Association between caesarean section and childhood obesity: a systematic review and meta-analysis

A good start in life is important-perinatal factors dictate early microbiota development and longer term maturation

Maternal health status is vital for the development of the offspring of humans, including physiological health and psychological functions. The complex and diverse microbial ecosystem residing within humans contributes critically to these intergenerational impacts. Perinatal factors, including maternal nutrition, antibiotic use and maternal stress, alter the maternal gut microbiota during pregnancy, which can be transmitted to the offspring. In addition, gestational age at birth and mode of delivery are indicated frequently to modulate the acquisition and development of gut microbiota in early life. The early-life gut microbiota engages in a range of host biological processes, particularly immunity, cognitive neurodevelopment and metabolism. The perturbed early-life gut microbiota increases the risk for disease in early and later life, highlighting the importance of understanding relationships of perinatal factors with early-life microbial composition and functions. In this review, we present an overview of the crucial perinatal factors and summarise updated knowledge of early-life microbiota, as well as how the perinatal factors shape gut microbiota in short and long terms. We further discuss the clinical consequences of perturbations of early-life gut microbiota and potential therapeutic interventions with probiotics/live biotherapeutics.

The Pediatric Obesity Microbiome and Metabolism Study (POMMS): Methods, Baseline Data, and Early Insights

OBJECTIVE

The purpose of this study was to establish a biorepository of clinical, metabolomic, and microbiome samples from adolescents with obesity as they undergo lifestyle modification.

METHODS

A total of 223 adolescents aged 10 to 18 years with BMI ≥95th percentile were enrolled, along with 71 healthy weight participants. Clinical data, fasting serum, and fecal samples were collected at repeated intervals over 6 months. Herein, the study design, data collection methods, and interim analysis-including targeted serum metabolite measurements and fecal 16S ribosomal RNA gene amplicon sequencing among adolescents with obesity (n = 27) and healthy weight controls (n = 27)-are presented.

RESULTS

Adolescents with obesity have higher serum alanine aminotransferase, C-reactive protein, and glycated hemoglobin, and they have lower high-density lipoprotein cholesterol when compared with healthy weight controls. Metabolomics revealed differences in branched-chain amino acid-related metabolites. Also observed was a differential abundance of specific microbial taxa and lower species diversity among adolescents with obesity when compared with the healthy weight group.

CONCLUSIONS

The Pediatric Metabolism and Microbiome Study (POMMS) biorepository is available as a shared resource. Early findings suggest evidence of a metabolic signature of obesity unique to adolescents, along with confirmation of previously reported findings that describe metabolic and microbiome markers of obesity.

Obesity, Early Life Gut Microbiota, and Antibiotics

Obesity is a major public health problem that continues to be one of the leading risk factors for premature death. Early life is a critical period of time when the gut microbiota and host metabolism are developing in tandem and significantly contribute to long-term health outcomes. Dysbiosis of the gut microbiota, particularly in early life, can have detrimental effects on host health and increase the susceptibility of developing obesity later in life. Antibiotics are an essential lifesaving treatment; however, their use in early life may not be without risk. Antibiotics are a leading cause of intestinal dysbiosis, and early life administration is associated with obesity risk. The following review explores the relevant literature that simultaneously examines antibiotic-induced dysbiosis and obesity risk. Current evidence suggests that disruptions to the composition and maturation of the gut microbiota caused by antibiotic use in early life are a key mechanism linking the association between antibiotics and obesity. Without compromising clinical practice, increased consideration of the long-term adverse effects of antibiotic treatment on host health, particularly when used in early life is warranted. Novel adjunct interventions should be investigated (e.g., prebiotics) to help mitigate metabolic risk when antibiotic treatment is clinically necessary.

Crosstalk between sIgA-Coated Bacteria in Infant Gut and Early-Life Health

Gut microbiota transmission from mother to offspring has attracted much interest in recent years. The gut microbiota in the infant plays a potentially significant role in modulating and maintaining the development of infant immunity. Secretory immunoglobulin A (sIgA), the major immunoglobulin in the intestine, can target polysaccharides and flagellin on the bacterial surface, resulting in sIgA-coated bacteria. The presentation of specific bacteria coated with sIgA may be a signal of disease and provide novel insights into the relationship between infant microbiota and disease. Here, we review the composition of sIgA-coated bacteria in the adult intestine, human milk, and the infant intestine, as well as the factors that influence the development of gut microbiota in early life. Then, we highlight the diseases that are related to variations in sIgA-coated bacteria in the infant and adult intestine. Furthermore, we discuss the possibility that sIgA-coated bacteria could play a role in mediating both innate and adaptive immune responses. Finally, we propose directions for future research to promote our understanding within this field.

A Multimodal Intervention for Prevention of Overweight and Obesity in Schoolchildren. A Protocol Study "PREVIENE-CÁDIZ"

This paper describes the protocol for a study designed to address the high prevalence (40%) of childhood overweight and obesity in the province of Cádiz, Spain, as a reflection of what is happening worldwide. It is widely known that children who suffer from childhood obesity have a higher risk of developing chronic diseases in adulthood. This causes a decrease in the quality of life and an increase in health spending. In this context, it is necessary to intervene promoting healthy lifestyle habits from an early stage. The objective of this project will be to evaluate the effectiveness of a multimodal intervention (individual, school and family) called "PREVIENE-CÁDIZ" [CADIZ-PREVENT]. The intervention will be focused mainly on diet, physical activity, sedentary lifestyle and sleep, to prevent overweight and obesity in schoolchildren from 8 to 9 years old in the province of Cádiz. It will consist of a 10-session education program carried out in the classroom by the teachers. In addition, children will be assigned two workbooks, one to work on in class and the other at home with parents. A workshop aimed at parents will be included to help teach them how to obtain healthier lifestyle habits. The proposed study will involve a quasi-experimental design with a control group.

Birth by cesarean delivery and central adiposity in adolescents from a birth cohort

The aim of this study was to analyze the association between birth by cesarean section and central adiposity in adolescents in São Luís, Maranhão State, Brazil. This was a cohort study that included 601 participants evaluated at birth and at 18-19 years. At birth we assessed type of delivery, maternal education, family income, maternal marital status, maternal body mass index before pregnancy, prenatal care, maternal smoking habit, gestational age at delivery and intrauterine growth restriction. In the adolescents, we evaluated central adiposity using the dual X-ray energy absorptiometry method. The indicators of central fat used were the trunk-to-total fat mass ratio (T/T), the android-to-gynoid fat mass ratio (A/G), the trunk-to-limb fat mass ratio (T/Lb), and the trunk-to-leg fat mass ratio (T/Lg). A theoretical model for the study of associations was developed using directed acyclic graphs, which allowed selecting the variables that required minimum adjustment for inclusion in the predictive model of exposure to cesarean delivery. The data were analyzed with marginal structural models weighted by the inverse of the probability of selection. A total of 38.6% of the adolescents studied were delivered by cesarean section. There was no significant difference in the central adiposity of adolescents delivered by cesarean section according to the indicators used: T/T ( coefficient = -0.003; 95%CI: -0.013; 0.007), A/G (coefficient = 0.001; 95%CI: -0.015; 0.018); T/Lb (coefficient = -0.016; 95%CI: -0.048; 0.016); T/Lg (coefficient = 0.014; 95%CI: -0.060; 0.030). In conclusion, there was no association between cesarean section delivery and greater central adiposity in the studied adolescents.

Birth by cesarean section and mood disorders among adolescents of a birth cohort study in northern Brazil

The increasing number of cesarean sections worldwide has encouraged research on the long-term effects of this birth type on the offspring's mental health. The objective of this study was to investigate whether there is an association between birth by cesarean section and the development of mood disorders (depression and bipolar disorders) in adolescents. A cohort study was carried out with 1603 adolescents from 18 to 19 years old who participated in the third phase of a birth cohort study in São Luís, MA, in 2016. Information on birth type and weight, prematurity, mother's age and schooling, parity, marital status, and smoking behavior during pregnancy, were collected at birth. The study outcomes were depression, bipolar disorder, and "mood disorder" construct. A Directed Acyclic Graph (DAG) was developed to select the variables for minimal adjustment for confounding and collision bias. Associations were estimated through propensity score weighting using a two-step estimation model, and confounders for cesarean birth were used in the predictive model. There was no significant association in the relationship between birth type and depression (95%CI: -0.037 to 0.017; P=0.47), bipolar disorder (95%CI: -0.019 to 0.045; P=0.43), and mood disorder (95%CI: -0.033 to 0.042; P=0.80) in adolescents of both sexes. Birth by cesarean section was not associated with the development of mood disorders in adolescents.

The views of pregnant women in New Zealand on vaginal seeding: a mixed-methods study

Background

Vaginal seeding is the administration of maternal vaginal bacteria to babies following birth by caesarean section (CS), intended to mimic the microbial exposure that occurs during vaginal birth. Appropriate development of the infant gut microbiome assists early immune development and might help reduce the risk of certain health conditions later in life, such as obesity and asthma. We aimed to explore the views of pregnant women on this practice.

Methods

We conducted a sequential mixed-methods study on the views of pregnant women in New Zealand (NZ) on vaginal seeding. Phase one: brief semi-structured interviews with pregnant women participating in a clinical trial of vaginal seeding (n = 15); and phase two: online questionnaire of pregnant women throughout NZ (not in the trial) (n = 264). Reflexive thematic analysis was applied to interview and open-ended questionnaire data. Closed-ended questionnaire responses were analysed using descriptive statistics.

