This was a retrospective cohort study linking Rhode Island third-grade education data from 2014 to 2017 to birth certificate data. Data were obtained from a statewide database using Department of Education data, and were linked to Department of Health birth certificate data. Participants were children of multiparous women who were term, singleton births without congenital anomalies. Children delivered by primary cesarean delivery were excluded. The exposure was mode of delivery classified as vaginal birth after cesarean delivery, repeated cesarean delivery, or repeated vaginal birth. The primary outcome was children's third-grade reading and math proficiency. Bivariate analyses were conducted to assess differences in demographic variables. Bivariable and multivariable log-binomial regression was used to examine the association between subject proficiency and predictors including mode of delivery, maternal education, sex, child race or ethnicity, and lunch subsidy.

RESULTS

Of the 10,923 children who met the inclusion criteria, 2.0% were delivered by vaginal birth after cesarean delivery, 22.0% by repeated cesarean delivery, and 76.0% by repeated vaginal delivery. After adjustment for confounders, there was no difference in reading proficiency (adjusted risk ratio, 0.98; 95% confidence interval, 0.84-1.15) or math proficiency (adjusted risk ratio, 0.99; 95% confidence interval, 0.84-1.15) between those born by vaginal birth after cesarean delivery and those born by repeated cesarean delivery. There was no difference found in either proficiency between children born by repeated vaginal birth and those born by repeated cesarean delivery (reading: adjusted risk ratio, 0.97; 95% confidence interval, 0.93-1.01; math: adjusted risk ratio, 0.97; 95% confidence interval, 0.92-1.02).

CONCLUSION

In comparison with repeated cesarean delivery, both vaginal birth after cesarean delivery and repeated vaginal birth were not associated with differences in educational outcomes. This may aid in counseling about long-term safety outcomes regarding vaginal birth after cesarean delivery and may assist in shared decision-making when selecting between trial of labor after cesarean delivery and repeated cesarean delivery.

Planned mode of birth after previous cesarean section: A structured review of the evidence on the associated outcomes for women and their children in high-income setting

In many high-income settings policy consensus supports giving pregnant women who have had a previous cesarean section a choice between planning an elective repeat cesarean section (ERCS) or planning a vaginal birth after previous cesarean (VBAC), provided they have no contraindications to VBAC. To help women make an informed decision regarding this choice, clinical guidelines advise women should be counseled on the associated risks and benefits. The most recent and comprehensive review of the associated risks and benefits of planned VBAC compared to ERCS in high-income settings was published in 2010 by the US Agency for Healthcare Research and Quality (AHRQ). This paper describes a structured review of the evidence in high-income settings that has been published since the AHRQ review and the literature in high-income settings that has been published since 1980 on outcomes not included in the AHRQ review. Three databases (MEDLINE, EMBASE, and PsycINFO) were searched for relevant studies meeting pre-specified eligible criteria, supplemented by searching of reference lists. Forty-seven studies were identified as meeting the eligibility criteria and included in the structured review. The review suggests that while planned VBAC compared to ERCS is associated with an increased risk of various serious birth-related complications for both the mother and her baby, the absolute risk of these complications is small for either birth approach. The review also found some evidence that planned VBAC compared to ERCS is associated with benefits such as a shorter length of hospital stay and a higher likelihood of breastfeeding. The limited evidence available also suggests that planned mode of birth after previous cesarean section is not associated with the child’s subsequent risk of experiencing adverse neurodevelopmental or health problems in childhood. This information can be used to manage and counsel women with previous cesarean section about their subsequent birth choices. Collectively, the evidence supports existing consensus that there are risks and benefits associated with both planned VBAC and ERCS, and therefore women without contraindications to VBAC should be given an informed choice about planned mode of birth after previous cesarean section. However, further studies into the longer-term effects of planned mode of birth after previous cesarean section are needed along with more research to address the other key limitations and gaps that have been highlighted with the existing evidence.

A complete guide to human microbiomes: Body niches, transmission, development, dysbiosis, and restoration

Humans are supra-organisms co-evolved with microbial communities (Prokaryotic and Eukaryotic), named the microbiome. These microbiomes supply essential ecosystem services that play critical roles in human health. A loss of indigenous microbes through modern lifestyles leads to microbial extinctions, associated with many diseases and epidemics. This narrative review conforms a complete guide to the human holobiont-comprising the host and all its symbiont populations- summarizes the latest and most significant research findings in human microbiome. It pretends to be a comprehensive resource in the field, describing all human body niches and their dominant microbial taxa while discussing common perturbations on microbial homeostasis, impacts of urbanization and restoration and humanitarian efforts to preserve good microbes from extinction.

The First 1000 Days: Assembly of the Neonatal Microbiome and Its Impact on Health Outcomes

Early life microbial colonization is critical for the development of the immune system, postnatal growth, and long-term health and disease. The dynamic and nascent microbiomes of children are highly individualized and are characterized by low bacterial diversity. Any disruptions in microbial colonization can contribute to shifts in normal microbial colonization that persist past the first 1000 days of life and result in intestinal dysbiosis. Here, we focus on microbiome-host interactions during fetal, newborn, and infant microbiome development. We summarize the roles of bacterial communities in fetal development and adverse health outcomes due to dysbiosis. We also discuss how internal and external factors program the microbiome's metabolic machinery as it evolves into an adult-like microbiome. Finally, we discuss the limits of current studies and future directions. Studies on the early-life microbiome will be critical for a better understanding of childhood health and diseases, as well as restorative methods for the prevention and treatment of diseases in adulthood.

