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

Cesarean delivery on child health and development in Japanese nationwide birth cohort

The long-term effects of cesarean delivery (CD) on child health and development remain controversial. This study aimed to investigate these effects using an outcome-wide approach in a Japanese context, where perinatal mortality rates are among the world's lowest. We analyzed data from 2,114 children in a nationwide Japanese birth cohort, linking the 21st Century Longitudinal Survey of Newborns with the Perinatal Research Network database. We examined associations between CD and various health and developmental outcomes up to 9 years of age, including hospitalizations, obesity, and developmental milestones. After adjusting for potential confounders, CD was not significantly associated with most outcomes, including all-cause hospitalization (adjusted risk ratio 1.25, 95% CI 0.997-1.56), obesity at 5.5 and 9 years, and various developmental milestones. Subgroup analyses for multiple births and preterm infants showed some differences in point estimates, but were limited by small sample sizes. CD was not significantly associated with adverse long-term child health or developmental outcomes in this Japanese cohort. These findings provide reassurance regarding CD safety when medically indicated in advanced perinatal care settings. Further research with larger samples and longer follow-up is needed, especially for specific subgroups.

The association between caesarean section delivery and obesity at age 17 years. Evidence from a longitudinal cohort study in the United Kingdom

BACKGROUND

Childhood and adolescent obesity are major, preventable public health concerns. Studies to date are inconclusive regarding an association between caesarean section (CS) delivery and offspring obesity, with fewer studies conducted in late adolescence. This study examined the association between CS delivery, with a specific focus on planned CS, and induction of labour and adolescent body mass index (BMI) and body fat percentage (BF%) at age 17 years.

METHODS

Data on 8,880 mother-child pairs from the United Kingdom Millennium Cohort Study were analysed. The exposures were mode of delivery (normal vaginal delivery (VD) (reference), assisted VD, planned CS and emergency CS) and mode of delivery by induction of labour status. Crude and adjusted binary logistic regression and linear regression models were fitted examining BMI and BF% at age 17 years respectively, adjusting for several potential confounders.

RESULTS

Adolescents born by CS did not have an elevated BMI or BF% compared to those born by normal VD. The fully adjusted results for overweight and obesity in children born by planned CS, compared to VD, were 1.05 (95% CI: 0.86-1.28) and 0.94 (95% CI: 0.72-1.23), respectively. The results were similar for the associations between CS and BF%, and between induction of labour and BMI.

CONCLUSION

Overall, this large longitudinal study did not support an association between CS or induction of labour and overweight, obesity or BF%. It is possible that previously reported associations are due to residual or unmeasured confounding and/or underlying indications for CS delivery.

Pre-labor and post-labor cesarean delivery and early childhood adiposity in the Canadian Healthy Infant Longitudinal Development (CHILD) Cohort Study

BACKGROUND/OBJECTIVES

Delivery by cesarean section (CS) compared to vaginal delivery has been associated with increased risk of overweight in childhood. Our study examined if the presence or absence of labor events in CS delivery altered risk of overweight in early childhood (1-5 years) compared to vaginal delivery and if this association differed according to infant sex.

SUBJECTS/METHODS

The study included 3073 mother-infant pairs from the CHILD Cohort Study in Canada. Data from birth records were used to categorize infants as having been vaginally delivered, or delivered by CS, with or without labor events. Age and sex adjusted weight-for-length (WFL) and body mass index (BMI) z scores were calculated from height and weight data from clinic visits at 1, 3 and 5 years and used to classify children as overweight. Associations between delivery mode and child overweight at each timepoint were assessed using regression models, adjusting for relevant confounding factors including maternal pre-pregnancy BMI. Effect modification by infant sex was tested.

RESULTS

One in four infants (24.6%) were born by CS delivery; 13.0% involved labor events and 11.6% did not. Infants born by CS without labor had an increased odds of being overweight at age 1 year compared to vaginally delivered infants after adjustment for maternal pre-pregnancy BMI, maternal diabetes, smoking, infant sex and birthweight-for-gestational age (aOR 1.68 [95% CI 1.05-2.67]). These effects did not persist to 3 or 5 years of age and, after stratification by sex, were only seen in boys (aOR at 1 year 2.21 [95% CI 1.26-3.88]).