Results

Six themes were produced through analysis of the open-ended data: “seeding replicates a natural process”, “microbiome is in the media”, “seeding may have potential benefits”, “seeking validation by a maternity caregiver”, “seeding could help reduce CS guilt”, and “the unknowns of seeding”. The idea that vaginal seeding replicates a natural process was suggested by some as an explanation to help overcome any initial negative perceptions of it. Many considered vaginal seeding to have potential benefit for the gut microbiome, while comparatively fewer considered it to be potentially beneficial for specific conditions such as obesity. Just under 30% of questionnaire respondents (n = 78; 29.5%) had prior knowledge of vaginal seeding, while most (n = 133; 82.6%) had an initially positive or neutral reaction to it. Few respondents changed their initial views on the practice after reading provided evidence-based information (n = 60; 22.7%), but of those who did, most became more positive (n = 51; 86.4%).

Conclusions

Given its apparent acceptability, and if shown to be safe and effective for the prevention of early childhood obesity, vaginal seeding could be a non-stigmatising approach to prevention of this condition among children born by CS. Our findings also highlight the importance of lead maternity carers in NZ remaining current in their knowledge of vaginal seeding research.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-020-03500-y.

Birth signalling hormones and the developmental consequences of caesarean delivery

Rates of delivery by caesarean section (CS) are increasing around the globe and, although several epidemiological associations have already been observed between CS and health outcomes in later life, more are sure to be discovered as this practice continues to gain popularity. The components of vaginal delivery that protect offspring from the negative consequences of CS delivery in later life are currently unknown, although much attention to date has focused on differences in microbial colonisation. Here, we present the case that differing hormonal experiences at birth may also contribute to the neurodevelopmental consequences of CS delivery. Levels of each of the 'birth signalling hormones' (oxytocin, arginine vasopressin, epinephrine, norepinephrine and the glucocorticoids) are lower following CS compared to vaginal delivery, and there is substantial evidence for each that manipulations in early life results in long-term neurodevelopmental consequences. We draw from the research traditions of neuroendocrinology and developmental psychobiology to suggest that the perinatal period is a sensitive period, during which hormones achieve organisational effects. Furthermore, there is much to be learned from research on developmental programming by early-life stress that may inform research on CS, as a result of shared neuroendocrine mechanisms at work. We compare and contrast the effects of early-life stress with those of CS delivery and propose new avenues of research based on the links between the two bodies of literature. The research conducted to date suggests that the differences in hormone signalling seen in CS neonates may produce long-term neurodevelopmental consequences.

Delivery mode and altered infant growth at 1 year of life in India

BACKGROUND

Cesarean section (C-section) delivered infants are more likely to be colonized by opportunistic pathogens, resulting in altered growth. We examined whether C-section (elective/emergency) vs vaginal delivery was associated with altered weight and linear growth at 1 year of life.

METHODS

A total of 638 mother-infant pairs were included from MAASTHI cohort 2016-2019. Information on delivery mode was obtained from medical records. Based on WHO child growth standards, body mass index-forage z-score (BMI z) and length-for-age z-score (length z) were derived. We ran multivariable linear and Poisson regression models before and after multiple imputation.

RESULTS

The rate of C-section was 43.4% (26.5%: emergency, 16.9%: elective). Percentage of infant overweight was 14.9%. Compared to vaginal delivery, elective C-section was associated with β = 0.57 (95% CI 0.20, 0.95) higher BMI z. Also infants born by elective C-section had RR = 2.44 (95% CI 1.35, 4.41) higher risk of being overweight; no such association was found for emergency C-section. Also, elective C-section delivery was associated with reduced linear growth at 1 year after multiple imputation (β = -0.38, 95% CI -0.76, -0.01).

CONCLUSIONS

Elective C-section delivery might contribute to excess weight and also possibly reduced linear growth at 1 year of age in children from low- and middle-income countries.

IMPACT

Our study, in a low-income setting, suggests that elective, but not emergency, C-section is associated with excess infant BMI z at 1 year of age and elective C (C-section) was also associated with altered linear growth but only in multiple imputation analyses. Elective C-section was associated with a higher risk of being overweight at 1 year of age. Our results indicate that decreasing medically unnecessary elective C-section deliveries may help limit excess weight gain and stunted linear growth among infants.

Effect of Elective Cesarean Section on Children's Obesity From Birth to Adolescence: A Systematic Review and Meta-Analysis

BACKGROUND

Elective cesarean section (ECS) is the most common reason for the increasing cesarean section rate worldwide, and it is reported to be related to adverse short-term and long-term outcomes in both mothers and infants. Findings on the association between ECS and overweight and obesity in children are controversial in recent studies. Therefore, we conducted a systematic review and meta-analysis to examine the effect of ECS on offspring's overweight and obesity.

METHODS

PubMed, Science Direct, Web of Science, CNKI (China National Knowledge Infrastructure), Wanfang Database (in Chinese), and China Biology Medicine disc databases were searched using different combinations of three groups of keywords: "elective cesarean section," "overweight/obesity," and "children." Nine cohort studies and 11 independent risk estimates were finally identified.

RESULTS

We have observed significant association between ECS and children's obesity, the total pooled risk ratio (RR) being 1.10 (95% CI: 1.01-1.18; I ² = 32.4%). In subgroup analysis, ECS was found to be associated with the occurrence of obesity in preschoolers (RR = 1.12, 95% CI: 1.02-1.22; I ² = 16.8%). Furthermore, it revealed that ECS was related with the high risk of children's obesity where the rate of ECS exceeded 10%. No significant association was observed between ECS and children's overweight, and the RR was 1.12 (95% CI: 0.94-1.30; I ² = 55.6%).

CONCLUSIONS

Overall, it indicated that children born via ECS had an increased risk of later-life obesity. Given the global increase in childhood obesity, our findings would provide evidence-based reference for early life intervention on children's obesity.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021267211, identifier: CRD42021267211.

The human virome: assembly, composition and host interactions

The human body hosts vast microbial communities, termed the microbiome. Less well known is the fact that the human body also hosts vast numbers of different viruses, collectively termed the 'virome'. Viruses are believed to be the most abundant and diverse biological entities on our planet, with an estimated 10³¹ particles on Earth. The human virome is similarly vast and complex, consisting of approximately 10¹³ particles per human individual, with great heterogeneity. In recent years, studies of the human virome using metagenomic sequencing and other methods have clarified aspects of human virome diversity at different body sites, the relationships to disease states and mechanisms of establishment of the human virome during early life. Despite increasing focus, it remains the case that the majority of sequence data in a typical virome study remain unidentified, highlighting the extent of unexplored viral 'dark matter'. Nevertheless, it is now clear that viral community states can be associated with adverse outcomes for the human host, whereas other states are characteristic of health. In this Review, we provide an overview of research on the human virome and highlight outstanding recent studies that explore the assembly, composition and dynamics of the human virome as well as host-virome interactions in health and disease.

Effect of maternal asthma exacerbations on perinatal outcomes: a population-based study

Background

Although there is a growing body of literature about the impact of asthma exacerbations during pregnancy on adverse perinatal outcomes, it is still unclear whether asthma exacerbations themselves or asthma severity are the driving factor for negative outcomes. This study aimed to estimate the associations between maternal asthma exacerbations and perinatal outcomes, and whether this differed by asthma treatment regime as a proxy for severity.

Methods

We included births of women with asthma in Sweden from July 2006 to November 2013 (n=33 829). Asthma exacerbations were defined as unplanned emergency visits/hospitalisations or a short course of oral corticosteroids. Adjusted odds ratios (aOR) were estimated for the associations between exacerbations during pregnancy and perinatal outcomes (small for gestational age (SGA), preterm birth, birthweight and mode of delivery), stratified by preconception treatment regime.

Results

Exacerbations occurred in 1430 (4.2%) pregnancies. Exacerbations were associated with reduced birthweight (aOR 1.45, 95% CI 1.24–1.70), and elective (aOR 1.50, 95% CI 1.25–1.79) and emergency caesarean section (aOR 1.35, 95% CI 1.13–1.61). Multiple exacerbations were associated with a 2.6-fold increased odds of SGA (95% CI 1.38–4.82). Amongst women treated prepregnancy with combination therapy (proxy for moderate–severe asthma), exacerbators were at increased odds of elective (aOR 1.69, 95% CI 1.30–2.2) and emergency (aOR 1.62, 95% CI 1.26–2.08) caesarean section, and SGA (aOR 1.74, 95% CI 1.18–2.57) versus non-exacerbators.

Conclusion

Maternal asthma exacerbations increase the risk of SGA and caesarean sections, particularly in women with multiple exacerbations or moderate–severe asthma. Adequate antenatal asthma care is needed to reduce exacerbations and reduce risks of poor outcomes.

Maternal asthma exacerbations are associated with lower birthweight and increased caesarean sections, particularly in women with moderate–severe asthma. Adequate antenatal asthma care is needed to reduce exacerbations and reduce risks of poor outcomes.https://bit.ly/3kF4x8N

Perinatal environment shapes microbiota colonization and infant growth: impact on host response and intestinal function

BACKGROUND

Early microbial colonization triggers processes that result in intestinal maturation and immune priming. Perinatal factors, especially those associated with birth, including both mode and place of delivery are critical to shaping the infant gut microbiota with potential health consequences.

METHODS

Gut microbiota profile of 180 healthy infants (n = 23 born at home and n = 157 born in hospital, 41.7% via cesarean section [CS]) was analyzed by 16S rRNA gene sequencing at birth, 7 days, and 1 month of life. Breastfeeding habits and infant clinical data, including length, weight, and antibiotic exposure, were collected up to 18 months of life. Long-term personalized in vitro models of the intestinal epithelium and innate immune system were used to assess the link between gut microbiota composition, intestinal function, and immune response.

