Epigenetic modulation at birth - altered DNA-methylation in white blood cells after Caesarean section

Prenatal maternal stress is associated with site-specific and age acceleration changes in maternal and newborn DNA methylation

Prenatal maternal stress has a negative impact on child health but the mechanisms through which maternal stress affects child health are unclear. Epigenetic variation, such as DNA methylation, is a likely mechanistic candidate as DNA methylation is sensitive to environmental insults and can regulate long-term changes in gene expression. We recruited 155 mother-newborn dyads in the Democratic Republic of Congo to investigate the effects of maternal stress on DNA methylation in mothers and newborns. We used four measures of maternal stress to capture a range of stressful experiences: general trauma, sexual trauma, war trauma, and chronic stress. We identified differentially methylated positions (DMPs) associated with general trauma, sexual trauma, and war trauma in both mothers and newborns. No DMPs were associated with chronic stress. Sexual trauma was positively associated with epigenetic age acceleration across several epigenetic clocks in mothers. General trauma and war trauma were positively associated with newborn epigenetic age acceleration using the extrinsic epigenetic age clock. We tested the top DMPs for enrichment of DNase I hypersensitive sites (DHS) and found no enrichment in mothers. In newborns, top DMPs associated with war trauma were enriched for DHS in embryonic and foetal cell types. Finally, one of the top DMPs associated with war trauma in newborns also predicted birthweight, completing the cycle from maternal stress to DNA methylation to newborn health outcome. Our results indicate that maternal stress is associated with site-specific changes in DNAm and epigenetic age acceleration in both mothers and newborns.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

A predictive model for preterm infants with bronchopulmonary dysplasia based on ferroptosis-related lncRNAs

BACKGROUND

Bronchopulmonary dysplasia (BPD) is the most challenging chronic lung disease for prematurity, with difficulties in early identification. Given lncRNA emerging as a novel biomarker and the regulator of ferroptosis, this study aims to develop a BPD predictive model based on ferroptosis-related lncRNAs (FRLs).

METHODS

Using a rat model, we firstly explored mRNA levels of ferroptosis-related genes and ferrous iron accumulation in BPD rat lungs. Subsequently, a microarray dataset of umbilical cord tissue from 20 preterm infants with BPD and 34 preterm infants without BPD were downloaded from the Gene Expression Omnibus databases. Random forest and LASSO regression were conducted to identify diagnostic FRLs. Nomogram was used to construct a predictive BPD model based on the FRLs. Finally, umbilical cord blood lymphocytes of preterm infants born before 32 weeks gestational age and term infants were collected and determined the expression level of diagnostic FRLs by RT-qPCR.

RESULTS

Increased iron accumulation and several dysregulated ferroptosis-associated genes were found in BPD rat lung tissues, indicating that ferroptosis was participating in the development of BPD. By exploring the microarray dataset of preterm infants with BPD, 6 FRLs, namely LINC00348, POT1-AS1, LINC01103, TTTY8, PACRG-AS1, LINC00691, were determined as diagnostic FRLs for modeling. The area under the receiver operator characteristic curve of the model was 0.932, showing good discrimination of BPD. In accordance with our analysis of microarray dataset, the mRNA levels of FRLs were significantly upregulated in umbilical cord blood lymphocytes from preterm infants who had high risk of BPD.

CONCLUSION

The incorporation of FRLs into a predictive model offers a non-invasive approach to show promise in improving early detection and management of this challenging chronic lung disease in premature infant, enabling timely intervention and personalized treatment strategies.

The Anesthetic Modality but Not the Mode of Delivery Seem to Modulate the Methylation Status of Cyclooxygenase-2 Promoter of the Newborns

OBJECTIVE

Cesarean section (CS) rates are high. Epidemiological data supports increased risk of inflammatory conditions in the offspring born by CS. Epigenetic alterations occurring during the perinatal period may account for this risk. Cyclooxygenase-2 (COX2) has strong implications for inflammatory diseases. The methylation of COX2 of newborn infants was compared with respect to their mode of delivery.