CONCLUSION AND RELEVANCE

Our findings add to the body of evidence that CS, in particular CS without labor events, may be a risk factor for overweight in early life, and that this association may be sex-specific. These findings could help to identify children at higher risk for developing obesity.

Caesarean section and childhood obesity at age 3 years derived from the Japan Environment and Children's Study

Caesarean section (CS) birth is widely reported to be a risk factor for childhood obesity. Although susceptibility to childhood obesity is influenced by race and ethnicity, it is unclear whether this risk of childhood obesity with CS birth also applies in the Japanese population. We investigated the impact of CS birth on obesity at 3 years of age in Japanese children. We obtained data from 60,769 mother-toddler pairs in the Japan Environment and Children's Study, a large-scale birth cohort study. Obesity was determined by body mass index measured at 3 years of age. Analysis revealed that 11,241 toddlers (18.5%) had a CS birth and that 4912 toddlers (8.1%) were obese. The adjusted risk ratio for obesity at 3 years of age when born by CS compared with vaginal delivery, estimated using inverse probability of treatment weighting, was 1.16 (95% confidence interval 1.08-1.25). These results suggest that CS birth modestly increases the risk of obesity at 3 years of age in Japanese children.

Caesarean Section Delivery Is Associated with Childhood Overweight and Obesity, Low Childbirth Weight and Postnatal Complications: A Cross-Sectional Study

Background and Objectives: In the last decades, simultaneously increasing trends have been recorded for both caesarean section delivery and childhood overweight/obesity around the world, which are considered serious public health concerns, negatively affecting child health. Aim: The present study aims to investigate whether caesarean section is associated with the increased rates of childhood overweight/obesity, low childbirth anthropometric indices and postnatal complications in pre-school age. Materials and Methods: This is a cross-sectional study in which 5215 pre-school children aged 2–5 years old were enrolled from nine different Greek regions after applying specific inclusion and exclusion criteria. Non-adjusted and adjusted statistical analysis was performed to assess the impact of caesarean section in comparison to vaginal delivery. Results: Children delivered by caesarean section were significantly more frequently overweight or obese at the age of 2–5 years, also presenting a higher prevalence of low birth weight, length and head circumference. Caesarean section was also associated with higher incidence of asthma and diabetes type I at the age of 2–5 years. In a multivariate analysis, caesarean section increased the risk of childhood overweight/obesity and low childbirth anthropometric indices even if adjusting for several childhood and maternal confounding factors. Conclusions: Increasing trends were recorded for both caesarean section delivery and childhood overweight/obesity, which are considered serious public health concerns. Caesarean section independently increased childhood overweight/obesity in pre-school age, highlighting the emergent need to promote health policies and strategies to inform future mothers about its short and long-term risks and that this mode of delivery should preferably be performed only when there are strong medical recommendations in emergency obstetric conditions.

Cesarean birth and risk of obesity from birth to adolescence: A cohort study

BACKGROUND

Recent studies have shown associations between cesarean birth and overweight. However, very few studies have evaluated weight gain or adiposity throughout life, and the majority are restricted to analysis during childhood. The purpose of this study was to analyze the effect of cesarean birth on obesity risk from birth to adolescence.

METHODS

The study sample was drawn from live births that occurred in 1999 and 2000 in Mato Grosso-Brazil. Participants were evaluated once when they were between 0 and 5 years of age and again after approximately 10 years (2009-2011). To measure the association between cesarean birth and obesity (Body Mass Index/age >+2 z-scores), we used generalized estimation equations (GEE) with binomial distribution and log-binomial models for repeated measures, controlled by the following confounding factors: weight and length at birth, sex, gestational age, breastfeeding, maternal age and schooling, economic class in childhood, and maternal smoking during pregnancy. The exposure-time interaction term was evaluated to verify differences in the change in the risk of obesity over time.

RESULTS

56.8% of children in the sample were born by cesarean birth. Children born by cesarean had a higher risk of obesity from birth through adolescence (RR = 1.22, 95% CI = 1.02; 1.46), even after adjusting for covariates, when compared with those born vaginally. However, the time-exposure interaction term was not significant, which indicates that there was no increased risk of obesity over time.