RESULTS

Microbiota profiles were shaped by the place and mode of delivery, and they had a distinct biological impact on the immune response and intestinal function in epithelial/immune cell models. Bacteroidetes and Bifidobacterium genus were decreased in C-section infants, who showed higher z-scores BMI and W/L during the first 18 months of life. Intestinal simulated epithelium had a stronger epithelial barrier function and intestinal maturation, alongside a higher immunological response (TLR4 route activation and pro-inflammatory cytokine release), when exposed to home-birth fecal supernatants, compared with CS. Distinct host response could be associated with different microbiota profiles.

CONCLUSIONS

Mode and place of birth influence the neonatal gut microbiota, likely shaping its interplay with the host through the maturation of the intestinal epithelium, regulation of the intestinal epithelial barrier, and control of the innate immune system during early life, which can affect the phenotypic responses linked to metabolic processes in infants.

TRIAL REGISTRATION

NCT03552939 . Video Abstract.

Mode of delivery, type of labor, and measures of adiposity from childhood to teenage: Project Viva

Background:

Cesarean delivery has been linked with childhood obesity. Few studies have examined if this association is attenuated if there is labor prior to delivery. The objective of this current analysis was to examine the association of cesarean vs. vaginal delivery with measures of childhood adiposity, and whether the association differs by labor type (spontaneous, induced, or absent) preceding cesarean delivery.

Methods:

We ascertained delivery mode and type of labor from medical records in 1443 mother-child dyads from Project Viva with adiposity measures from at least 1 follow-up visit (3369 total observations) in early childhood (median age 3.2y), mid-childhood (median 7.7y), or early teen (median 12.9y). Child adiposity outcomes were CDC age- and sex-specific body mass index (BMI) z-scores, sum of subscapular and triceps skinfold thicknesses (SS+TR; mm), and waist circumference (cm). We used linear regression models with generalized estimating equation estimates adjusted for maternal age, education, race/ethnicity, pre-pregnancy BMI, rate of gestational weight gain, and child sex and age at outcome.

Results:

A total of 333 (23%) women delivered via cesarean, including 155 (11%) with spontaneous labor, 74 (5%) with induced labor, 99 (7%) with no labor, and 5 (<1%) with unknown labor status. Compared to vaginal-delivered children, cesarean-delivered children had higher BMI-z (0.15, 95% CI: 0.04, 0.26); and non-significantly higher waist circumference (0.50 cm, 95% CI: −0.34, 1.34) and SS+TR (0.47 mm, 95% CI: −0.52, 1.46). Cesarean deliveries that were preceded by spontaneous labor were not associated with childhood BMI-z (0.08, 95% CI: −0.07, 0.23), waist circumference (−0.12 cm, 95% CI: −1.09, 0.85), or SS+TR (−0.25 mm, 95% CI: −1.44, 0.93), as compared to vaginal deliveries.

Conclusion:

Cesarean delivery was associated with higher childhood BMI-z, and although waist circumference and SS+TR trended in the same direction, these associations were not significant. Cesarean delivery preceded by spontaneous labor was not associated with adiposity outcomes.

Association of Body Mass Index with Fecal Microbial Diversity and Metabolites in the Northern Finland Birth Cohort

BACKGROUND

Obesity is an established risk factor for multiple cancer types. Lower microbial richness has been linked to obesity, but human studies are inconsistent, and associations of early-life body mass index (BMI) with the fecal microbiome and metabolome are unknown.

METHODS

We characterized the fecal microbiome (n = 563) and metabolome (n = 340) in the Northern Finland Birth Cohort 1966 using 16S rRNA gene sequencing and untargeted metabolomics. We estimated associations of adult BMI and BMI history with microbial features and metabolites using linear regression and Spearman correlations (rs ) and computed correlations between bacterial sequence variants and metabolites overall and by BMI category.

RESULTS

Microbial richness, including the number of sequence variants (rs = -0.21, P < 0.0001), decreased with increasing adult BMI but was not independently associated with BMI history. Adult BMI was associated with 56 metabolites but no bacterial genera. Significant correlations were observed between microbes in 5 bacterial phyla, including 18 bacterial genera, and metabolites in 49 of the 62 metabolic pathways evaluated. The genera with the strongest correlations with relative metabolite levels (positively and negatively) were Blautia, Oscillospira, and Ruminococcus in the Firmicutes phylum, but associations varied by adult BMI category.

CONCLUSIONS

BMI is strongly related to fecal metabolite levels, and numerous associations between fecal microbial features and metabolite levels underscore the dynamic role of the gut microbiota in metabolism.

IMPACT

Characterizing the associations between the fecal microbiome, the fecal metabolome, and BMI, both recent and early-life exposures, provides critical background information for future research on cancer prevention and etiology.

Change in modifiable maternal characteristics and behaviours between consecutive pregnancies and offspring adiposity: A systematic review

Causal evidence links modifiable maternal exposures during the periconceptional period with offspring obesity. The interconception period may be an important time to intervene. We systematically identified studies examining change in modifiable maternal exposures between pregnancies and offspring adiposity. We searched for longitudinal studies published between 1990 and 2019, which included measurements taken on at least two occasions in the period from 1 year prior to the conception of the first birth to the time of the second birth, and which included a measure of adiposity in second, or higher order, siblings. Age, ethnicity and genetics were not considered modifiable; all other factors including length of the interpregnancy interval were. Eleven studies satisfied the inclusion criteria. Higher interpregnancy weight gain or loss, maternal smoking inception, mothers smoking in their first pregnancy and quitting, increasing the number of cigarettes smoked and longer interpregnancy intervals were positively associated with adiposity in second or higher order children. Vaginal birth after caesarean delivery was protective. Further research is needed to ascertain whether the risk of adiposity is fixed based on first pregnancy exposures or if interpregnancy change alters the risk for a subsequent child. This can inform the type and effectiveness of interventions for mothers prior to a subsequent pregnancy.

The association between birth by cesarean section and adolescent cardiorespiratory fitness in a cohort of 339,451 Swedish males

Birth by cesarean section is increasing worldwide and associates with offspring morbidities capable of adversely impacting cardiorespiratory fitness later in life. Whether birth by cesarean section associates with lower levels of cardiorespiratory fitness later in life is unknown and is of interest to public health. Four Swedish national registers were linked to follow 339,451 singleton males, born between 1973–1987 until December 31 2005, for Watt-maximum achieved on a cycle ergometer test at conscription into the Swedish military. Main exposure was birth by cesarean section which was compared to vaginal birth. A sub-population of 45,999 males born between 1982–1987 was identified to explore differentiated associations between elective and non-elective cesarean section with Watt-maximum. Within-family analyses of 34,252 families with 70,632 biological male siblings, who conscripted during the study period, were performed to explore the role of familial confounding on Watt-maximum. Swedish males born by cesarean section achieved lower mean Watt-maximum (− 2.32 W, 95%C.I. − 2.90 to − 1.75) and displayed excess odds of low cardiorespiratory fitness (aOR = 1.08, 95%C.I. 1.05 to 1.11) at conscription in the eighteenth life-year compared to males born vaginally after adjusting for birth characteristics, maternal morbidities and parental socioeconomic position. In the sub-population, males born 1982–1987, there was a greater negative association of elective cesarean section with cardiorespiratory fitness (− 4.42 W, 95%C.I. − 6.27 to − 2.57, p < 0.001) than non-elective cesarean sections (− 1.96 W, 95%C.I. − 3.77 to − 0.16, p = 0.033) as compared to vaginal births. No associations between modes of cesarean delivery and cardiorespiratory fitness levels persisted in the within-family analyses where biological male siblings were compared whilst controlling for factors shared within families. Males born by cesarean section had lower levels of cardiorespiratory fitness eighteen years later compared to males born vaginally. These findings appear to be largely explained by factors of familial confounding.

Differences in maternal gene expression in Cesarean section delivery compared with vaginal delivery

Cesarean section (CS) is recognized as being a shared environmental risk factor associated with chronic immune disease. A study of maternal gene expression changes between different delivery modes can add to our understanding of how CS contributes to disease patterns later in life. We evaluated the association of delivery mode with postpartum gene expression using a cross-sectional study of 324 mothers who delivered full-term (≥ 37 weeks) singletons. Of these, 181 mothers had a vaginal delivery and 143 had a CS delivery (60 with and 83 without labor). Antimicrobial peptides (AMP) were upregulated in vaginal delivery compared to CS with or without labor. Peptidase inhibitor 3 (PI3), a gene in the antimicrobial peptide pathway and known to be involved in antimicrobial and anti-inflammatory activities, showed a twofold increase in vaginal delivery compared to CS with or without labor (adjusted p-value 1.57 × 10^–11 and 3.70 × 10^–13, respectively). This study evaluates differences in gene expression by delivery mode and provides evidence of antimicrobial peptide upregulation in vaginal delivery compared to CS with or without labor. Further exploration is needed to determine if AMP upregulation provides protection against CS-associated diseases later in life.

Caesarean delivery increases the risk of overweight or obesity in 2-year-old children

The aim of this prospective cohort study was to reveal the effect of mode of delivery, independently of other confounders, on the risk of overweight or obesity in infants (age-sex-specific body mass index ≥ 85th percentile). In total, 294 infants born in the Rize Province between November 1 2013, and September 30 2014, and their mothers were included; all infants attended well-child visits with the same family physician for up to two years. Multivariate logistic regression analysis was performed to determine significant associations. The odds ratio (OR) of overweight and obese children aged 2 years in association with the mode of delivery was estimated by logistic regression analysis. In crude analysis, compared with vaginal delivery, the use of Caesarean Section delivery was associated with the risk of childhood overweight or obesity [OR: 2.06; 95% confidence interval (CI): 1.08-4.30]. Even after multivariate adjustment, this increased risk persisted (adjusted OR: 1.93; 95% CI: 1.13-4.18). In conclusion, significantly increased risk of overweight or obesity was found in 2-year-old children born via Caesarean delivery.Impact statementWhat is already known on this subject? Although there are studies on the relationship between childhood obesity and Caesarean Section delivery, results are inconsistent.What do the results of this study add? This is the first prospective cohort study showing the effect of Caesarean delivery on childhood obesity in Turkish children.What are the implications of these findings from clinical practice and/or further research? Future studies should further investigate the exact reasons underlying the association between Caesarean delivery and childhood metabolic syndrome.