STUDY DESIGN

Ninety healthy term infants born by vaginal delivery (VD), planned cesarean section (PCS), or emergency CS (ECS) were recruited (30 infants in each group). For obstetric anesthesia, local (LA), regional (RA), or general (GA) anesthesia were used. Carefully selected exclusion criteria were implemented to eliminate any confounders with potential epigenetic effects. Umbilical artery blood samples were collected. Demographic and clinical characteristics, folate and CRP levels, and mean methylation levels of the COX2 gene promoter were determined.

RESULTS

Except the birth weight and maternal age parameters, VD, PCS, and ECS were similar. The methylation percentage of COX2 was higher in ECS (16.9 ± 5.1) than VD (14.5 ± 4.1) and PCS (14.8 ± 2.9), albeit p was 0.064. Because of the dual anesthetic modality populations (RA and GA) in PCS and ECS and the recent literature on anesthetics and epigenetics, the anesthetic modality groups were also analyzed. The methylation percentage of COX2 was significantly different between LA, RA, and GA groups (14.5 ± 4.1, 13.9 ± 2.8, and 17.0 ± 4.6, respectively, p = 0.012).

CONCLUSION

When the mode of delivery is the question of debate, the anesthetic modality should be remembered as an important epigenetic modulator.

KEY POINTS

· Perinatal period is a vulnerable time period for epigenetic modulations.. · The mode of delivery is influential in any potential epigenetic alterations occurring perinatally.. · The obstetric anesthetic modality should be remembered as an important epigenetic modulator..

RNA-Sequencing Reveals Gene Expression and Pathway Signatures in Umbilical Cord Blood Affected by Birth Delivery Mode

Cesarean section (CS) confers increased risk of type I diabetes, asthma, inflammatory bowel disease, celiac disease, overweight and obesity, etc., in the offspring. However, the underlying mechanism remains unknown. To investigate the influence of CS on gene expression in cord blood, we have performed RNA-sequencing followed by single-gene analysis, gene set enrichment analysis, gene co-expression network analysis, and interacting genes/proteins analysis in eight full-term infants born by elective CS and eight matched vaginally delivered (VD) infants. Crucial genes identified above were further validated in another 20 CS and 20 VD infants. We found for the first time that mRNA expression of genes involved in immune response (IL12A, INFG, IL1B, TNF, MIF, IL4, CA1, IFI27, HLA-DOB and EPHB1) and metabolism (DLK1, CYP2A6 and GATM) were significantly influenced by CS. Notably, serum TNF-α and IFN-γ were remarkably up-regulated in the CS infants (p = 5.0 × 10-4 and 3.0 × 10-3, respectively) compared to the VD infants. It is biologically plausible that CS may exert adverse impacts on offspring health through influencing expression of genes in the above processes. These findings will help understand the potential underlying mechanisms of the adverse health impacts of CS and identify biomarkers for future health of offspring born with different delivery modes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43657-022-00086-7.

Overweight and Obesity in Adult Birth by Cesarean Section: A Systematic Review With Meta-analysis

CONTEXT

Overweight/obesity is one of the most important health problems. Birth by cesarean section has been shown to influence long-term health outcomes including obesity.

OBJECTIVE

The aim of this systematic review-meta-analysis is to update acknowledgment of the increased risk of cesarean section on offspring's overweight/obesity.

METHODS

This study follows the PRISMA guidelines. A systematic literature search was conducted on Scopus, PubMed, and Web of Science; we have selected all the articles published until January 2, 2022. For inclusion, studies must have reported either (i) both birth by cesarean section and adult (≥18 years) offspring's body mass index; (ii) cohort or case-control study design; and (iii) a risk estimate. Heterogeneity testing was performed using Cochran's Q and I2 statistics. Publication bias was assessed by the Egger test and the Begg test. Meta-analysis was performed through a random-effects model.

RESULTS

Twelve studies with a combined population of 180 065 subjects were included in the meta-analysis. The overall analysis (N = 19) yielded a combined risk estimate for overweight/obesity of 1.19 (95% CI, 1.08-1.30) and the test of heterogeneity resulted into Q = 57.44 ( I2 = 68.67%, P ≤ .001). The risk of offspring obesity is 1.23 (95% CI, 1.09-1.39) and the test of heterogeneity resulted into Q = 39.55 ( I2 = 69.66%, P ≤ .001). Children born by cesarean section have an increased risk of obesity in adulthood.