Caesarean delivery and risk of childhood asthma development: meta-analysis

Introduction

Several studies indicate that delivery by caesarean section may be one of the risk factors for the development of childhood asthma.

Aim

A meta-analysis was carried out to establish the relationship between delivery by caesarean section and asthma in children.

Material and methods

After a review of bibliographic databases, 41 articles were obtained and 12 of which were accepted for further analysis. The odds ratios (OR) included in the analysis were specified on the basis of data from the presented studies or were calculated using reported prevalence. The analysis took into account unadjusted OR. The heterogeneity of results was assessed using the χ² test, determining p < 0.05 as the level of significance. The analysis was performed using Statistica 13.3 and kit 4.0.67.

Results

Caesarean delivery was associated with an increased risk of development of childhood asthma (OR = 1.41); however, significant heterogeneity of results was demonstrated. A significantly higher risk of asthma was found in children born by caesarean section in the case where the disease was confirmed in a questionnaire-based study (OR = 1.26, 95% CI: 1.05-1.5), and the results of that study were homogeneous.

Conclusions

In the case of the diagnosis of asthma declared by parents in the questionnaire-based study, a significantly higher risk of disease occurrence was observed in children born by caesarean section. Due to the significant heterogeneity of the results of the studies, it cannot be clearly stated that caesarean delivery is a risk factor for the development of bronchial asthma.

Associations between cesarean delivery and child mortality: A national record linkage longitudinal study of 17.8 million births in Brazil

BACKGROUND

There is an increasing use of cesarean delivery (CD) based on preference rather than on medical indication. However, the extent to which nonmedically indicated CD benefits or harms child survival remains unclear. Our hypothesis was that in groups with a low indication for CD, this procedure would be associated with higher child mortality and in groups with a clear medical indication CD would be associated with improved child survival chances.

METHODS AND FINDINGS

We conducted a population-based cohort study in Brazil by linking routine data on live births between January 1, 2012 and December 31, 2018 and assessing mortality up to 5 years of age. Women with a live birth who contributed records during this period were classified into one of 10 Robson groups based on their pregnancy and delivery characteristics. We used propensity scores to match CD with vaginal deliveries (1:1) and prelabor CD with unscheduled CD (1:1) and estimated associations with child mortality using Cox regressions. A total of 17,838,115 live births were analyzed. After propensity score matching (PSM), we found that live births to women in groups with low expected frequencies of CD (Robson groups 1 to 4) had a higher death rate up to age 5 years if they were born via CD compared with vaginal deliveries (HR = 1.25, 95% CI: 1.22 to 1.28; p < 0.001). The relative rate was greatest in the neonatal period (HR = 1.39, 95% CI: 1.34 to 1.45; p < 0.001). There was no difference in mortality rate when comparing offspring born by a prelabor CD to those born by unscheduled CD. For the live births to women with a CD in a prior pregnancy (Robson group 5), the relative rates for child mortality were similar for those born by CD compared with vaginal deliveries (HR = 1.05, 95% CI: 1.00 to 1.10; p = 0.024). In contrast, for live births to women in groups with high expected rates of CD (Robson groups 6 to 10), the child mortality rate was lower for CD than for vaginal deliveries (HR = 0.90, 95% CI: 0.89 to 0.91; p < 0.001), particularly in the neonatal period (HR = 0.84, 95% CI: 0.83 to 0.85; p < 0.001). Our results should be interpreted with caution in clinical practice, since relevant clinical data on CD indication were not available.

CONCLUSIONS

In this study, we observed that in Robson groups with low expected frequencies of CD, this procedure was associated with a 25% increase in child mortality. However, in groups with high expected frequencies of CD, the findings suggest that clinically indicated CD is associated with a reduction in child mortality.

Vaginal microbiome topic modeling of laboring Ugandan women with and without fever

The composition of the maternal vaginal microbiome influences the duration of pregnancy, onset of labor, and even neonatal outcomes. Maternal microbiome research in sub-Saharan Africa has focused on non-pregnant and postpartum composition of the vaginal microbiome. Here we aimed to illustrate the relationship between the vaginal microbiome of 99 laboring Ugandan women and intrapartum fever using routine microbiology and 16S ribosomal RNA gene sequencing from two hypervariable regions (V1–V2 and V3–V4). To describe the vaginal microbes associated with vaginal microbial communities, we pursued two approaches: hierarchical clustering methods and a novel Grades of Membership (GoM) modeling approach for vaginal microbiome characterization. Leveraging GoM models, we created a basis composed of a preassigned number of microbial topics whose linear combination optimally represents each patient yielding more comprehensive associations and characterization between maternal clinical features and the microbial communities. Using a random forest model, we showed that by including microbial topic models we improved upon clinical variables to predict maternal fever. Overall, we found a higher prevalence of Granulicatella, Streptococcus, Fusobacterium, Anaerococcus, Sneathia, Clostridium, Gemella, Mobiluncus, and Veillonella genera in febrile mothers, and higher prevalence of Lactobacillus genera (in particular L. crispatus and L. jensenii), Acinobacter, Aerococcus, and Prevotella species in afebrile mothers. By including clinical variables with microbial topics in this model, we observed young maternal age, fever reported earlier in the pregnancy, longer labor duration, and microbial communities with reduced Lactobacillus diversity were associated with intrapartum fever. These results better defined relationships between the presence or absence of intrapartum fever, demographics, peripartum course, and vaginal microbial topics, and expanded our understanding of the impact of the microbiome on maternal and potentially neonatal outcome risk.