CONCLUSION

Cesarean birth was positively associated with obesity from birth to adolescence, with a persistent risk in the period evaluated.

Crucial nuances in understanding (mis)associations between the neonatal microbiome and Cesarean delivery

As rates of Cesarean delivery and common non-communicable disorders (NCDs), such as obesity, metabolic disease, and atopy/asthma, have concomitantly increased in recent decades, investigators have attempted to discern a causal link. One line of research has led to a hypothesis that Cesarean birth disrupts the presumed normal process of colonization of the neonatal microbiome with vaginal microbes, yielding NCDs later in life. However, a direct link between a disrupted microbiota transfer at time of delivery and acute and/or chronic illness in infants born via Cesarean has not been causally established. Microbiota seeding from maternal vaginal or stool sources has been preliminarily evaluated as an intervention designed to compensate for the lack of (or limited) exposure to such sources among Cesarean-delivered neonates. However, to date, clinical trials have yet to show a clear health benefit with neonatal 'vaginal seeding' practices. Until the long-term effects of these microbiome alterations can be fully determined, it is paramount to conduct parallel meaningful and mechanistic-minded interrogations of the impact of clinically modifiable maternal, nutritional, or environmental exposure on the functional microbiome over the duration of pregnancy and lactation to determine their role in the mitigation of childhood and adult NCDs.

Sex-specific association between elective cesarean section and growth trajectories in preschool children: A prospective birth cohort study

Background

Elective cesarean section (ECS) primarily contributes to the rising cesarean section (CS) rate, and much attention has been attracted to its health consequences. The association between ECS and overweight and obesity in children has been controversial, and few studies distinguished ECS with medical indications from those without indications. Based on a large sample birth cohort, we aim to examine the association of ECS with or without medical indications on children's physical development by using repeated anthropometric data from birth to 6 years of age.

Methods

A total of 2304 mother-child pairs with complete data on delivery mode and children's anthropometric measurements were recruited from the Ma'anshan-Anhui Birth Cohort (MABC) in China. ECS was the main exposure in this study, and the primary outcomes were children's growth trajectories and early adiposity rebound (AR). Children's BMI trajectories were fitted by using group-based trajectory models and fractional polynomial mixed-effects models. The association between ECS and children's growth trajectories and early AR was performed using multiple logistic regression models.

Results

Among 2,304 mother-child pairs (1199 boys and 1105 girls), 1088 (47.2%) children were born by CS, including 61 (5.6%) emergency CS, 441 (40.5%) ECS with medical indications, and 586 (53.9%) ECS without medical indications. After adjusting for potential confounders, it was found that ECS with medical indications was associated with a "high level" of BMI trajectory (OR = 1.776; 95% CI: 1.010-3.123), and ECS without medical indications was associated with early AR (OR = 1.517; 95% CI: 1.123-2.050) in girls. In boys, we found that ECS without medical indications was unlikely to experience an accelerated growth trajectory (OR = 0.484; 95%CI: 0.244-0.959).

Conclusions

ECS may be related to girls' "high level" BMI trajectories and early AR. If causal, the findings will provide an evidence-based reference for early life interventions for childhood obesity.

Relationship between caesarean section delivery and risk of overweight/obesity among children aged 6–23 months in the Tamale Metropolis of Ghana

The recent exponential increase in caesarean section (CS) rates in many countries including Ghana requires an understanding of the potential long-term consequences on child health. The present study investigated the relationship between CS delivery and risk of childhood overweight/obesity. A retrospective cohort study was conducted from October 2019 to March 2020 in Ghana. Using multi-stage sampling, 553 mother–child pairs aged 6–23 months were selected from ten health facilities during child welfare clinic (CWC) services. We assessed the association between delivery mode (caesarean v. vaginal) and subsequent body mass index for age (BMI/age Z-score) using hierarchical multivariable linear regression analysis. The prevalence of overweight/obesity (BMI/age Z-score > +2 sd) in children was 3⋅6 %. After adjusting for maternal gestational weight gain, macrosomia and child feeding practices, children who were born through CS had mean BAZ which was 0⋅105 standard units significantly higher than their colleagues who were delivered through normal vaginal [beta coefficient (β) 0⋅105, (95 % CI 0⋅03, 0⋅55)]. CS birth was also associated with 3⋅2 times higher odds of overweight/obesity than vaginal delivery (AOR 3⋅23; 95 % CI 1⋅14, 9⋅13). Consequently, CS delivery was associated positively with increased body mass (adiposity) in the study sample. The association between CS delivery and risk of childhood obesity was attenuated after adjusting for macrosomia. These results would be important for informing clinicians and expectant mothers in considering CS delivery.