Estimating the effect of cesarean delivery on long-term childhood health across two countries

Assessing the impact of cesarean delivery (CD) on long-term childhood outcomes is challenging as conducting a randomized controlled trial is rarely feasible and inferring it from observational data may be confounded. Utilizing data from electronic health records of 737,904 births, we defined and emulated a target trial to estimate the effect of CD on predefined long-term pediatric outcomes. Causal effects were estimated using pooled logistic regression and standardized survival curves, leveraging data breadth to account for potential confounders. Diverse sensitivity analyses were performed including replication of results in an external validation set from the UK including 625,044 births. Children born in CD had an increased risk to develop asthma (10-year risk differences (95% CI) 0.64% (0.31, 0.98)), an average treatment effect of 0.10 (0.07-0.12) on body mass index (BMI) z-scores at age 5 years old and 0.92 (0.68-1.14) on the number of respiratory infection events until 5 years of age. A positive 10-year risk difference was also observed for atopy (10-year risk differences (95% CI) 0.74% (-0.06, 1.52)) and allergy 0.47% (-0.32, 1.28)). Increased risk for these outcomes was also observed in the UK cohort. Our findings add to a growing body of evidence on the long-term effects of CD on pediatric morbidity, may assist in the decision to perform CD when not medically indicated and paves the way to future research on the mechanisms underlying these effects and intervention strategies targeting them.

Prenatal vitamin intake in first month of pregnancy and DNA methylation in cord blood and placenta in two prospective cohorts

BACKGROUND

Prenatal vitamin use is recommended before and during pregnancies for normal fetal development. Prenatal vitamins do not have a standard formulation, but many contain calcium, folic acid, iodine, iron, omega-3 fatty acids, zinc, and vitamins A, B6, B12, and D, and usually they contain higher concentrations of folic acid and iron than regular multivitamins in the US Nutrient levels can impact epigenetic factors such as DNA methylation, but relationships between maternal prenatal vitamin use and DNA methylation have been relatively understudied. We examined use of prenatal vitamins in the first month of pregnancy in relation to cord blood and placenta DNA methylation in two prospective pregnancy cohorts: the Early Autism Risk Longitudinal Investigation (EARLI) and Markers of Autism Risk Learning Early Signs (MARBLES) studies.

RESULTS

In placenta, prenatal vitamin intake was marginally associated with -0.52% (95% CI -1.04, 0.01) lower mean array-wide DNA methylation in EARLI, and associated with -0.60% (-1.08, -0.13) lower mean array-wide DNA methylation in MARBLES. There was little consistency in the associations between prenatal vitamin intake and single DNA methylation site effect estimates across cohorts and tissues, with only a few overlapping sites with correlated effect estimates. However, the single DNA methylation sites with p-value < 0.01 (EARLI cord nCpGs = 4068, EARLI placenta nCpGs = 3647, MARBLES cord nCpGs = 4068, MARBLES placenta nCpGs = 9563) were consistently enriched in neuronal developmental pathways.

CONCLUSIONS

Together, our findings suggest that prenatal vitamin intake in the first month of pregnancy may be related to lower placental global DNA methylation and related to DNA methylation in brain-related pathways in both placenta and cord blood.

Is Aberrant DNA Methylation a Key Factor in Molar Incisor Hypomineralization?

Molar incisor hypomineralization (MIH) is a qualitative disturbance of the enamel of the permanent molars and/or incisors. Its etiology is not clearly defined but is connected with different factors occurring before and after birth. It remains difficult to identify a single factor or group of factors, and the problem is further complicated by various overlapping mechanisms. In this study, we attempted to determine whether DNA methylation-an epigenetic mechanism-plays a key role in the etiology of MIH. We collected the epithelium of the oral mucosa from children with MIH and healthy individuals and analyzed its global DNA methylation level in each child using a 5-mC DNA ELISA kit after DNA isolation. There was no statistically significant difference between the global DNA methylation levels in the study and control groups. Then, we also analyzed the associations of the DNA methylation levels with different prenatal, perinatal, and postnatal factors, using appropriate statistical methods. Factors such as number of pregnancies, number of births, type of delivery, varicella infection (under 3 years old), and high fever (under 3 years old) were significantly important. This work can be seen as the first step towards further studies of the epigenetic background of the MIH etiology.