Planned mode of birth after previous caesarean section and special educational needs in childhood: a population-based record linkage cohort study

Objective

To investigate the association between planned mode of birth after previous caesarean section and a child’s risk of having a record of special educational needs (SENs).

Design

Population‐based cohort study.

Setting

Scotland.

Population

A cohort of 44 892 singleton children born at term in Scotland between 2002 and 2011 to women with one or more previous caesarean sections.

Methods

Linkage of Scottish national health and education data sets.

Main outcome measures

Any SENs and specific types of SEN recorded when a child was aged 4–11 years and attending a Scottish primary or special school.

Results

Children born following planned vaginal birth after previous caesarean (VBAC) compared with elective repeat caesarean section (ERCS) had a similar risk of having a record of any SENs (19.24 versus 17.63%, adjusted risk ratio aRR 1.04, 95% CI 0.99–1.09) or specific types of SEN. There was also little evidence that planned VBAC with or without labour induction compared with ERCS was associated with a child’s risk of having a record of any SENs (21.42 versus 17.63%, aRR 1.09, 95% CI 1.01–1.17 and 18.78 versus 17.63%, aRR 1.03, 95% CI 0.98–1.08, respectively) or most types of SEN. However, an increased risk of sensory impairment was seen for planned VBAC with labour induction compared with ERCS (1.18 versus 0.78%, risk difference 0.4%, adjusted odds ratio aOR 1.60, 95% CI 1.09–2.34).

Conclusions

This study provides little evidence of an association between planned mode of birth after previous caesarean and SENs in childhood beyond a small absolute increased risk of sensory impairment seen for planned VBAC with labour induction. This finding may be the result of performing multiple comparisons or residual confounding. The findings provide valuable information to manage and counsel women with previous caesarean section concerning their future birth choices.

Tweetable abstract

There is little evidence planned mode of birth after previous caesarean section is associated with special educational needs in childhood.

There is little evidence planned mode of birth after previous caesarean section is associated with special educational needs in childhood.

Intrapartum Cesarean Delivery Due to Nonreassuring Fetal Heart Rate and the Risk of Pediatric Infectious Morbidity-related Hospitalizations of the Offspring

OBJECTIVES

One of the most common indications for intrapartum cesarean delivery (CD) is nonreassuring fetal heart rate (NRFHR) patterns. We aimed to study the long-term effect of CD due to NRFHR on the risk for subsequent childhood infectious morbidity-related hospitalizations of the offspring.

STUDY DESIGN

A population-based cohort study was performed, comparing total and different subtypes of infectious morbidity-related pediatric hospitalizations among offspring born by CD due to NRFHR versus labor dystocia (failure of labor to progress during the 1st or 2nd stage). The analysis included all singletons born between the years 1999-2014 at a single tertiary regional medical center. Infectious-related morbidities included hospitalizations involving a predefined set of International Classification of Diseases, 9th revision codes, as recorded in hospital computerized files. Infants with congenital malformations, multiple gestations, vaginal deliveries and vacuum failure were excluded from the analysis. Perinatal mortality cases were excluded from the long-term analysis. A Kaplan-Meier survival curve was used to compare the cumulative morbidity, and a Cox proportional hazards model was constructed to adjust for confounders.

RESULTS

The study population included 9956 newborns who met inclusion criteria; among them, 5810 (58%) were born by CD due to NRFHR, and 4146 (42%) were born via CD following labor dystocia with normal fetal heart rate (comparison group). Offspring born following NRFHR had higher rates of infectious morbidity-related hospitalizations (11.4% vs. 9.1%; odds ratio, 1.3; 95% confidence interval, 1.1-1.5; P < 0.01; Kaplan-Meier survival curve P < 0.01). The association remained significant and independent while adjusting for gestational age, maternal age and comorbidities, using a Cox proportional hazards model (adjusted hazard ratio, 1.3; 95% confidence interval, 1.2-1.4; P < 0.01).

CONCLUSIONS

In our population, CD due to NRFHR is a risk factor for pediatric infectious morbidity-related hospitalizations of the offspring.

The Challenges and Achievements in the Implementation of the Natural Childbirth Instruction Program: A Qualitative Study

Background

The natural childbirth instruction program, which aims to reduce the cesarean section (C-section) rates in the country and pay attention to demographic policies, has achieved significant accomplishments in the short time span since it was implemented throughout the country. In the present study, the advantages and challenges of the implementation of this program have been analyzed.

Materials and Methods

This qualitative study carried out with the participation of 32 knowledgeable individuals who were selected using purposeful sampling and snowball sampling methods among the personnel of Kerman University of Medical Sciences, and it's affiliated educational (university) hospital. The data were collected through semi-structured interviews based on the research objectives, review of texts, and experts' experiences. Data analysis was performed using content analysis method in MaxQDA software.

Results

Data analysis provided the 5 main categories of implementation instructions' strengths, implementation instructions' defects, implementation instructions' achievements, implementation instructions' challenges and threats, and suggestions.

Conclusions

Accountability in the system that provides health care services for pregnant mothers in public hospitals has been created through the implementation of the natural childbirth promotion package. If managerial barriers and executive and legal inefficiencies are followed up and suitable measures are taken for solving the intra-system conflicts, we can hope that the package, which has been one of the most serious efforts made by the Ministry of Health over the past decades to reduce cesarean delivery, will achieve significant accomplishments.