The influence of the gastrointestinal microbiome on infant colic

INTRODUCTION

Although infantile colic is relatively frequent, its pathophysiology is not yet understood. The aim of this paper is to provide a better understanding of the link between infantile colic and the gastrointestinal microbiome.

AREAS COVERED

The gastro-intestinal microbiome may already start to develop in the womb and grows exponentially immediately after birth. Factors influencing the microbiome can cause dysbiosis and precipitate symptoms of colic through several mechanisms such as increased gas production and low grade gut inflammation. Other possible factors are immaturity of the enterohepatic bile acid cycle and administration of antibiotics and other medications during the perinatal period. An effective treatment for all colicky infants has yet to be discovered, but the probiotic Lactobacillus reuteri DSM17938 was shown to be effective in breastfed infants with colic. The scientific databases 'Pubmed' and 'Google scholar' were searched from inception until 02/2020. Relevant articles were selected based on the abstract.

EXPERT OPINION

Recent literature confirmed that the composition of the gastrointestinal microbiome is associated with the development of infantile colic. It can be speculated that full sequencing and bioinformatics analysis to identify the microbiome down to the species level may provide answers to the etiology and management of infantile colic.

Association between cesarean delivery types and obesity in preadolescence

Background/Objectives:

The association between mode of delivery and childhood obesity remains inconclusive. Because few studies have separated C-section types (planned or unplanned C-section), our objective was to assess how these subtypes relate to pre-adolescent obesity.

Subjects/Methods:

The study consisted of 570 maternal-child pairs drawn from the WHEALS birth cohort based in Detroit, Michigan. Children were followed-up at 10 years of age where a variety of anthropometric measurements were collected. Obesity was defined based on BMI percentile (≥95th percentile), as well as through gaussian finite mixture modeling on the anthropometric measurements. Risk ratios (RRs) and 95% confidence intervals (CIs) for obesity comparing planned and unplanned C-sections to vaginal deliveries were computed, which utilized inverse probability weights to account for loss to follow-up and multiple imputation for covariate missingness. Mediation models were fit to examine the mediation role of breastfeeding.

Results:

After adjusting for marital status, maternal race, prenatal tobacco smoke exposure, maternal age, maternal BMI, any hypertensive disorders during pregnancy, gestational diabetes, prenatal antibiotic use, child sex, parity, and birthweight z-score, children born via planned C-section had 1.77 times higher risk of obesity (≥95th percentile), relative to those delivered vaginally ((95% CI)=(1.16,2.72); p=0.009). No association was found comparing unplanned C-section to vaginal delivery (RR (95% CI)=0.75 (0.45, 1.23); p=0.25). Results were similar but slightly stronger when obesity was defined by anthropometric class (RR (95% CI)=2.78 (1.47, 5.26); p=0.002). Breastfeeding did not mediate the association between mode of delivery and obesity.

Conclusions:

These findings indicate that children delivered via planned C-section—but not unplanned C-section—have a higher risk of pre-adolescent obesity, suggesting that partial labor or membrane rupture (typically experienced during unplanned C-section delivery) may offer protection. Additional research is needed to understand the biological mechanisms behind this effect, including whether microbiological differences fully or partially account for the association.

Assessment of Variation in Cesarean Delivery Rates Between Public and Private Health Facilities in India From 2005 to 2016

IMPORTANCE

The rates of cesarean deliveries have more than doubled in India, from 8% of deliveries in 2005 to 17% of deliveries in 2016. The World Health Organization recommends that cesarean deliveries should not exceed 10% to 15% of all deliveries in any country. An understanding of the association of private and public facilities with the increase in cesarean delivery rates in India is needed.

OBJECTIVE

To assess the association of public vs private sector health care facilities with cesarean delivery rates in India and to estimate the potential cost savings if private sector facilities followed World Health Organization recommendation for cesarean deliveries.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study used institutional delivery data from the representative National Family Health Survey (NFHS) in India, including data from the NFHS-1 (1992-1993), the NFHS-3 (2005-2006), and the NFHS-4 (2015-2016). The NFHS-3 and NFHS-4 provided data on 22 647 deliveries and 195 366 deliveries, respectively. The NHFS-4 was the first survey to provide data on out-of-pocket expenditures for delivery by facility type, allowing for a comparison of cesarean deliveries and costs between public and private facilities. The primary sample comprised all pregnant women who delivered infants in public and private institutional facilities in India and who were included the NFHS-3 and the NFHS-4; data on pregnant women who were included in the NFHS-1 were used for comparison. The study's findings were analyzed through geographic mapping, data tabulation, funnel plots, multivariate logistic regression analyses, and potential cost-savings scenario analyses. Data were analyzed from June to December 2019.

MAIN OUTCOMES AND MEASURES

The main outcome was the rate of cesarean deliveries by facility type (public vs private) and by participant socioeconomic, demographic, and health characteristics. Secondary outcomes were the potential number of avoidable cesarean deliveries and the potential cost savings if private sector facilities followed the World Health Organization recommendations for cesarean deliveries.

RESULTS

In the NFHS-3, 22 610 total births occurred at institutional facilities. Of those, 2178 births (15.2%) were cesarean deliveries in public facilities, and 3200 births (27.9%) were cesarean deliveries in private facilities. Of 195 366 total institutional births in the NFHS-4, 15 165 births (11.9%) were cesarean deliveries in public facilities, and 20 506 births (40.9%) were cesarean deliveries in private facilities. The cesarean delivery rate in public health facilities increased from 7.2% in the NFHS-1 to 11.9% in the NFHS-4, whereas in private health facilities, the rate increased from 12.3% to 40.9% during the same period. A substantial increase was found in cesarean delivery rates between the NFHS-3 (2005-2006) and the NFHS-4 (2015-2016), with 22 states exceeding the World Health Organization's upper threshold of 15% in the NFHS-4. The odds ratio for cesarean deliveries in private facilities compared with public facilities increased from 1.62 (95% CI, 1.49-1.76) in the NFHS-3 to 4.17 (95% CI, 4.04-4.30) in the NFHS-4. The number of avoidable cesarean deliveries would have been 1.83 million, with a potential cost savings of $320.60 million, if private sector facilities in India had followed the 15% threshold for cesarean delivery rates recommended by the World Health Organization.

CONCLUSIONS AND RELEVANCE

In this study, private sector health facilities were associated with a substantial increase in cesarean deliveries in India. Further research is needed to assess the factors underlying the increase in cesarean deliveries in private sector facilities.

Maternal bacteria to correct abnormal gut microbiota in babies born by C-section

INTRODUCTION

There is evidence that caesarean section (CS) is associated with increased risk of childhood obesity, asthma, and coeliac disease. The gut microbiota of CS-born babies differs to those born vaginally, possibly due to reduced exposure to maternal vaginal bacteria during birth. Vaginal seeding is a currently unproven practice intended to reduce such differences, so that the gut microbiota of CS-born babies is similar to that of babies born vaginally. Our pilot study, which uses oral administration as a novel form of vaginal seeding, will assess the degree of maternal strain transfer and overall efficacy of the procedure for establishing normal gut microbiota development.

METHODS AND ANALYSIS

Protocol for a single-blinded, randomized, placebo-controlled pilot study of a previously untested method of vaginal seeding (oral administration) in 30 CS-born babies. A sample of maternal vaginal bacteria is obtained prior to CS, and mixed with 5 ml sterile water to obtain a supernatant. Healthy babies are randomized at 1:1 to receive active treatment (3 ml supernatant) or placebo (3 ml sterile water). A reference group of 15 non-randomized vaginal-born babies are also being recruited. Babies' stool samples will undergo whole metagenomic shotgun sequencing to identify potential differences in community structure between CS babies receiving active treatment compared to those receiving placebo at age 1 month (primary outcome). Secondary outcomes include differences in overall gut community between CS groups (24 hours, 3 months); similarity of CS-seeded and placebo gut profiles to vaginally-born babies (24 hours, 1 and 3 months); degree of maternal vaginal strain transfer in CS-born babies (24 hours, 1 and 3 months); anthropometry (1 and 3 months) and body composition (3 months).

ETHICS AND DISSEMINATION

Ethics approval by the Northern A Health and Disability Ethics Committee (18/NTA/49). Results will be published in peer-reviewed journals and presented at international conferences.

REGISTRATION

Australian New Zealand Clinical Trials Registry (ACTRN12618000339257).

Rationale and design of "Hearts & Parks": study protocol for a pragmatic randomized clinical trial of an integrated clinic-community intervention to treat pediatric obesity

BACKGROUND

The prevalence of child and adolescent obesity and severe obesity continues to increase despite decades of policy and research aimed at prevention. Obesity strongly predicts cardiovascular and metabolic disease risk; both begin in childhood. Children who receive intensive behavioral interventions can reduce body mass index (BMI) and reverse disease risk. However, delivering these interventions with fidelity at scale remains a challenge. Clinic-community partnerships offer a promising strategy to provide high-quality clinical care and deliver behavioral treatment in local park and recreation settings. The Hearts & Parks study has three broad objectives: (1) evaluate the effectiveness of the clinic-community model for the treatment of child obesity, (2) define microbiome and metabolomic signatures of obesity and response to lifestyle change, and (3) inform the implementation of similar models in clinical systems.