Epigenetic regulation of pediatric and neonatal immune responses

Epigenetic regulation of transcription is a collective term that refers to mechanisms known to regulate gene transcription without changing the underlying DNA sequence. These mechanisms include DNA methylation and histone tail modifications which influence chromatin accessibility, and microRNAs that act through post-transcriptional gene silencing. Epigenetics is known to regulate a variety of biological processes, and the role of epigtenetics in immunity and immune-mediated diseases is becoming increasingly recognized. While DNA methylation is the most widely studied, each of these systems play an important role in the development and maintenance of appropriate immune responses. There is clear evidence that epigenetic mechanisms contribute to developmental stage-specific immune responses in a cell-specific manner. There is also mounting evidence that prenatal exposures alter epigenetic profiles and subsequent immune function in exposed offspring. Early life exposures that are associated with poor long-term health outcomes also appear to impact immune specific epigenetic patterning. Finally, each of these epigenetic mechanisms contribute to the pathogenesis of a wide variety of diseases that manifest during childhood. This review will discuss each of these areas in detail. IMPACT: Epigenetics, including DNA methylation, histone tail modifications, and microRNA expression, dictate immune cell phenotypes. Epigenetics influence immune development and subsequent immune health. Prenatal, perinatal, and postnatal exposures alter immune cell epigenetic profiles and subsequent immune function. Numerous pediatric-onset diseases have an epigenetic component. Several successful strategies for childhood diseases target epigenetic mechanisms.

Placental mtDNA copy number and methylation in association with macrosomia in healthy pregnancy

INTRODUCTION

Fetal growth and development depend on metabolic energy from placental mitochondria. However, the impact of placental mitochondria on the occurrence of macrosomia remains unclear. We aimed to explore the association between macrosomia without gestational diabetes mellitus (non-GDM) and changes in placental mitochondrial DNA (mtDNA) copy number and methylation.

METHODS

Fifty-four newborns with macrosomia and 54 normal birthweight controls were enrolled in this study. Placental mtDNA copy number and mRNA expression of nuclear genes related to mitochondrial replication or ATP synthesis-related genes were measured by real-time quantitative polymerase chain reaction (qPCR). Methylation levels of the non-coding regulatory region D-loop and ATP synthesis-related genes were detected by targeted bisulfite sequencing.

RESULTS

Newborns with macrosomia had lower placental mtDNA copy number and higher methylation rates of the CpG15 site in the D-loop region (D-CpG15) and CpG6 site in the cytochrome C oxidase III (COX3) gene (COX3-CpG6) than normal birth weight newborns. After adjusting for potential covariates (gestational age, prepregnancy BMI, and infant sex), decreased placental mtDNA copy number (adjusted odds ratio [aOR] = 2.09, 95% confidence interval [CI] 1.03-4.25), elevated methylation rate of D-CpG15 (aOR = 2.06, 95% CI 1.03-4.09) and COX3-CpG6 (aOR = 2.13, 95% CI 1.08-4.20) remained significantly associated with a higher risk of macrosomia.

DISCUSSION

Reduced mtDNA copy number and increased methylation levels of specific loci at mtDNA would increase the risk of macrosomia. However, the detailed molecular mechanism needs further identification.

Delivery by caesarean section and offspring adiposity and cardio-metabolic health at ages 6.5, 11.5 and 16 years: results from the PROBIT cohort in Belarus

BACKGROUND

Caesarean delivery has been associated with later adiposity, perhaps via early programming or perhaps because of residual confounding by maternal or birth characteristics.

OBJECTIVES

Examine associations of caesarean delivery with adiposity and cardio-metabolic biomarkers.