Elective Caesarean Delivery Associated with Infant Hospitalisation for Intestinal But Not Respiratory Infection

OBJECTIVES

We assessed the impact of caesarean delivery on offspring respiratory and intestinal infection.

METHODS

Data were extracted from all live births (n = 429,058) occurring in the Australian state of Queensland between January 2009 and December 2015, and followed for 12 months. Births were categorised as either non-medically indicated caesarean or vaginal delivery and each offspring had a record (present/absent) of respiratory and intestinal infection hospitalisation for each month from birth to 12 months.

RESULTS

Infants delivered by non-medically indicated caesarean were more likely to experience respiratory infection [OR = 1.51 (1.15, 1.99)] and intestinal infection [OR = 1.74 (1.19, 2.55)] than those born by vaginal delivery. In the propensity score weighted analyses the estimate for respiratory infection was similar but non-significant [OR = 1.52 (0.99, 2.31)], while the association with intestinal infection strengthened [OR = 2.21 (1.25, 3.89)].

CONCLUSIONS FOR PRATICE

Our findings provide strong evidence for a specific and clinically meaningful link between non-medically indicated caesarean delivery and infant intestinal infection.

Is cesarean section delivery associated with autism spectrum disorder?

Objectives:

To investigate a correlation between birth by caesarean section and autism spectrum disorder (ASD).

Methods:

A case-control study with a case to control ratio of 1:2 was performed in Al-Madina Al-Munawarah city, Kingdom of Saudi Arabia during the year 2016. The cases were selected according to the eligibility criteria and children attending a well-baby clinic in the same hospital, were chosen as the control group subjects. Data was collected from the medical records and an interview-based questionnaire was administered to the mothers. The chi-square test was used for bivariate analysis and logistic regression to estimate the crude and adjusted odds ratios (ORs).

Results:

Eighty-seven cases of ASD and 174 control group subjects were included in the current study. Approximately 39% (n=34) of the 87 children with ASD were delivered by cesarean section compared to 21% (n=36) of the 174 children in the control group. After adjusting for potentially confounding factors, the adjusted OR was 2.9 (95% confidence interval [CI]: 1.57-5.35).

Conclusion:

An association between delivery by cesarean section and ASD was found in this study, in support of the findings of other studies. It is recommended that preventive measures are adopted to avoid unnecessary cesarean sections.

Inflammatory Bowel Diseases: Host-Microbial-Environmental Interactions in Dysbiosis

Crohn's Disease (CD) and Ulcerative Colitis (UC) are world-wide health problems in which intestinal dysbiosis or adverse functional changes in the microbiome are causative or exacerbating factors. The reduced abundance and diversity of the microbiome may be a result of a lack of exposure to vital commensal microbes or overexposure to competitive pathobionts during early life. Alternatively, many commensal bacteria may not find a suitable intestinal niche or fail to proliferate or function in a protective/competitive manner if they do colonize. Bacteria express a range of factors, such as fimbriae, flagella, and secretory compounds that enable them to attach to the gut, modulate metabolism, and outcompete other species. However, the host also releases factors, such as secretory IgA, antimicrobial factors, hormones, and mucins, which can prevent or regulate bacterial interactions with the gut or disable the bacterium. The delicate balance between these competing host and bacteria factors dictates whether a bacterium can colonize, proliferate or function in the intestine. Impaired functioning of NOD2 in Paneth cells and disrupted colonic mucus production are exacerbating features of CD and UC, respectively, that contribute to dysbiosis. This review evaluates the roles of these and other the host, bacterial and environmental factors in inflammatory bowel diseases.

An in-depth survey of the microbial landscape of the walls of a neonatal operating room

Bacteria found in operating rooms (ORs) might be clinically relevant since they could pose a threat to patients. In addition, C-sections operations are performed in ORs that provide the first environment and bacterial exposure to the sterile newborns that are extracted directly from the uterus to the OR air. Considering that at least one third of neonates in the US are born via C-section delivery (and more than 50% of all deliveries in some countries), understanding the distribution of bacterial diversity in ORs is critical to better understanding the contribution of the OR microbiota to C-section- associated inflammatory diseases. Here, we mapped the bacteria contained in an OR after a procedure was performed; we sampled grids of 60x60 cm across walls and wall-adjacent floors and sequenced the V4 region of 16S rRNA gene from 260 samples. The results indicate that bacterial communities changed significantly (ANOSIM, p-value < 0.001) with wall height, with an associated reduction of alpha diversity (t-test, p-value <0.05). OR walls contained high proportions of Proteobacteria, Firmicutes, and Actinobacteria, with Proteobacteria and Bacteroidetes being the highest in floors and lowest in the highest wall sites. Members of Firmicutes, Deinococcus-thermus, and Actinobacteria increased with wall height. Source-track analysis estimate that human skin is the major source contributing to bacterial composition in the OR walls, with an increase of bacteria related to human feces in the lowest walls and airborne bacteria in the highest wall sites. The results show that bacterial exposure in ORs varies spatially, and evidence exposure of C-section born neonates to human bacteria that remain on the floors and walls, possibly accumulated from patients, health, and cleaning staff.

Outcomes of trial of labor after cesarean birth by provider type in low-risk women

BACKGROUND

One approach to decreasing the cesarean birth rate in the United States is to increase the availability of birth attendants, including certified nurse-midwives (CNMs), who offer trial of labor after cesarean (TOLAC). We examined associations between provider type and mode of birth for women attempting vaginal birth after cesarean (VBAC).