METHODS

Methods are designed for a pragmatic randomized, controlled clinical trial (n = 270) to test the effectiveness of an integrated clinic-community child obesity intervention as compared with usual care. We are powered to detect a difference in body mass index (BMI) between groups at 6 months, with follow up to 12 months. Secondary outcomes include changes in biomarkers for cardiovascular disease, psychosocial risk, and quality of life. Through collection of biospecimens (serum and stool), additional exploratory outcomes include microbiome and metabolomics biomarkers of response to lifestyle modification.

DISCUSSION

We present the study design, enrollment strategy, and intervention details for a randomized clinical trial to measure the effectiveness of a clinic-community child obesity treatment intervention. This study will inform a critical area in child obesity and cardiovascular risk research-defining outcomes, implementation feasibility, and identifying potential molecular mechanisms of treatment response.

CLINICAL TRIAL REGISTRATION

NCT03339440 .

Variation of intrapartum care and cesarean rates among practitioners attending births of low-risk, nulliparous women

BACKGROUND

Variation in hospital cesarean birth rates across the United States is likely because of differences in practitioner practice patterns. Yet, few studies conducted in the last twenty years have examined the relationships between practitioner characteristics and the use of intrapartum interventions and cesarean birth. The objective of this study was to examine associations among practitioner characteristics and the use of amniotomy, epidural, oxytocin augmentation, and cesarean birth in low-risk women with spontaneous onset of labor.

METHODS

A secondary analysis was performed using data collected by the Consortium on Safe Labor. The sample included nulliparous term singleton vertex (NTSV) births with spontaneous onset of labor (n = 13 196) from 2002 to 2007 across eight hospitals. Generalized linear mixed models were conducted to examine outcomes.

RESULTS

The cesarean birth rate ranged from 7.2% to 18.9% across hospitals and from 0% to 53.3% across physicians. Practice type (P < .05) and specialty type (P < .0001) were associated with physician cesarean birth rates. Compared with obstetrician/gynecologists, midwives were nearly twice as likely to use no intrapartum interventions (relative risk 1.80 [CI 95 1.45-2.24]) and 26% less likely to use amniotomy-epidural-oxytocin (0.74 [0.62-0.89]). Family practice physicians had a 21% lower likelihood of using amniotomy-epidural-oxytocin (0.79 [0.67-0.94]) and a 53% lower likelihood of performing cesarean births (0.47 [0.35-0.63]).

CONCLUSIONS

Wide variation in hospital and physician cesarean birth rates was observed in this sample of low-risk, nulliparous women. Practitioner practice type and specialty were significantly associated with the use of intrapartum interventions. Interprofessional practitioner education could be one strategy to reduce variation of intrapartum care and cesarean birth.

Caesarean delivery is associated with higher risk of overweight in the offspring: within-family analysis in the SUN cohort

BACKGROUND

Most studies assessing the association between caesarean delivery (CD) and childhood overweight/obesity have failed to account for important confounders, such as maternal prepregnancy body mass index (BMI) or the indication of the CD. Furthermore, within-family analyses have reported contradictory results. We aimed at evaluating the association between CD and offspring's risk of overweight/obesity while adjusting for important confounders and accounting for correlations between siblings.

METHODS

Women in the 'Seguimiento Universidad de Navarra' cohort provided structured information regarding their pregnancy history and their children's health through online cross-sectional questionnaires. We calculated adjusted differences in BMI z-score and risk ratios (RR) for offspring's overweight/obesity associated with CD, with hierarchical models to account for correlations between siblings. We also performed a within-family analysis in 341 siblings who were discordant in delivery mode, using conditional multivariable logistic regression.

RESULTS

Among the 2791 children analysed, those born by CD had higher average BMI z-scores (difference: 0.17; 95% CI 0.07 to 0.27) and higher risk of overweight/obesity (RR: 1.32, 95% CI 1.05 to 1.65) than children born vaginally. The association did not differ by maternal characteristics or offspring's age strata, and the results were consistent in sensitivity analyses. Furthermore, within-family analysis showed that children born by CD had 2.67-fold higher risk of overweight/obesity (95% CI 1.10 to 5.12) than their peers born vaginally.

CONCLUSION

Children born by CD have higher average BMI z-scores and higher risk of overweight/obesity than children born vaginally. The consistency of these findings across multiple approaches to address potential residual confounding likely suggests a true biological effect.

Caesarean Section Delivery and Risk of Poor Childhood Growth

BACKGROUND

Though emerging evidence indicates caesarean section (CS) brings about late initiation of breastfeeding, early cessation of breastfeeding, and a higher risk of developing obesity, little is documented on the association between CS birth and stunted growth. This study assessed caesarean section delivery and the risk of poor postnatal childhood growth.

METHODS

A retrospective cohort study design was used to collect the requisite data on a sample of 528 mothers having children between the ages of 6 to 24 months. An interviewer-administered questionnaire was used to collect the data.

RESULTS

After controlling for potential confounding factors, linear growth as measured by height-for-age Z-score (HAZ) was significantly higher by 0.121 standard units in children born through normal vaginal delivery, compared to their counterparts born through caesarean section (beta coefficients (β) = 0.121, p=0.002). The mode of delivery also had a statistically significant impact on infant feeding practices. Whereas 70.4% of babies delivered via vagina initiated breastfeeding within one hour of delivery, only 52.7% of babies born through CS did the same. Vaginally delivered babies were 2.1 times more likely to initiate breastfeeding within one hour of delivery ((Crude odds ratio (COR) = 2.13, p < 0.001). Compared to CS babies, vaginally delivered babies were 3.2 times more likely not to have been fed with prelacteal feeds such as water and sugar solutions. Vagina delivered babies were 1.8 times more likely to receive adequate neonatal feeding than their counterparts who were delivered through CS (COR = 1.76, p=0.003).

CONCLUSIONS

This study has found an association between CS delivery and stunting, an adverse outcome that clinicians and patients should weigh when considering in particular elective CS that seeks to avoid the pain associated with a vaginal birth.

Maternal and Perinatal Factors Associated with the Human Milk Microbiome

Microbes are present in human milk regardless of the mother's health. The origins of the milk microbiota likely include the mother's skin, infant's mouth, and transfer from the maternal gastrointestinal (GI) tract. Prominent bacterial taxa in human milk are Staphylococcus and Streptococcus, but many other genera are also found including anaerobic Lactobacillus, Bifidobacterium, and Bacteroides. The milk microbiome is highly variable and potentially influenced by geographic location, delivery mode, time postpartum, feeding mode, social networks, environment, maternal diet, and milk composition. Mastitis alters the milk microbiome, and the intake of Lactobacilli has shown potential for mastitis treatment and prevention. Although milk and infant fecal microbiomes are different, their variations appear to be related - suggesting that milk is an important contributor of early GI colonization. Nonetheless, nothing is known regarding whether the milk microbiome influences infant health. Further research and clinical interventions are needed to determine if changes in the microbiomes of human milk and infant formula/food impact health.

A cross-sectional pilot study of birth mode and vaginal microbiota in reproductive-age women

Recent studies suggest that birth mode (Cesarean section [C-section] or vaginal delivery) is an important event in the initial colonization of the human microbiome and may be associated with long-term health outcomes. We sought to determine the association between a woman's birth mode and her vaginal microbiota in adulthood. We re-contacted 144 adult women from two U.S. studies and administered a brief survey. Vaginal microbiota was characterized on a single sample by amplicon sequencing of the V3-V4 hypervariable regions of the 16S rRNA gene and clustered into community state types (CSTs). We evaluated the association between birth mode and a CST with low relative abundance of Lactobacillus spp. ("molecular bacterial vaginosis" [Molecular-BV]) compared to Lactobacillus-dominated CSTs in logistic regression modeling which adjusted for body mass index, a confounder in this analysis. Twenty-seven women (19%) reported C-section. Overall, C-section showed a non-significant trend towards increased odds of Molecular-BV (aOR = 1.22, 95% CI: 0.45, 3.32), and Prevotella bivia was the strongest single taxa associated with C-section. However, because the two archived studies had different inclusion criteria (interaction p = 0.048), we stratified the analysis by study site. In the study with a larger sample size (n = 88), women born by C-section had 3-fold higher odds of Molecular-BV compared to vaginally-delivered women (aOR = 3.55, p = 0.06, 95% CI: 0.97-13.02). No association was found in the smaller study (n = 56, aOR = 0.19, p = 0.14, 95% CI: 0.02-1.71). This pilot cross-sectional study suggests a possible association between C-section and Molecular-BV in adulthood. However, the analysis is limited by small sample size and lack of comparability in participant age and other characteristics between the study sites. Future longitudinal studies could recruit larger samples of women, address the temporal dynamics of vaginal microbiota, and explore other confounders, including maternal factors, breastfeeding history, and socioeconomic status, which may affect the relationship between birth mode and vaginal microbiota.

Associations between human milk oligosaccharides and growth in infancy and early childhood

BACKGROUND

Breastfeeding modulates infant growth and protects against the development of obesity. However, whether or not maternal variation in human milk components, such as human milk oligosaccharides (HMOs), is associated with programming of child growth remains unknown.

OBJECTIVE

Our objective was to determine the association between maternal HMO composition and child growth during the first 5 y of life. In addition, the association between maternal prepregnancy BMI and HMO composition was assessed.