Association of Cesarean Delivery with Trajectories of Growth and Body Composition in Preschool Children

This study aimed to examine the association of cesarean delivery with trajectories of growth and body composition in preschool children. This ambidirectional cohort study was conducted between 2017 and 2020 in China. Information on the delivery mode, weight, and length/height of the children measured at routine healthcare visits was obtained from maternal and child health records. For three years while in kindergarten, children’s body mass index (BMI), fat mass index (FMI), fat-free mass index (FFMI), and percentage of body fat (FM%) were repeatedly measured. A BMI z score (zBMI) was calculated and standardized to WHO measures, and overweight and obesity were defined using the WHO reference. After adjustment for maternal age, maternal education, annual family income, prepregnancy BMI, gestational weight gain, gravidity, parity, gestational age, child sex, birthweight, breastfeeding duration, and the parent-reported dietary intake of the children, children born via cesarean delivery (n = 1992) versus those born vaginally (n = 1578) had higher zBMI growth rates beyond 36 months (β: 0.003; 95% CI: 0.001, 0.005 SD units/month) and elevated levels of FMI (β: 0.097; 95% CI: 0.026, 0.168 kg/m²), FM% (β: 0.402; 95% CI: 0.058, 0.745%) and zBMI (β: 0.073; 95% CI: 0.012, 0.133 units), but not FFMI (β: 0.022; 95% CI: −0.022, 0.066 kg/m²). The adjusted OR of overweight and obesity was 1.21 (95% CI: 1.04, 1.40). Cesarean delivery likely elevated zBMI growth rates and increased the risk of overweight and obesity in preschool children, with the elevation of fat mass but not fat-free mass.

Cesarean section and body mass index in children: is there a causal effect?

Obesity is considered a global public health problem. Cesarean section has been associated with high body mass index (BMI) and increased obesity throughout life. However, this association has been challenged by some studies. This study aims to assess the causal effect of cesarean section on the BMI of children aged 1-3 years. This is a cohort study of 2,181 children aged 1-3 years, born in 2010, obtained from the BRISA Birth Cohort, in São Luís, state of Maranhão, Brazil. Sociodemographic variables, maternal characteristics, type of childbirth, morbidity, anthropometric measurements, and BMI were assessed. Marginal structural models with a counterfactual approach were used to check the causal effect of the type of childbirth on obesity, weighted by the inverse probability of selection and exposure. Out of the 2,181 children assessed (52% female), 50.6% were born by cesarean section, 5.9% of the newborn infants were large for gestational age, and 10.7% of them had excess weight. No causal effect of cesarean section on BMI was observed (coefficient = -0.004; 95%CI: -0.136; 0.127; p = 0.948). Cesarean section did not have a causal effect on the BMI of children aged 1-3 years.

Maternal and early life exposures and their potential to influence development of the microbiome

At the dawn of the twentieth century, the medical care of mothers and children was largely relegated to family members and informally trained birth attendants. As the industrial era progressed, early and key public health observations among women and children linked the persistence of adverse health outcomes to poverty and poor nutrition. In the time hence, numerous studies connecting genetics ("nature") to public health and epidemiologic data on the role of the environment ("nurture") have yielded insights into the importance of early life exposures in relation to the occurrence of common diseases, such as diabetes, allergic and atopic disease, cardiovascular disease, and obesity. As a result of these parallel efforts in science, medicine, and public health, the developing brain, immune system, and metabolic physiology are now recognized as being particularly vulnerable to poor nutrition and stressful environments from the start of pregnancy to 3 years of age. In particular, compelling evidence arising from a diverse array of studies across mammalian lineages suggest that modifications to our metagenome and/or microbiome occur following certain environmental exposures during pregnancy and lactation, which in turn render risk of childhood and adult diseases. In this review, we will consider the evidence suggesting that development of the offspring microbiome may be vulnerable to maternal exposures, including an analysis of the data regarding the presence or absence of a low-biomass intrauterine microbiome.