METHODS

We performed a retrospective cohort study at a United States academic medical center using prospectively-collected data (2005-2012). We included healthy women with term singleton vertex pregnancies after one or two prior cesareans who were managed by obstetricians or CNMs. We assessed unplanned cesarean birth by provider type using univariate and logistic regression and examined labor interventions and predicted VBAC success.

RESULTS

Overall VBAC success was 88% for 502 included patients. Unplanned cesarean rates were similar by provider type. Black race, no prior VBAC, recurring clinical indication for cesarean, labor augmentation/induction, and any Pitocin use were associated with increased unplanned cesarean. Higher parity and early-term gestational age at delivery were associated with decreased unplanned cesarean. Postpartum hemorrhage and composite maternal morbidity were increased with unplanned cesarean, but there was no difference in neonatal outcome by mode of delivery or provider type. Obstetricians had slightly higher composite adverse maternal outcomes. Nomogram-predicted VBAC success but not provider type was associated with unplanned cesarean.

CONCLUSIONS

Unplanned cesarean was similar for patients attempting labor after cesarean managed by midwives or obstetricians. Increasing the number of CNMs who manage TOLAC may help decrease the high rate of cesareans.

The role of Caesarean section in childhood asthma

OBJECTIVE

As indicated by previous studies, children born via Caesarean section may have an increased risk of developing asthma compared with those born via vaginal delivery. The aim of this study is to assess the association between a Caesarean section and the risk of childhood asthma. Methods: This was a case-control study carried out in Basrah, Iraq including 952 children aged 3-12 years. Four hundred and seven asthmatic cases and a control group of 545 age-matched non-asthmatic children were enrolled. Binary logistic regression was used to assess the relationship between asthma and birth via Caesarean section.

RESULTS

The mean age of the children was 6.7±2.5 years. Two-hundred eighty-three children (29.7%) were delivered via Caesarean section. The binary logistic regression analysis showed that delivery via Caesarean section was found to be an independent significant risk factor for asthma (OR=3.37; 95% CI=1.76-6.46; p<0.001). In addition, many other risk factors were found to be significant predictors of asthma, including bottlefeeding (OR=27.29; 95% CI=13.54-54.99; p<0.001) and low birth weight (OR=16.7; 95% CI=6.97-37.49; p<0.001).

CONCLUSION

Caesarean section is significantly associated with an increased risk of childhood asthma.

Maternal milk and fecal microbes guide the spatiotemporal development of mucosa-associated microbiota and barrier function in the porcine neonatal gut

BACKGROUND

The early-life microbiota exerts a profound and lifelong impact on host health. Longitudinal studies in humans have been informative but are mostly based on the analysis of fecal samples and cannot shed direct light on the early development of mucosa-associated intestinal microbiota and its impact on GI function. Using piglets as a model for human infants, we assess here the succession of mucosa-associated microbiota across the intestinal tract in the first 35 days after birth.

RESULTS

Although sharing a similar composition and predicted functional profile at birth, the mucosa-associated microbiome in the small intestine (jejunum and ileum) remained relatively stable, while that of the large intestine (cecum and colon) quickly expanded and diversified by day 35. Among detected microbial sources (milk, vagina, areolar skin, and feces of sows, farrowing crate, and incubator), maternal milk microbes were primarily responsible for the colonization of the small intestine, contributing approximately 90% bacteria throughout the first 35 days of the neonatal life. Although maternal milk microbes contributed greater than 90% bacteria to the large intestinal microbiota of neonates upon birth, their presence gradually diminished, and they were replaced by maternal fecal microbes by day 35. We found strong correlations between the relative abundance of specific mucosa-associated microbes, particularly those vertically transmitted from the mother, and the expression levels of multiple intestinal immune and barrier function genes in different segments of the intestinal tract.

CONCLUSION

We revealed spatially specific trajectories of microbial colonization of the intestinal mucosa in the small and large intestines, which can be primarily attributed to the colonization by vertically transmitted maternal milk and intestinal microbes. Additionally, these maternal microbes may be involved in the establishment of intestinal immune and barrier functions in neonates. Our findings strengthen the notion that studying fecal samples alone is insufficient to fully understand the co-development of the intestinal microbiota and immune system and suggest the possibility of improving neonatal health through the manipulation of maternal microbiota.

Risk of Type 1 Diabetes in the Offspring Born through Elective or Non-elective Caesarean Section in Comparison to Vaginal Delivery: a Meta-Analysis of Observational Studies

BACKGROUND

Caesarean section (CS) has been associated with an increased risk of type 1 diabetes (T1D). The lack of exposure to maternal vaginal and anal microbiome and bypassing the labor process often observed in elective CS may affect neonatal immune system development. This study aims to summarize the effects of elective and non-elective CS on T1D risk in the offspring.

METHODS

A systematic literature search was conducted online for publications providing data on elective and non-elective CS with T1D diagnosis in children and young adults, followed by a meta-analysis from selected studies. Newcastle-Ottawa Scale and GRADEpro tool were applied for quality analysis.

RESULTS

Nine observational studies comprising over 5 million individuals fulfilled the inclusion criteria. Crude OR estimates showed a 12% increased T1D risk from elective CS compared to vaginal delivery with significant heterogeneity. Adjusted ORs from seven studies did not show T1D risk differences from either CS category, and heterogeneity was detected between studies. Separate analysis of cohort and case-control studies reduced the heterogeneity and revealed a slight increase in T1D risk associated with elective CS in cohort studies (adjusted OR = 1.12 (1.01-1.24)), and a higher increased risk associated with non-elective CS in case-control studies (adjusted OR = 1.19 (1.06-1.34)).