METHODS

Observational analysis of 15 069 children in the PROBIT cohort in Belarus. We examined measures of child anthropometry and blood pressure at 6.5, 11.5 and 16 years and fasting blood (11.5 years).

RESULTS

Caesarean-delivered children were slightly heavier at 6.5 (mean BMI 15.8 vs. 15.6 kg/m² ), 11.5 (18.4 vs. 18.2) and 16 years (21.5 vs. 21.3). After adjustment for prenatal characteristics including maternal third trimester BMI, however, we observed no association of caesarean versus vaginal delivery with child BMI (β 0.05 kg/m² ; 95%CI: -0.03, 0.14), sum of skinfolds (0.14 mm; -0.13, 0.42), waist circumference (-0.07 cm; -0.23, 0.10), obesity (OR 0.99; 0.76, 1.29), or systolic (-0.20 mmHg; -0.70, 0.30) or diastolic (-0.17 mmHg, -0.60, 0.26) blood pressure at 6.5 years; results were similar at 11.5 and 16 years. At 11.5 years, we observed a modest association of caesarean delivery with fasting insulin (0.33 mU/L; 0.00, 0.65).

CONCLUSIONS

Caesarean delivery had little or no association with adiposity or related cardio-metabolic biomarkers in childhood. Adjustment for maternal BMI attenuated all outcome effect estimates.

Validation of reference genes for whole blood gene expression analysis in cord blood of preterm and full-term neonates and peripheral blood of healthy adults

Background

Preterm birth is the leading cause of neonatal morbidity and mortality, but research efforts in neonatology are complicated due to the unavailability of large volume blood samples. Whole blood assays can be used to overcome this problem by performing both functional and gene expression studies using small amounts of blood. Gene expression studies using RT-qPCR estimate mRNA-levels of target genes normalized to reference genes. The goal of this study was to identify and validate stable reference genes applicable to cord blood samples obtained from developing neonates of different gestational age groups as well as to adult peripheral blood samples. Eight reference gene candidates (ACTB, B2M, GAPDH, GUSB, HPRT, PPIB, RPLP0, RPL13) were analyzed using the three published software algorithms Bestkeeper, GeNorm and NormFinder.

Results

A normalization factor consisting of ACTB and PPIB allows for comparative expression analyses of neonatal samples from different gestational age groups. Normalization factors consisting of GAPDH and PPIB or ACTB and GAPDH are suitable when samples from preterm and full-term neonates and adults are compared. However, all candidate reference genes except RPLP0 exhibited significant intergroup gene expression variance and a higher gene expression towards an older age which resulted in a small but statistically significant systematic bias. Systematic analysis of RNA-seq data revealed new reference gene candidates with potentially superior stability.

Conclusions

The current study identified suitable normalization factors and proposed the use of the additional single gene RPLP0 to avoid systematic bias. This combination will enable comparative analyses not only between neonates of different gestational ages, but also between neonates and adults, as it facilitates more detailed investigations of developmental gene expression changes. The use of software algorithms did not prevent unintended systematic bias. This generally highlights the need for careful validation of such results to prevent false interpretation of potential age-dependent changes in gene expression. To identify the most stable reference genes in the future, RNA-seq based global approaches are recommended.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07801-0.

Maternal and perinatal factors are associated with risk of pediatric central nervous system tumors and poorer survival after diagnosis