The association of cesarean section with overweight and neurodevelopment of Chinese children aged 1-5 months

OBJECTIVE

The purpose of this survey was to explore the association of delivery mode with overweight and neurodevelopment of Chinese infants aged 1-5 months.

MATERIALS AND METHODS

This study was based on a cross-sectional survey. Data for this study were obtained from the Children's Nutrition and Health System Survey in China which was conducted from 2019 to 2020. Characteristics of parents and children and the delivery mode were obtained using interview-administered questionnaires. Body mass index-for age z-score (BMI z) was calculated using World Health Organization (WHO) child growth standards. Children's neurodevelopment was assessed by a trained child health care physician using the Child Psychological Development Scale. The association of delivery mode with infant overweight was analyzed using a multivariable logistic regression model. We conducted a multivariable linear regression model to explore the relationship between delivery modes with neurodevelopment.

RESULTS

In total, the present analysis included 1,347 children aged 1-5 months, 35.61% were born via cesarean section, of which 15.21% were overweight. After adjustment for infant characteristics and parental factors, the cesarean section was significantly related with the likehood of being overweight [OR = 1.95; 95% confidence interval (CI): 1.27 to 2.98]. Children born via cesarean section had a 3.41-point decrease in gross motor development (β = -3.41; 95% CI: -5.77 to -1.05), a 3.65-point decrease in fine motor development (β = -3.65; 95% CI: -6.03 to -1.28), and a 2.96-point in language development (β = -2.96; 95% CI: -5.20 to -0.73), a 1.65-point in total development (β = -1.65; 95% CI: -3.17 to -0.14) compared with those who were vaginal birth.

CONCLUSION

In our study population, cesarean section was associated with overweight and neurodevelopment outcomes. The cesarean section might increase the likehood of infant overweight, and might decrease the developmental scores of gross motor, fine motor and language. Further studies should be conducted to verify the associations and explore the possible mechanisms.

Associations of caesarean section with body mass and waist circumference trajectories from age 2 to 13 years: A nationally representative birth cohort study in Australia

BACKGROUND

Measuring obesity at a single time point does not explain the independent association between C-section birth and obesity in a child's life course.

OBJECTIVES

This study aimed to explore the longitudinal link between C-section with obesity trajectories during childhood.

METHODS

We analysed data from a nationally representative birth cohort study named "Longitudinal Study of Australian Children (LSAC)", commenced in 2004. General obesity was measured through the Body Mass Index (BMI) and abdominal obesity by the Waist Circumference (WC) using the biennially collected data from age 2 to 13 years (2006-2016). Group-based trajectory modelling was applied to identify the distinct pattern of BMI & WC trajectories. Multivariable multinomial logistic regression models were used to assess the association between C-section and obesity trajectories after adjusting for perinatal factors.

RESULTS

Of the 3524 study children, 30% were born by C-section. Three distinct BMI trajectory groups emerged: stable normal (60%), moderately rising (33%) and accelerated (7%). The WC trajectories were, stable normal (58%), moderate (34%) and accelerated (8%). Compared with the stable normal group, children born through C-section had a higher risk to follow accelerated trajectories for both BMI (OR:1.72; 95% CI: 1.28-2.32) and WC (OR: 1.51; 95% CI: 1.15-1.98) with P-value <0.01. Adjustment of potential confounders did not alter these associations substantially.

CONCLUSIONS

C-section birth significantly increases the risk of having an accelerated obesity trajectory in children. Limiting the C-section for absolute clinical causes and early institution of preventive approach can reduce the obesity burden among children delivered through C-section.