METHODS

Human milk samples from 802 mothers were obtained from a prospective population-based birth cohort study, Steps to healthy development of Children (STEPS), conducted in Turku, Finland. HMO composition in these milk samples was analyzed by HPLC. Child growth data from 3 mo to 5 y were collected from municipal well-baby clinics and linked to maternal HMO composition data to test for associations.

RESULTS

Maternal HMO composition 3 mo after delivery was associated with height and weight during the first 5 y of life in children of secretor mothers. Specifically, HMO diversity and the concentration of lacto-N-neo-tetraose (LNnT) were inversely associated and that of 2'-fucosyllactose (2'FL) was directly associated with child height and weight z scores in a model adjusted for maternal prepregnancy BMI, mode of delivery, birthweight z score, sex, and time. Maternal prepregnancy BMI was associated with HMO composition.

CONCLUSIONS

The association between maternal HMO composition and childhood growth may imply a causal relation, which warrants additional testing in preclinical and clinical studies, especially since 2'FL and LNnT are among the HMOs now being added to infant formula. Furthermore, altered HMO composition may mediate the impact of maternal prepregnancy BMI on childhood obesity, which warrants further investigation to establish the cause-and-effect relation.

Birth by Caesarean section and otitis media in childhood: a retrospective cohort study

The objective of the present study was to examine the association between birth by Caesarean section (CS) and otitis media (OM) in childhood. We assembled a retrospective cohort of children born between 2003 and 2007 in Nova Scotia and followed them through to 2014. The cohort was derived through a linkage of the Nova Scotia Atlee Perinatal Database with provincial administrative health data. Cox proportional hazards, negative binomial regression and logistic regression were used to examine the association between CS and OM. Among the 36,318 children, 27% were born by CS, and 78% had at least one OM episode (median 2 episodes). Children born by CS were at a slightly higher risk of OM (hazard ratio 1.06, 95% confidence interval (CI) 1.03, 1.09), had more OM episodes in the first 7 years of life (incidence rate ratio 1.04, 95% CI 1.01, 1.07), and were more likely to be above the 95th percentile for OM episodes than children born vaginally (odds ratio 1.10, 95% CI 0.99, 1.23). Our study shows that birth by CS is weakly associated with OM in childhood, but the clinical and public health impact of these findings is small.

The association between breastmilk oligosaccharides and faecal microbiota in healthy breastfed infants at two, six, and twelve weeks of age

Several factors affect gut microbiota development in early life, among which breastfeeding plays a key role. We followed 24 mother-infant pairs to investigate the associations between concentrations of selected human milk oligosaccharides (HMOs) in breastmilk, infant faeces, and the faecal microbiota composition in healthy, breastfed infants at two, six and 12 weeks of age. Lactation duration had a significant effect on breastmilk HMO content, which decreased with time, except for 3-fucosyllactose (3FL) and Lacto-N-fucopentaose III (LNFP III). We confirmed that microbiota composition was strongly influenced by infant age and was associated with mode of delivery and breastmilk LNFP III concentration at two weeks, with infant sex, delivery mode, and concentrations of 3′sialyllactose (3′SL) in milk at six weeks, and infant sex and Lacto-N-hexaose (LNH) in milk at 12 weeks of age. Correlations between levels of individual breastmilk HMOs and relative abundance of OTUs found in infant faeces, including the most predominant Bifidobacterium OTUs, were weak and varied with age. The faecal concentration of HMOs decreased with age and were strongly and negatively correlated with relative abundance of OTUs within genera Bifidobacterium, Parabacteroides, Escherichia-Shigella, Bacteroides, Actinomyces, Veillonella, Lachnospiraceae Incertae Sedis, and Erysipelotrichaceae Incertae Sedis, indicating the likely importance of these taxa for HMO metabolism in vivo.

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 Gut Microbiota and Environmental Factors in Type 1 Diabetes Pathogenesis

Type 1 Diabetes (T1D) is regarded as an autoimmune disease characterized by insulin deficiency resulting from destruction of pancreatic β-cells. The incidence rates of T1D have increased worldwide. Over the past decades, progress has been made in understanding the complexity of the immune response and its role in T1D pathogenesis, however, the trigger of T1D autoimmunity remains unclear. The increasing incidence rates, immigrant studies, and twin studies suggest that environmental factors play an important role and the trigger cannot simply be explained by genetic predisposition. Several research initiatives have identified environmental factors that potentially contribute to the onset of T1D autoimmunity and the progression of disease in children/young adults. More recently, the interplay between gut microbiota and the immune system has been implicated as an important factor in T1D pathogenesis. Although results often vary between studies, broad compositional and diversity patterns have emerged from both longitudinal and cross-sectional human studies. T1D patients have a less diverse gut microbiota, an increased prevalence of Bacteriodetes taxa and an aberrant metabolomic profile compared to healthy controls. In this comprehensive review, we present the data obtained from both animal and human studies focusing on the large longitudinal human studies. These studies are particularly valuable in elucidating the environmental factors that lead to aberrant gut microbiota composition and potentially contribute to T1D. We also discuss how environmental factors, such as birth mode, diet, and antibiotic use modulate gut microbiota and how this potentially contributes to T1D. In the final section, we focus on existing recent literature on microbiota-produced metabolites, proteins, and gut virome function as potential protectants or triggers of T1D onset. Overall, current results indicate that higher levels of diversity along with the presence of beneficial microbes and the resulting microbial-produced metabolites can act as protectors against T1D onset. However, the specifics of the interplay between host and microbes are yet to be discovered.

Early-life determinants of excess weight in children born heavy

Infants born heavy are vulnerable to later obesity, but it is unknown whether obesity-related risk factors present between conception and delivery predict their postnatal weight trajectory. We modelled the weight trajectories of infants born high birth weight (HBW, greater than or equal to 4000 g) and/or large for gestational age (LGA, greater than 90th percentile) using data from the Infant Feeding Practices Study II (N = 371). A high percentage of infants were both HBW and LGA, but the trajectories were modelled separately. Weight of infants born heavy begins high, gradually decreases, and then levels off by 12 months. Delivery method was the only predictor of weight. Caesarean-delivered HBW infants were heavier than vaginally-delivered HBW infants although this effect disappeared by 12 months. Findings indicate that early-life influences are not necessarily deterministic of the postnatal weight trajectory of infants born heavy. Future research is needed to examine postnatal behaviours that may be implicated in the relationship between large size at birth and later obesity.

Prenatal and Peripartum Exposure to Antibiotics and Cesarean Section Delivery Are Associated with Differences in Diversity and Composition of the Infant Meconium Microbiome

The meconium microbiome may provide insight into intrauterine and peripartum exposures and the very earliest intestinal pioneering microbes. Prenatal antibiotics have been associated with later obesity in children, which is thought to be driven by microbiome dependent mechanisms. However, there is little data regarding associations of prenatal or peripartum antibiotic exposure, with or without cesarean section (CS), with the features of the meconium microbiome. In this study, 16S ribosomal RNA gene sequencing was performed on bacterial DNA of meconium samples from 105 infants in a birth cohort study. After multivariable adjustment, delivery mode (p = 0.044), prenatal antibiotic use (p = 0.005) and peripartum antibiotic use (p < 0.001) were associated with beta diversity of the infant meconium microbiome. CS (vs. vaginal delivery) and peripartum antibiotics were also associated with greater alpha diversity of the meconium microbiome (Shannon and Simpson, p < 0.05). Meconium from infants born by CS (vs. vaginal delivery) had lower relative abundance of the genus Escherichia (p < 0.001). Prenatal antibiotic use and peripartum antibiotic use (both in the overall analytic sample and when restricting to vaginally delivered infants) were associated with differential abundance of several bacterial taxa in the meconium. Bacterial taxa in the meconium microbiome were also differentially associated with infant excess weight at 12 months of age, however, sample size was limited for this comparison. In conclusion, prenatal and peripartum antibiotic use along with CS delivery were associated with differences in the diversity and composition of the meconium microbiome. Whether or not these differences in the meconium microbiome portend risk for long-term health outcomes warrants further exploration.

Elective and nonelective cesarean section and obesity among young adult male offspring: A Swedish population-based cohort study

BACKGROUND

Previous studies have suggested that cesarean section (CS) is associated with offspring overweight and obesity. However, few studies have been able to differentiate between elective and nonelective CS, which may differ in their maternal risk profile and biological pathway. Therefore, we aimed to examine the association between differentiated forms of delivery with CS and risk of obesity in young adulthood.

METHODS AND FINDINGS

Using Swedish population registers, a cohort of 97,291 males born between 1982 and 1987 were followed from birth until conscription (median 18 years of age) if they conscripted before 2006. At conscription, weight and height were measured and transformed to World Health Organization categories of body mass index (BMI). Maternal and infant data were obtained from the Medical Birth Register. Associations were evaluated using multinomial and linear regressions. Furthermore, a series of sensitivity analyses were conducted, including fixed-effects regressions to account for confounders shared between full brothers. The mothers of the conscripts were on average 28.5 (standard deviation 4.9) years old at delivery and had a prepregnancy BMI of 21.9 (standard deviation 3.0), and 41.5% of the conscripts had at least one parent with university-level education. Out of the 97,291 conscripts we observed, 4.9% were obese (BMI ≥ 30) at conscription. The prevalence of obesity varied slightly between vaginal delivery, elective CS, and nonelective CS (4.9%, 5.5%, and 5.6%, respectively), whereas BMI seemed to be consistent across modes of delivery. We found no evidence of an association between nonelective or elective CS and young adulthood obesity (relative risk ratio 0.96, confidence interval 95% 0.83-1.10, p = 0.532 and relative risk ratio 1.02, confidence interval 95% 0.88-1.18, p = 0.826, respectively) as compared with vaginal delivery after accounting for prepregnancy maternal BMI, maternal diabetes at delivery, maternal hypertension at delivery, maternal smoking, parity, parental education, maternal age at delivery, gestational age, birth weight standardized according to gestational age, and preeclampsia. We found no evidence of an association between any form of CS and overweight (BMI ≥ 25) as compared with vaginal delivery. Sibling analysis and several sensitivity analyses did not alter our findings. The main limitations of our study were that not all conscripts had available measures of anthropometry and/or important confounders (42% retained) and that our cohort only included a male population.