Central nervous system (CNS) tumors are the most common solid tumors in children. Findings on the role of maternal and perinatal factors on the susceptibility or outcome of these tumors are inconclusive. Therefore, we investigated the association between these early-life factors, risk, and survival of pediatric CNS tumors, using data from one of the world’s largest and most diverse cancer registries. Information on pediatric CNS tumor cases (n = 1950) for the period 1995–2011 was obtained from the Texas Cancer Registry. Birth certificate controls were frequency-matched on birth year at a ratio of 10:1 for the same period. Evaluated maternal and perinatal variables were obtained from birth records. Unconditional logistic regression was used to generate adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for etiological factors. Additionally, Cox proportional hazards regression was employed to assess adjusted hazard ratios (HRs) and 95% CIs for survival factors. The results indicated that Hispanic and non-Hispanic black mothers were less likely to have children with CNS tumors compared to non-Hispanic white mothers (OR 0.88 [95% CI 0.78–0.98] P-value = 0.019; OR 0.79 [95% CI 0.67–0.93 P-value = 0.004], respectively). Infants born large for gestational age (OR 1.26 [95% CI 1.07–1.47] P-value = 0.004) and those delivered pre-term (OR 1.19 [95% CI 1.04–1.38] P-value = 0.013) showed an increased risk of CNS tumors. Infants born by vaginal forceps or vacuum delivery had a higher risk of CNS tumors compared to those born by spontaneous vaginal delivery (OR 1.35 [95% CI 1.12–1.62] P-value = 0.002). Additionally, offspring of Hispanic and non-Hispanic black mothers showed a higher risk of death (HR 1.45 [95% CI 1.16–1.80] P-value = 0.001; HR 1.53 [95% CI 1.12–2.09] P-value = 0.008, respectively). Infants born by cesarean had a higher risk of death compared to those delivered vaginally (HR 1.28 [95% CI 1.05–1.57] P-value = 0.016). These findings indicate the important role of maternal and perinatal characteristics in the etiology and survival of these clinically significant malignancies.

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.

Global Changes of 5-mC/5h-mC Ratio and Methylation of Adiponectin and Leptin Gene in Placenta Depending on Mode of Delivery

It was suggested that the epigenetic alterations of the placenta are associated with obesity, as well as the delivery mode. This study aimed to assess the effect of maternal outcome and delivery procedure on global placental DNA methylation status, as well as selected 5'-Cytosine-phosphate-Guanine-3' (CpG) sites in ADIPOQ and LEP genes. Global DNA methylation profile in the placenta was assessed using the 5-methylcytosine (5-mC) and 5-hydroxymethylcytosine (5-hmC) ratio evaluated with the ELISA, followed by target gene methylation patterns at selected gene regions which were determined using methylation-specific qPCR in 70 placentas from healthy, pregnant women with single pregnancy. We found no statistically significant differences in 5-mC/5-hmC ratio between intrapartum cesarean sections (CS) and vaginal deliveries (p = 0.214), as well as between elective cesarean sections and vaginal deliveries (p = 0.221). In intrapartum cesarean sections, the ADIPOQ demethylation index was significantly higher (the average: 1.75) compared to elective cesarean section (the average: 1.23, p = 0.010) and vaginal deliveries (the average: 1.23, p = 0.011). The LEP demethylation index did not significantly differ among elective CS, intrapartum CS, and vaginal delivery groups. The demethylation index of ADIPOQ correlated negatively with LEP in the placenta in the vaginal delivery group (r = -0.456, p = 0.017), but not with the global methylation. The methylation of a singular locus might be different depending on the mode of delivery and uterine contractions. Further studies should be conducted with locus-specific analysis of the whole genome to detect the methylation index of specific genes involved in metabolism.

Are There Epigenetic Oxytocin-Mediated Effects on the Mother and Infant during Physiological Childbirth?

INTRODUCTION

Studies have shown that long-term positive behavioural and physiological changes are induced in connection with vaginal, physiological birth, and skin-to-skin contact after birth in mothers and babies. Some of these effects are consistent with the effect profile of oxytocin. This scoping review explores whether epigenetic changes of the oxytocin gene and of the oxytocin receptor gene (OTR) are involved in these effects.

METHODS

We searched Pubmed, Medline, BioMed Central, Cochrane Library, OVID, and Web of Science for evidence of epigenetic changes in connection with childbirth in humans, with a particular focus on the oxytocin system.

RESULTS

There were no published studies identified that were related to epigenetic changes of oxytocin and its receptor in connection with labour, birth, and skin-to-skin contact after birth in mothers and babies. However, some studies were identified that showed polymorphisms of the oxytocin receptor influenced the progress of labour. We also identified studies in which the level of global methylation was measured in vaginal birth and caesarean section, with conflicting results. Some studies identified differences in the level of methylation of single genes linked to various effects, for example, immune response, metabolism, and inflammation. In some of these cases, the level of methylation was associated with the duration of labour or mode of birth. We also identified some studies that demonstrated long-term effects of mode of birth and of skin-to-skin contact linked to changes in oxytocin function.