Caesarean delivery is associated with increased blood pressure in young adult offspring

We examined the associations between caesarean section (CS) delivery and cardiovascular risk factors in young adults in Thailand. Participants were 632 offspring from a birth cohort in Chiang Mai (Northern Thailand), born in 1989–1990 and assessed in 2010 at a mean age of 20.6 years, including 57 individuals (9.0%) born by CS and 575 born vaginally. Clinical assessments included anthropometry, blood pressure (BP), carotid intima-media thickness, and fasting blood glucose, insulin, and lipid profile. Young adults born by CS had systolic BP (SBP) 6.2 mmHg higher (p < 0.001), diastolic BP 3.2 mmHg higher (p = 0.029), and mean arterial pressure (MAP) 4.1 mmHg higher (p = 0.003) than those born vaginally. After covariate adjustments, SBP and MAP remained 4.1 mmHg (p = 0.006) and 2.9 mmHg (p = 0.021) higher, respectively, in the CS group. The prevalence of abnormal SBP (i.e., pre-hypertension or hypertension) in the CS group was 2.5 times that of those born vaginally (25.0% vs 10.3%; p = 0.003), with an adjusted relative risk of abnormal SBP 1.9 times higher (95% CI 1.15, 2.98; p = 0.011). There were no differences in anthropometry (including obesity risk) or other metabolic parameters. In this birth cohort in Thailand, CS delivery was associated with increased blood pressure in young adulthood.

The impact of cesarean delivery on infant DNA methylation

BACKGROUND

Mounting evidence suggests that cesarean delivery may have a long-lasting effect on infant health. But the underlying mechanisms remain unclear. This study aims to examine whether cesarean delivery on maternal request without any medical indications (CDMR) impacts DNA methylation status in the umbilical cord blood of the infant.

METHODS

A cross-sectional study was conducted in Shanghai, China. A total of 70 CDMR and 70 vaginal deliveries (VD) were recruited in 2012. The cord blood DNA methylation status was measured in 30 CDMR and 30 VD newborns using Illumina Infinium Human Methylation 450 K BeadChip. To validate the results, the cord blood DNA methylation status was measured in another 40 CDMR and 40 VD newborns using targeted bisulfite sequencing assay. A total of 497 CpG sites from 40 genes were included in the analysis.

RESULTS

A total of 165 differentially methylated positions (DMPs) exhibited differences in DNA methylation by 10% or more between the CDMR and VD groups, many of which were related to the development of the immune system. Based on the targeted bisulfite sequencing assay, 16 genes (16/22, 72.7%) had higher methylation level in the CDMR group than the VD group. Among them, 5 genes were related to the immune system. After considering the estimation of cell type proportions, there was few significant differences in DNA methylation between CDMR and VD groups.

CONCLUSIONS

The DMPs identified between CDMR and VD groups might be largely explained by the cell type proportions. Further studies are needed to examine DNA methylation in each cell type separately.

Impact of the factors shaping gut microbiota on obesity

Obesity is considered as a risk factor for chronic health diseases such as heart diseases, cancer and diabetes 2. Reduced physical activities, lifestyle, poor nutritional diet and genetics are among the risk factors associated with the development of obesity. In recent years, several studies have explored the link between the gut microbiome and the progression of diseases including obesity, with the shift in microbiome abundance and composition being the main focus. The alteration of gut microbiome composition affects both nutrients metabolism and specific gene expressions, thereby disturbing body physiology. Specifically, the abundance of fibre-metabolizing microbes is associated with weight loss and that of protein and fat-metabolizing bacteria with weight gain. Various internal and external factors such as genetics, maternal obesity, mode of delivery, breastfeeding, nutrition, antibiotic use and the chemical compounds present in the environment are known to interfere with the richness of the gut microbiota (GM), thus influencing weight gain/loss and ultimately the development of obesity. However, the effectiveness of each factor in potentiating the shift in microbes' abundance to result in significant changes that can lead to obesity is not yet clear. In this review, we will highlight the factors involved in shaping GM, their influence on obesity and possible interventions. Understanding the influence of these factors on the diversity of the GM and how to improve their effectiveness on disease conditions could be keys in the treatment of metabolic diseases.

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.