CONCLUSIONS

We found no evidence of an association between elective or nonelective CS and young adulthood obesity in young male conscripts when accounting for maternal and prenatal factors. This suggests that there is no clinically relevant association between CS and the development of obesity. Further large-scale studies are warranted to examine the association between differentiated forms of CS and obesity in young adult offspring.

TRIAL REGISTRATION

Registered as observational study at ClinicalTrials.gov Identifier: NCT03918044.

Influence of early-life risk factors on socioeconomic inequalities in weight gain

Background

Previous research has examined the role of early-life risk factors on childhood weight gain.The extent to which these factors drive socioeconomic differences in weight is unclear. We aimed to quantify the influence of early-life risk factors on the development of socioeconomic inequalities in children's body mass index (BMI) z-score at 10-11 years.

Methods

Overall, 2186 children from the Longitudinal Study of Australian Children were examined. Socioeconomic position (SEP) was measured as a continuous composite of parent's education, occupation and income. The Product of Coefficients mediation method was used to quantify the contribution of maternal smoking during pregnancy, gestational diabetes, prematurity, caesarean section, birthweight, not being breastfed, early introduction of solid food, maternal BMI and paternal BMI to the relationship between SEP and BMI z-score.

Results

Each increasing decile of SEP (higher SEP) was associated with a 0.05 unit lower (95% CI: -0.06, -0.03) BMI z-score at 10-11 years. In total, 83.5% of these differences in BMI z-score could be explained by socioeconomic differences in maternal smoking during pregnancy (26.9%), maternal BMI (39.6%) and paternal BMI (17.0%).

Conclusions

Interventions to reduce socioeconomic inequalities in excess weight gain during childhood should support the attainment of a healthy parental weight and prevent smoking during pregnancy.

The relationship of prenatal and infant antibiotic exposure with childhood overweight and obesity: a systematic review

This study aimed to assess the evidence regarding the relationship between early-life antibiotic exposure and childhood overweight/obesity by reviewing observational studies on prenatal antibiotic exposure and systematic reviews on infant antibiotic exposure. A search in Pubmed, Embase and Google Scholar covering the period 1st January till 1st December 2018 led to the identification of five studies on prenatal antibiotic exposure and four systematic reviews on infant antibiotic exposure. Positive trends between prenatal antibiotic exposure and overweight/obesity were reported in all studies; two studies reported a significant overall relationship and the other three reported significant relationships under certain conditions. Effect sizes ranged from odds ratio (OR): 1.04 (0.62-1.74) to relative risk (RR): 1.77 (1.25-2.51). Regarding infant antibiotics, one review concluded there was substantial evidence that infant antibiotic exposure increased the risk of childhood overweight/obesity [pooled effect sizes: RR: 1.21 (1.09-1.33) for overweight and RR: 1.18 (1.12-1.25) for obesity]. Two reviews concluded there was some evidence for a relationship [pooled effect sizes: OR: 1.05 (1.00-1.11) and OR: 1.11 (1.02-1.20)]. The fourth review concluded the studies were too heterogeneous for meta-analyses and the evidence regarding the relationship between infant antibiotic exposure and childhood overweight/obesity was inconclusive. More well-designed studies are needed that include data on intra-partum antibiotics and address important potential confounders (including maternal and childhood infections). This review points to some evidence of a relationship between early-life antibiotic exposure and childhood overweight/obesity; this is especially evident in certain children (i.e. exposed to multiple and broad-spectrum antibiotics, earlier postnatal exposure and male gender) and merits further research.

Caesarean section delivery and childhood obesity in a British longitudinal cohort study

Background

Several studies reported an association between Caesarean section (CS) birth and childhood obesity. However, there are several limitations in the current literature. These include an inability to distinguish between planned and emergency CS, small study sample sizes and not adjusting for pre-pregnancy body-mass-index (BMI). We examined the association between CS delivery and childhood obesity using the United Kingdom Millennium Cohort Study (MCS).

Methods

Mother-infant pairs were recruited into the MCS. Use of sampling weights ensured the sample was representative of the population. The exposure was categorised as normal vaginal delivery (VD) [reference], assisted VD, planned CS and emergency CS. Childhood obesity prevalence, at age three, five, seven, eleven and fourteen years was calculated using the International Obesity Taskforce criteria. Mixed-effects linear regression models were fitted with associations adjusted for several potential confounders like maternal age, pre-pregnancy BMI, education and infant macrosomia. Linear regression models were fitted evaluating body fat percentage (BF%), at age seven and fourteen years.

Results

Of the 18,116 infants, 3872 (21.4%) were delivered by CS; 9.2% by planned CS. Obesity prevalence was 5.4%, 5.7%, 6.5%, 7.1% and 7.6% at age three, five, seven, eleven and fourteen years respectively. The mixed-effects linear regression model showed no association between planned (adjusted mean difference = 0.00; [95% confidence interval (CI) -0.10; 0.10], p-value = 0.97) or emergency CS (adjusted mean difference = 0.08; [95% CI -0.01; 0.17], p-value = 0.09) and child BMI. At age seven years, there was no association between planned CS and BF% (adjusted mean difference = 0.13; [95% CI -0.23; 0.49]); there was no association at age fourteen years.

Conclusions

Infants born by planned CS did not have a significantly higher BMI or BF% compared to those born by normal VD. This may suggest that the association, described in the literature, could be due to the indications/reasons for CS birth or residual confounding.

Meconium-stained amniotic fluid as a protective factor against childhood dermatitis and skin rash-related hospitalization in the offspring - a population-based cohort analysis

BACKGROUND

Gut microbiome influences cutaneous diseases including atopic dermatitis. Possible impact of intrauterine exposure to meconium on the occurrence of dermatitis and skin rash was proposed.

OBJECTIVE

We investigated the possible influence of intrauterine exposure to meconium-stained amniotic fluid (MSAF) on the occurrence of dermatitis and skin rash-related hospitalizations throughout childhood.

METHODS

Singleton deliveries occurring between 1991 and 2014 at a single medical centre were divided into two study groups based on presence or lack of MSAF during delivery. Population-based cohort analysis, Kaplan-Meier survival analysis and Cox proportional hazards model were used to study the association between MSAF and cutaneous morbidity-related hospitalizations.

RESULTS

A lower rate of the total dermatitis or skin eruption-related hospitalization was documented in the MSAF-exposed group; 0.78 per 1000-person years (0.9%, n = 312), as compared to 0.98 per 1000-person years in the unexposed group (1.0%, n = 1992) with a hazard ratio of 0.86 (95% CI 0.76-0.96, P = 0.011). The survival curve showed lower cumulative hospitalization rate in the MSAF-exposed group as compared to the unexposed group (log rank P = 0.01). The Cox analysis, controlled for confounders, demonstrated MSAF exposure to be an independent protective factor for dermatitis and skin rash-related hospitalizations during childhood (adjusted HR 0.878 (95% CI 0.779-0.990, P = 0.034).

CONCLUSION

Fetal exposure to MSAF appears to be an independent protective factor for dermatitis and skin rash-related hospitalizations in the offspring throughout childhood and adolescence.

Association of Cesarean Delivery With Risk of Neurodevelopmental and Psychiatric Disorders in the Offspring: A Systematic Review and Meta-analysis

Importance

Birth by cesarean delivery is increasing globally, particularly cesarean deliveries without medical indication. Children born via cesarean delivery may have an increased risk of negative health outcomes, but the evidence for psychiatric disorders is incomplete.

Objective

To evaluate the association between cesarean delivery and risk of neurodevelopmental and psychiatric disorders in the offspring.

Data Sources

Ovid MEDLINE, Embase, Web of Science, and PsycINFO were searched from inception to December 19, 2018. Search terms included all main mental disorders in the Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition).

Study Selection

Two researchers independently selected observational studies that examined the association between cesarean delivery and neurodevelopmental and psychiatric disorders in the offspring.

Data Extraction and Synthesis

Two researchers independently extracted data according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) and Meta-analysis of Observational Studies in Epidemiology (MOOSE) reporting guidelines and assessed study quality using the Newcastle-Ottawa Scale. Random-effects meta-analyses were used to pool odds ratios (ORs) with 95% CIs for each outcome. Sensitivity and influence analyses tested the robustness of the results.

Main Outcomes and Measures

The ORs for the offspring with any neurodevelopmental or psychiatric disorder who were born via cesarean delivery compared with those were born via vaginal delivery.

Results

A total of 6953 articles were identified, of which 61 studies comprising 67 independent samples were included, totaling 20 607 935 deliveries. Compared with offspring born by vaginal delivery, offspring born via cesarean delivery had increased odds of autism spectrum disorders (OR, 1.33; 95% CI, 1.25-1.41; I2 = 69.5%) and attention-deficit/hyperactivity disorder (OR, 1.17; 95% CI, 1.07-1.26; I2 = 79.2%). Estimates were less precise for intellectual disabilities (OR, 1.83; 95% CI, 0.90-3.70; I2 = 88.2%), obsessive-compulsive disorder (OR, 1.49; 95% CI, 0.87-2.56; I2 = 67.3%), tic disorders (OR, 1.31; 95% CI, 0.98-1.76; I2 = 75.6%), and eating disorders (OR, 1.18; 95% CI, 0.96-1.47; I2 = 92.7%). No significant associations were found with depression/affective psychoses or nonaffective psychoses. Estimates were comparable for emergency and elective cesarean delivery. Study quality was high for 82% of the cohort studies and 50% of the case-control studies.