CONCLUSION

There were no studies identified that showed epigenetic changes of the oxytocin system in connection with physiological birth. The lack of evidence, so far, regarding epigenetic changes did not exclude future demonstrations of such effects, as there was a definite role of oxytocin in creating long-term effects during the perinatal period. Such studies may not have been performed. Alternatively, the oxytocin linked effects might be indirectly mediated via other receptors and signalling systems. We conclude that there is a significant lack of research examining long-term changes of oxytocin function and long-term oxytocin mediated adaptive effects induced during physiological birth and skin-to-skin contact after birth in mothers and their infants.

Pediatrics Consequences of Caesarean Section-A Systematic Review and Meta-Analysis

BACKGROUND

Cesarean section is a surgical procedure, which is the most frequently performed in gynecology and obstetrics. It is commonly believed that an operative delivery is a less painful and safer mode of delivery, which translates into an increasing number of the procedures performed without medical indications. The maternal sequelae of cesarean sections are well elucidated and widely discussed in the literature, while long-term neonatal consequences still remain the issue of research and scientific dispute. The aim of the present paper was to perform a systematic review of current literature regarding pediatrics consequences of cesarean section.

METHODS

We reviewed available data from PubMed, Science Direct as well as Google Scholar bases concerning early and long-term neonatal sequelae of operative deliveries. The following key words were used: "cesarean section", "caesarean section", "neonatal outcomes", "respiratory disorders", "asthma", "obesity", "overweight", and "neurological disorders". A total of 1636 papers were retrieved out of which 27 were selected for the final systematic review whereas 16 articles provided data for meta-analysis. Statistical analyses were performed using RevMan 5.4. To determine the strength of association between the caesarean section and respiratory tract infections, asthma, diabetes type 1 as well as obesity the pooled odds ratios (OR) with the 95% confidence intervals (CI) were calculated.

RESULTS

Conducted meta-analyses revealed that caesarean section is a risk factor for respiratory tract infections (pooled OR = 1.30 95%CI 1.06-1.60, p = 0.001), asthma (pooled OR = 1.23 95%CI 1.14-1.33, p < 0.00001) as well as obesity (pooled OR = 1.35 95%CI 1.29-1.41, p < 0.00001) in offspring.

CONCLUSIONS

The results of the studies included indicated that children delivered by cesarean section more commonly developed respiratory tract infections, obesity and the manifestations of asthma than children delivered vaginally. The risk of developing diabetes mellitus type 1 or neurological disorders in offspring after caesarean section is still under discussion.

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.

Cesarean section and risk of childhood leukemia: a systematic review and meta-analysis

BACKGROUND

A large number of studies pointed that being delivered by cesarean section (CS) would affect the health outcomes of offspring, however, whether CS would affect the risk of childhood leukemia remained uncertain. This study conducted a meta-analysis to quantitatively evaluate whether being delivered by CS would influence the onset of childhood leukemia.

METHODS

PubMed, Embase and Web of Science databases were searched from 3rd June, 1950 to 13th October, 2019 to identify the literature, which examined the relationship between CS and childhood leukemia. This study used Newcastle-Ottawa Scale to assess the quality of literature. Subgroup analyses were conducted on region, mode of delivery, design of the study and number of confounders adjusted. Egger's test and Begg's test were performed to evaluate possible publication bias.

RESULTS

The pooled odds ratio (OR) estimates illustrated that children delivered by CS had a higher risk of developing leukemia [OR 1.10, 95% confidence interval (CI) 1.04-1.17, P = 0.002] and lymphoblastic leukemia (OR 1.12, 95% CI 1.03-1.23, P = 0.009), while a significant association for myeloid leukemia was not observed (OR 1.05, 95% CI 0.92-1.20, P = 0.451). Results of subgroup analyses indicated that elective CS would increase the risk of childhood lymphoblastic leukemia (OR 1.16, 95% CI 1.06-1.27, P = 0.002). However, a statistical relationship between emergency CS and lymphoblastic leukemia was not observed (OR 1.07, 95% CI 0.93-1.23, P = 0.364).