CONCLUSION

Summarized crude risk estimates showed a small increased T1D risk in children and young adults born through elective CS compared to vaginal delivery, but with significant heterogeneity. Adjusted risk estimates by study design indicated a slightly increased T1D risks associated with elective or non-elective CS.

The association between caesarean section and childhood asthma: an updated systematic review and meta-analysis

Background

Investigating the association between caesarean section (SC) and childhood asthma has shown contradictory results in different studies. The present study was conducted to determine the association between SC and childhood asthma.

Material and method

The present study was conducted based on the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. All the steps of the study were conducted independently by two reviewers from the inception until February 1, 2019. In case of disagreement, the third reviewer resolved it. We searched international online databases, including Scopus, Cochrane Library, PubMed/Medline, Embase, Web of Science (ISI), Science Direct, and Google scholar. The results of studies were combined using random effects model, and heterogeneity was measured through I² index and Cochran’s Q test. Comprehensive Meta-Analysis Software was used for meta-analysis. The significance level of all tests was considered to be P < 0.05.

Results

The heterogeneity rate was high (I² = 67.31%, P < 0.001) in 37 studies. The results showed that SC increased the risk of childhood asthma (RR (relative risk) = 1.20 [95% CI 1.15–1.25, P < 0.001]). The association between emergency and elective SC and childhood asthma was significant with RR of 1.18 (95% CI 1.07–1.29, P < 0.001) in 13 studies and 1.23 (95% CI 1.20–1.26, P < 0.001) in 13 studies, respectively. The subgroup analysis for RR of childhood asthma in SC indicated that study design (P = 0.306), prospective/retrospective studies (P = 0.470), quality of studies (P = 0.514), continent (P = 0.757), age of diagnosis (P = 0.283) and year of publication (P = 0.185) were not effective in the heterogeneity of studies. Sensitivity analysis by removing one study at a time indicated that the overall estimate is robust.

Conclusion

According to the meta-analysis, SC (overall, elective, and emergency) increased the risk of childhood asthma. Therefore, it is hoped that developing clinical guidelines and implementing appropriate management plans would diminish the risk of asthma.

Factors associated with successful vaginal birth after a cesarean section: a systematic review and meta-analysis

Background

Evidence for the relationship between maternal and perinatal factors and the success of vaginal birth after cesarean section (VBAC) is conflicting. We aimed to systematically analyze published data on maternal and fetal factors for successful VBAC.

Methods

A comprehensive search of Medline, Embase, and the Cumulative Index to Nursing and Allied Health Literature, from each database’s inception to March 16, 2018. Observational studies, identifying women with a trial of labor after one previous low-transverse cesarean section were included. Two reviewers independently abstracted the data. Meta-analysis was performed using the random-effects model. Risk of bias was assessed by the Newcastle-Ottawa Scale.

Results

We included 94 eligible observational studies (239,006 pregnant women with 163,502 VBAC). Factors were associated with successful VBAC with the following odds ratios (OR;95%CI): age (0.92;0.86–0.98), obesity (0.50;0.39–0.64), diabetes (0.50;0.42–0.60), hypertensive disorders complicating pregnancy (HDCP) (0.54;0.44–0.67), Bishop score (3.77;2.17–6.53), labor induction (0.58;0.50–0.67), macrosomia (0.56;0.50–0.64), white race (1.39;1.26–1.54), previous vaginal birth before cesarean section (3.14;2.62–3.77), previous VBAC (4.71;4.33–5.12), the indications for the previous cesarean section (cephalopelvic disproportion (0.54;0.36–0.80), dystocia or failure to progress (0.54;0.41–0.70), failed induction (0.56;0.37–0.85), and fetal malpresentation (1.66;1.38–2.01)). Adjusted ORs were similar.

Conclusions

Diabetes, HDCP, Bishop score, labor induction, macrosomia, age, obesity, previous vaginal birth, and the indications for the previous CS should be considered as the factors affecting the success of VBAC.

Term Elective Cesarean Delivery and Offspring Infectious Morbidity: A Population-Based Cohort Study

BACKGROUND

Studies have found associations between delivery mode and offspring long-term health. We aimed to study the possible association between delivery mode and the risk for long-term infectious diseases of the offspring during a follow-up period of up of 18 years.

METHODS

A population-based cohort analysis was performed comparing different subtypes of infectious morbidity leading to hospitalization among children, based on delivery mode (vaginal vs. elective cesarean). Data on pregnancy course and outcome, delivery mode and later offspring hospitalizations were available from a single tertiary center. All singleton uncomplicated deliveries and pregnancies between the years 1991 and 2014 were included in the analysis. Kaplan-Meier and multivariable Weibull survival models were applied to adjust for differences in follow-up time between the study groups and confounders.

RESULTS

During the study period, 138,910 newborns met the inclusion criteria: 13,206 (9.5%) were delivered by elective cesarean delivery, and 125,704 (91.5%) were delivered vaginally. During the follow-up period (median: 10.22 years), 13,054 (9.4%) were hospitalized (at least once) with infectious morbidity: 12.0% and 9.1% among the cesarean and vaginally delivered children, respectively (Relative Risk: 1.36; 95% confidence interval: 1.28-1.43; incidence density rates for first hospitalization were 15.22/1000 person-years and 9.06/1000 person-years among cesarean and vaginally delivered children, respectively; Kaplan-Meier log rank P < 0.001). The association between cesarean delivery and long-term pediatric infectious morbidity remained significant in the multivariable model, controlling for confounding variables (adjusted hazard ratio: 1.18; 95% confidence interval: 1.11-1.25; P < 0.001).