Conclusions and Relevance

The findings suggest that cesarean delivery births are associated with an increased risk of autism spectrum disorder and attention-deficit/hyperactivity disorder, irrespective of cesarean delivery modality, compared with vaginal delivery. Future studies on the mechanisms behind these associations appear to be warranted.

Does cesarean delivery impact infant weight gain and adiposity over the first year of life?

BACKGROUND

Potentially driven by the lack of mother-to-infant transmission of microbiota at birth, cesarean delivery has been associated with higher risk of offspring obesity. Yet, no studies have examined when delivery-mode differences in adiposity begin to emerge. In this study, we examine differences in infant weight and adiposity trajectories from birth to 12 months by delivery mode.

METHODS

From 2013 to 2015, we recruited pregnant women into the Nurture Study and followed up their 666 infants. We ascertained maternal delivery method and infant birth weight from medical records. We measured weight, length, and skinfold thicknesses (subscapular, triceps, abdominal) when infants were 3, 6, 9, and 12 months of age. The main outcome, infant weight-for-length z score, was derived based on the WHO Child Growth Standards. We used linear regression models to assess the difference at each time point and used linear mixed models to examine the growth rate for infant weight and adiposity trajectories. We controlled for maternal age, race, marital status, education level, household income, smoking status, maternal pre-pregnancy body mass index, and infant birth weight.

RESULTS

Of the 563 infants in our final sample, 179 (31.8%) were cesarean delivered. From birth to 12 months, the rate of increase in weight-for-length z score was 0.02/month (p = 0.03) greater for cesarean-delivered than vaginally-delivered infants. As a result of more rapid growth, cesarean-delivered infants had higher weight-for-length z score (0.26, 95% CI: 0.05, 0.47) and sum of subscapular and triceps (SS + TR) skinfold thickness (0.95 mm, 95% CI: 0.30, 1.60)-an indicator for overall adiposity-at 12 months, compared to vaginally-delivered infants.

CONCLUSIONS

Compared to vaginal delivery, cesarean delivery was associated with greater offspring rate of weight gain over the first year and differences in adiposity that appear as early as 3 months of age. Monitoring cesarean-delivered infants closely for excess weight gain may help guide primordial prevention of obesity later in life.

Childhood obesity in New Zealand

BACKGROUND

Paediatric obesity has reached epidemic proportions globally, resulting in significant adverse effects on health and wellbeing. Early life events, including those that happen before, during, and after pregnancy can predispose children to later obesity. The purpose of this review is to examine the magnitude of obesity among New Zealand children and adolescents, and to determine their underlying risk factors and associated comorbidities.

DATA SOURCES

PubMed, Web of Science, and Google Scholar searches were performed using the key terms "obesity", "overweight", "children", "adolescents", and "New Zealand".

RESULTS

Obesity is a major public health concern in New Zealand, with more than 33% of children and adolescents aged 2-14 years being overweight or obese. Obesity disproportionately affects Māori (New Zealand's indigenous population) and Pacific children and adolescents, as well as those of lower socioeconomic status. New Zealand's obesity epidemic is associated with numerous health issues, including cardiometabolic, gastrointestinal, and psychological problems, which also disproportionately affect Māori and Pacific children and adolescents. Notably, a number of factors may be useful to identify those at increased risk (such as demographic and anthropometric characteristics) and inform possible interventions.

CONCLUSIONS

The prevalence of overweight and obese children and adolescents in New Zealand is markedly high, with a greater impact on particular ethnicities and those of lower socioeconomic status. Alleviating the current burden of pediatric obesity should be a key priority for New Zealand, for the benefit of both current and subsequent generations. Future strategies should focus on obesity prevention, particularly starting at a young age and targeting those at greatest risk.

Cesarean Delivery and Hypertension in Early Adulthood

The rate of cesarean delivery (CD) is high in many parts of the world. Birth via CD has been associated with adverse later health outcomes, such as obesity, asthma, and type 1 diabetes mellitus. Few studies have focused on hypertension. We investigated the associations of CD with hypertension, systolic blood pressure (BP), and diastolic BP and tested whether body mass index (BMI; weight (kg)/height (m)2) was a mediator of these associations in a birth cohort (n = 2,020) assembled in 1978-1979 and followed up in 2002-2004 in Ribeirão Preto, Brazil. The CD rate was 32.0%. Hypertension was present in 11.7% of persons born via CD and 7.7% of those born vaginally. Being born by CD increased the odds of hypertension by 51% (odds ratio = 1.51, 95% confidence interval (CI): 1.10, 2.07). After adjustment for confounders, this estimate changed little (odds ratio = 1.49, 95% CI: 1.07, 2.06). In a mediation analysis, odds ratios for the indirect and direct effects were 1.18 (95% CI: 1.11, 1.25) and 1.31 (95% CI: 0.97, 1.65), respectively. CD also had indirect effects on both systolic and diastolic BP via BMI. Our findings suggest that CD is associated with young-adult hypertension and that this association is at least partially mediated by BMI. This has implications for countries struggling with the burden of noncommunicable diseases and where CD rates are high.

Cesarean Delivery and Healthcare Utilization and Costs in the Offspring: A Retrospective Cohort Study

OBJECTIVE

To examine the association between cesarean delivery and healthcare utilization and costs in offspring from birth until age 7 years.

STUDY DESIGN

A retrospective cohort study of singleton term births in the Canadian province of Nova Scotia between 2003 and 2007 followed until age 7 years was conducted using data from the Nova Scotia Atlee Perinatal Database and administrative health data. The main exposure was mode of delivery (cesarean delivery vs vaginal birth); the outcome was healthcare utilization and costs during the first 7 years of life. Associations were modeled using multiple regression adjusting for maternal prepregnancy weight and sociodemographic factors.

RESULTS

In total, 32 464 births were included in the analysis. Compared with children born by vaginal birth, children born by cesarean delivery had more physician visits (incidence rate ratio 1.06, 95% CI 1.05-1.08) and longer hospital stays (incidence rate ratio 1.12, 95% CI 1.03-1.21) and were more likely to be high utilizers of physician visits (OR 1.23, 95% CI 1.10-1.37). Physician and hospital costs were $775 higher for children born by cesarean delivery compared with vaginal birth.

CONCLUSIONS

Cesarean delivery compared with vaginal birth is associated with small but statistically significant increases in healthcare utilization and costs during the first 7 years of life.

Association between caesarean section delivery and obesity in childhood: a longitudinal cohort study in Ireland

OBJECTIVES

To investigate the association between caesarean section (CS) birth and body fat percentage (BF%), body mass index (BMI) and being overweight or obese in early childhood.

DESIGN

Prospective longitudinal cohort study.

SETTING

Babies After Screening for Pregnancy Endpoints: Evaluating the Longitudinal Impact on Neurological and Nutritional Endpoints cohort.

PARTICIPANTS

Infants born to mothers recruited from the Screening for Pregnancy Endpoints study, Cork University Maternity Hospital between November 2007 and February 2011.

OUTCOME MEASURE

Overweight or obese defined according to the International Obesity Task Force criteria.

RESULTS

Of the 1305 infants, 362 (27.8%) were delivered by CS. On regression analysis, BF% at 2 months did not differ significantly by delivery mode. Infants born by CS had a higher mean BMI at 6 months compared with those born vaginally (adjusted mean difference=0.24; 95% CI 0.06 to 0.41, p value=0.009). At 2 years, no difference was seen across the exposure groups in the risk of being overweight or obese. At 5 years, the association between prelabour CS and the risk of overweight or obesity was not statistically significant (adjusted relative risk ratio, aRRR=1.37; 95% CI 0.69 to 2.69) and the association remained statistically nonsignificant when children who were macrosomic at birth were excluded from the model (aRRR=0.86; 95% CI 0.36 to 2.08).

CONCLUSION

At 6 months of age, children born by CS had a significantly higher BMI but this did not persist into future childhood. There was no evidence to support an association between mode of delivery and long-term risk of obesity in the child.

Cesarean birth and the growth of Yucatec Maya and Toba/Qom children

OBJECTIVE

Cesarean delivery is often epidemiologically associated with childhood obesity. However, little attention is paid to post-birth modulatory environments, and most studies are conducted in settings where obesity arises for a number of reasons in addition to birth mode. We therefore assess population differences in the relationship between birth mode and childhood growth using data from rural and peri-urban Latin American indigenous populations, and test predictions developed using life history theory.

METHODS

Child height and weight were measured monthly in 80 Yucatec Maya and 58 Toba/Qom children aged 1-48 months (2007-2014, 3812 observations). Random-effects linear mixed models were used to compare children's growth by population, sex, and birth mode, accounting for potential confounders.

RESULTS

Cesarean delivery rates were 47% (Toba/Qom) and 20% (Yucatec Maya). Childhood obesity and overweight rates were low in both populations. Cesarean-delivered children had significantly greater weight gain (but similar height grain) compared to vaginally-delivered children. By age 4, cesarean delivered Yucatec Maya girls and boys, and Toba/Qom boys (not girls), had significantly higher weight-for-age compared to vaginally-delivered children from their own sex and population.

CONCLUSIONS

This provides one of the first attempts to document differences in children's growth patterns according to mode of birth in modernizing indigenous populations. Cesarean delivery is associated with young children's growth patterns, even in the absence of many obesity-inducing factors. There are also population, age, and sex differences in the relationship between birth mode and childhood weight trajectories that warrant future investigation.