Association of Cesarean Birth with Body Mass Index Trajectories in Adolescence

Background: This study aimed to identify patterns of body mass index (BMI) changes in adolescence and to assess whether delivery mode (Cesarean and vaginal delivery) was associated with BMI trajectories. Methods: This study was conducted among 569 adolescents aged 10–15 years that resided in the city of Zibo, China. The height and weight of each participant were repeatedly measured at 10, 11, 12, 13, 14 and 15 years. Group based trajectory modeling (GBTM) was used to estimate BMI change trajectories, and multinomial logistic regression was conducted to evaluate the independent association of delivery mode and BMI trajectory classes. Results: Of the 569 participants, 407 (71.5%) were vaginal deliveries and 162 (28.5%) were Cesarean deliveries. Five distinct long-term BMI trajectories were identified: “persistent healthy weight” (57.5%), “persistent underweight” (6.5%), “obesity to healthy weight” (7.8%), “progressive overweight” (10.6%), “progressive obesity” (17.6%). Adjusted multinomial logistic models revealed a twofold increase in risks between ages 10–15 years of “progressive obesity” trajectory (OR = 2.50, 95% CI: 1.42, 4.41) for children born through Cesarean section compared with vaginal birth. Conclusions: Five distinct long-term BMI trajectories were identified during adolescence in our research, and we confirmed that Cesarean birth was significantly increased the risk of “progressive obesity” trajectory but not the “obesity to healthy weight” trajectory.

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.

The association between caesarean section delivery and later life obesity in 21-24 year olds in an Urban South African birth cohort

BACKGROUND

Obesity is an important public health problem and rates have reached epidemic proportions in many countries. Studies have explored the association between infants delivered by caesarean section and their later life risk of obesity, in many countries outside Africa. As a result of the increasing caesarean section and obesity rates in South Africa, we investigated the association in this country.

METHODS

This was a retrospective analysis of data that were collected from a prospective South African birth cohort (Birth to Twenty Plus), established in 1990. A total of 889 young adults aged 21-24 years were included in the analysis. Poisson regression models were fitted to assess the association between mode of delivery and early adulthood obesity.

RESULTS

Of the 889 young adults, 106 (11.9%) were obese while 72 (8.1%) were delivered by caesarean section; of which 14 (19.4%) were obese. Caesarean section delivery was significantly associated with obesity in young adults after adjusting for potential confounders like young adults' sex and birth weight, mothers' parity, and education (incidence rate ratio 1.64, 95% CI 1.01-2.68, p = 0.045).

CONCLUSION

The association of caesarean section with early adulthood obesity should be interpreted with caution because data on certain key confounding factors such as mothers' pre-pregnancy body mass index and gestational diabetes were not available. Further research from Africa, with larger sample sizes and databases with useful linking of maternal and infant data, should be conducted.

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.

Investigating Stress Response during Vaginal Delivery and Elective Cesarean Section through Assessment of Levels of Cortisol, Interleukin 6 (IL-6), Growth Hormone (GH) and Insulin-Like Growth Factor 1 (IGF-1)

Background: How do stress related phenomena during labor differ between vaginal delivery (VD) and elective cesarean section (CS), remains of heightened interest. The purpose of this study is to investigate discrepancies regarding the stress response during VD and CS. Methods: Cortisol, interleukin 6 (IL-6), growth hormone (GH) and insulin-like growth factor 1 (IGF-1) levels from parturients’ peripheral blood were evaluated on three time-points, namely during the first stage of labor (TP1), two hours post labor (TP2) and 48 h post labor (TP3). Levels were also evaluated from the umbilical cord blood. A total of 50 women were enrolled in this prospective cohort study, with 24 and 26 subjected to CS and VD, respectively. Results: No statistically significant differences were observed between the two groups at TP1. Only GH levels presented the same pattern during the three time-points among both groups. In the umbilical cord blood, the CS group presented statistically significant higher IGF-1 and GH levels. In the umbilical cord blood, IGF-1 and GH levels were positively correlated, while GH and cortisol levels were negatively correlated. Conclusion: CS is a less stressful procedure than VD and is further associated with less intense inflammation, albeit with a longer inflammatory response period. Labor physiology during CS differs considerably regarding respective observations during VD. This merits extensive investigation in order to decipher these data for optimal clinical practice and guidelines.