CONCLUSIONS

Children delivered by elective cesarean section are at an increased risk for hospitalization with pediatric infectious morbidity when compared with vaginally delivered children.

The Rates and Medical Necessity of Cesarean Delivery in the Era of the Two-Child Policy in Hubei and Gansu Provinces, China

OBJECTIVES

To describe the cesarean rates in different child policy periods and assess the medical necessity of cesareans during the 2-child policy period.

METHODS

We collected hospital-level aggregate data on 93 745 deliveries and individual-level data on 27 977 deliveries from 6 hospitals in the Hubei and Gansu provinces of China from 2013 to 2016. Experts in gynecology and obstetrics assessed the medical necessity of 1024 randomly selected cesareans in 2016.

RESULTS

The overall cesarean rate decreased significantly from 45.1% in the 1-child policy period (January 2013-September 2014) to 40.4% in the selective 2-child policy period (October 2014-July 2016) and further to 38.9% in the universal 2-child policy period (August 2016-December 2016). The rate of cesarean delivery on maternal request decreased by 46.3%, whereas the rate of cesarean delivery indicated by a previous cesarean delivery increased by 118.8% (P < .001). The experts assessed 222 (21.6%) cesareans as lacking medical necessity.

CONCLUSIONS

The overall cesarean rate in Hubei and Gansu provinces decreased after the implementation of the 2-child policy, and one fifth of cesareans might be nonessential.

Impact of recommended changes in labor management for prevention of the primary cesarean delivery

BACKGROUND

The dramatic rise in cesarean delivery rates worldwide in recent decades, without evidence of a concomitant decrease in cerebral palsy rates, has raised concerns about its potential negative consequences for maternal and infant health. In 2014, the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine jointly published an Obstetric Care Consensus for safe prevention of the primary cesarean delivery.

OBJECTIVE

We sought to assess whether modification of our protocol to implement these recommendations helped to decrease our primary cesarean delivery rate safely.

STUDY DESIGN

This is a before-and-after retrospective cohort study at a university referral hospital. In March 2014, the threshold for defining active labor changed from 4 to >6 cm and arrest of first-stage labor from lack of cervical change despite regular contractions after 3 hours of oxytocin administration with amniotomy and epidural anesthesia to no change after 4 hours of adequate or 6 hours of inadequate contractions in women with an epidural. The definition of second-stage arrest of labor changed simultaneously from lack of progress for 3 hours with adequate contractions in women with epidural anesthesia to no progress for ≥4 hours in nulliparas or 3 hours in multiparas with an epidural. We compared maternal and neonatal outcomes over two 1 year periods: from March 2013 to February 2014 (before, preguideline) and from June 2014 to May 2015 (after, postguideline). We included all women with singleton pregnancies at ≥37 weeks' gestation, in vertex presentation, in spontaneous or induced labor, and with epidural anesthesia. We excluded women with an elective or previous cesarean delivery and those with obstetric or fetal complications.

RESULTS

This study included 3283 and 3068 women in the before and after periods, respectively. The groups had similar general and obstetric characteristics. The global cesarean delivery rate decreased significantly from 9.4% in the preguideline to 6.9% in the postguideline period (odds ratio, 0.71; 95% confidence interval, 0.59-0.85; P < .01). The cesarean delivery rate for arrest of first-stage labor fell by half, from 1.8% to 0.9% (odds ratio, 0.51; 95% confidence interval, 0.31-0.81; P < .01) but was significant only among nulliparous women. The cesarean delivery rate for second-stage arrest of labor decreased but not significantly between periods (1.3% vs 1.0%; odds ratio, 0.73; 95% confidence interval, 0.44-1.22; P = .2), and the cesarean delivery rate for failure of induction remained similar (3.7% vs 3.5%; odds ratio, 1.06; 95% confidence interval, 0.06-13.24; P = .88). The median duration of labor before cesarean delivery also became significantly longer among nulliparous women during the later period. Maternal and neonatal outcomes did not differ between the 2 periods, except that the rate of 1 minute Apgar score <7 fell significantly in the later period (8.4% vs 6.9%; odds ratio, 0.80; 95% confidence interval, 0.66-0.97; P = .02).

CONCLUSION

The modification of our protocol by implementing the new consensus recommendations was associated with a reduction of the rate of primary cesarean delivery performed for arrest of labor with no apparent increase in immediate adverse neonatal outcomes in nulliparous women at term with singleton pregnancies in vertex presentation and with epidural anesthesia. Further studies are needed to assess the long-term maternal and neonatal safety of these policies.

The Maternal Infant Microbiome: Considerations for Labor and Birth

The human microbiome plays a role in maintaining health, but is also thought to attenuate and exacerbate risk factors for adverse maternal-child health outcomes. The development of the microbiome begins in utero; however, factors related to the labor and birth environment have been shown to influence the initial colonization process of the newborn microbiome. This "seeding" or transfer of microbes from the mother to newborn may serve as an early inoculation process with implications for the long-term health outcomes of newborns. Studies have shown that there are distinct differences in the microbiome profiles of newborns born vaginally compared with those born by cesarean. Antibiotic exposure has been shown to alter the microbial profiles of women and may influence the gut microbial profiles of their newborns. Considering that the first major microbial colonization occurs at birth, it is essential that labor and birth nurses be aware of factors that may alter the composition of the microbiome during the labor and birth process. The implications of various activities and factors unique to the labor and birth environment that may influence the microbiome of women and newborns during the labor and birth process (e.g., route of birth, antibiotic use, nursing procedures) are presented with a focus on the role of labor nurses and the potential influence of nursing activities on this process.

Cesarean section without medical indication and risk of childhood asthma, and attenuation by breastfeeding

Background

Previous studies suggest that caesarean section (CS) may increase the risk of asthma in children, but none of them could preclude potential confounding effects of underlying medical indications for CS. We aim to assess the association between CS itself (without medical indications) and risk of childhood asthma.

Methods

We conducted a hospital-based case-control study on childhood asthma with 573 cases and 812 controls in Shanghai. Unconditional logistic regression models in SAS were employed to control for potential confounders.

Results

Our study found that CS without medical indication was significantly associated with elevated asthma risk (adjusted OR = 1.58 [95% CI 1.17–2.13]). However, this risk was attenuated in children fed by exclusive breastfeeding in the first six months after birth (adjusted OR = 1.39 [95% CI 0.92–2.10]). In contrast, the risk was more prominent in children with non-exclusive breastfeeding or bottle feeding (adjusted OR = 1.91 [95% CI 1.22–2.99]).

Conclusions

CS without medical indication was associated with an increased risk of childhood asthma. Exclusive breastfeeding in infancy may attenuate this risk.

Further evidence of psychological factors underlying choice of elective cesarean delivery (ECD) by primigravidae

Objective:

Requests for elective cesarean delivery (ECD) have increased in Iran. While some sociodemographic and fear-related factors have been linked with this choice, psychological factors such as self-esteem, stress, and health beliefs are under-researched.

Methods:

A total of 342 primigravidae (mean age = 25 years) completed questionnaires covering psychological dimensions such as self-esteem, perceived stress, marital relationship quality, perceived social support, and relevant health-related beliefs.

Results:

Of the sample, 214 (62.6%) chose to undergo ECD rather than vaginal delivery (VD). This choice was associated with lower self-esteem, greater perceived stress, belief in higher susceptibility to problematic birth and barriers to an easy birth, along with lower perceived severity of ECD, fewer perceived benefits from VD, lower self-efficacy and a lower feeling of preparedness. No differences were found for marital relationship quality or perceived social support.

Conclusions:

The pattern suggests that various psychological factors such as self-esteem, self-efficacy, and perceived stress underpin the decision by primigravidae to have an ECD.

Maturation of the infant microbiome community structure and function across multiple body sites and in relation to mode of delivery

Human microbial communities are characterized by their taxonomic, metagenomic, and metabolic diversity, which varies by distinct body sites and influences human physiology. However, when and how microbial communities within each body niche acquire unique taxonomical and functional signatures in early life remains underexplored. We thus sought to assess the taxonomic composition and potential metabolic function of the neonatal and early infant microbiota across multiple body sites, and assess the impact of mode of delivery and its potential confounders or modifiers. A cohort of pregnant women in their early 3^rd trimester (n=81) were prospectively enrolled for longitudinal sampling through 6 weeks post-delivery, and a second matched cross-sectional cohort (n=81) was additionally recruited for sampling once at delivery. Samples were collected for each maternal-infant dyad across multiple body sites, including stool, oral gingiva, nares, skin and vagina. 16S rRNA gene sequencing analysis and whole genome shotgun sequencing was performed to interrogate the composition and function of the neonatal and maternal microbiota. We found that the neonatal microbiota and its associated functional pathways were relatively homogenous across all body sites at delivery, with the notable exception of neonatal meconium. However, by 6 weeks, the infant microbiota structure and function had significantly expanded and diversified, with body site serving as the primary determinant of the bacterial community composition and its functional capacity. Although minor variations in the neonatal (immediately at birth) microbiota community structure were associated with Cesarean delivery in some body sites (oral, nares, and skin; R² = 0.038), this was not true in neonatal stool (meconium, Mann-Whitney p>0.05) and there was no observable difference in community function regardless of delivery mode. By 6 weeks of age, the infant microbiota structure and function had expanded and diversified with demonstrable body site specificity (p<0.001, R² = 0.189), and no discernable differences in neither community structure nor function by Cesarean delivery were identifiable (p=0.057, R² = 0.007). We conclude that within the first 6 weeks of life, the infant microbiota undergoes significant reorganization that is primarily driven by body site and not by mode of delivery.

The infant gut bacterial microbiota and risk of pediatric asthma and allergic diseases

Among the many areas being revolutionized by the recent introduction of culture-independent microbial identification techniques is investigation of the relationship between close contact with large animals, antibiotics, breast feeding, mode of birth, and other exposures during infancy as related to a reduced risk of asthma and allergic disease. These exposures were originally clustered under the "Hygiene Hypothesis" which has evolved into the "Microbiota Hypothesis". This review begins by summarizing epidemiologic studies suggesting that the common feature of these allergy risk-related exposures is their influence on the founding and early development of a child's gut microbiota. Next, studies using culture-independent techniques are presented showing that children who have experienced the exposures of interest have altered gut microbiota. Finally, selected mouse and human studies are presented which begin to corroborate the protective exposures identified in epidemiologic studies by elucidating mechanisms through which microbes can alter immune development and function. These microbially driven immune alterations demonstrate that microbial exposures in many cases could alter the risk of subsequent allergic disease and asthma. Hopefully, a better understanding of how microbes influence allergic disease will lead to safe and effective methods for reducing the prevalence of all forms of allergic disease.