CONCLUSIONS

CS would increase the risk of childhood lymphoblastic leukemia. It is worth noting that subgroup analyses shows that elective CS rather than emergency CS increases the risk of lymphoblastic leukemia in offspring.

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.

Association of Birth by Cesarean Delivery With Obesity and Type 2 Diabetes Among Adult Women

Importance

Cesarean delivery is associated with an increased risk of childhood obesity in offspring. However, whether this increased risk also includes obesity-associated conditions remains unclear.

Objective

To evaluate the association of birth by cesarean delivery with offspring's risks of obesity and type 2 diabetes in adulthood.

Design, Setting, and Participants

This prospective cohort study compared the incidence of obesity and type 2 diabetes between birth by cesarean delivery and vaginal delivery among 33 226 women participating in the Nurses' Health Study II who were born between 1946 and 1964, with follow-up through the end of the 2013-2015 follow-up cycle. Participants' mothers provided information on mode of delivery and pregnancy characteristics. Participants provided information every 2 years on weight and diagnosis of type 2 diabetes. Relative risks of obesity and type 2 diabetes were estimated using log-binomial and proportional hazards regression accounting for maternal body mass index and other confounding factors. Statistical analysis was performed from June 2017 to December 2019.

Exposure

Birth by cesarean delivery compared with birth by vaginal delivery.

Main Outcomes and Measures

Risk of obesity and incidence of type 2 diabetes.

Results

At baseline, the participants' mean (SD) age was 33.8 (4.6) years (range, 24.0-44.0 years). A total of 1089 of the 33 226 participants (3.3%) were born by cesarean delivery. After 1 913 978 person-years of follow-up, 12 156 (36.6%) women were obese and 2014 (6.1%) had received a diagnosis of type 2 diabetes. Women born by cesarean delivery were more likely to be classified as obese and to have received a diagnosis of type 2 diabetes during follow-up. The multivariable-adjusted relative risk of obesity among women born by cesarean vs vaginal delivery was 1.11 (95% CI, 1.03-1.19). The multivariable-adjusted hazard ratio for type 2 diabetes among women born by cesarean vs vaginal delivery was 1.46 (95% CI, 1.18-1.81); this association remained significant after additional adjustment for participant's own body mass index (relative risk, 1.34 [95% CI, 1.08-1.67]). These associations persisted when analyses were restricted to women at low risk of cesarean delivery based on maternal characteristics.

Conclusions and Relevance

This study suggests that women born by cesarean delivery may have a higher risk than women born by vaginal delivery of being obese and developing type 2 diabetes during adult life.

Identification of differentially methylated candidate genes and their biological significance in IUGR neonates by methylation EPIC array

Background: Intrauterine growth restriction (IUGR) is a pregnancy-associated disease manifested by decreased growth rate of fetus than the normal genetic growth potential. It is associated with increased susceptibility to metabolic diseases later in life. Although the mechanisms underlying the origin of metabolic diseases are poorly understood, DNA methylation is a crucial investigation for the identification of epigenetic changes.Objectives: To assess the degree of change of DNA methylation in IUGR neonates and compare with that of appropriate for gestational age (AGA) neonates and to explore the differentially methylated candidate genes and their biological significance.Methods: This cohort study was conducted in the Neonatology Department of JIPMER during the period of November 2017 to December 2018. Forty each of IUGR and gestation matched AGA neonates were recruited. Umbilical cord blood samples were collected at birth. DNA was separated from the blood samples; and, using 5-mC DNA ELISA method, the percentage of genomic DNA methylated in these neonates was established. Data were expressed as mean ± standard deviation. Methylation EPIC array was performed to identify the differentially methylated candidate genes. David analysis was used to find out the functional annotation chart by KEGG pathway.Results: Genomic DNA methylation varied significantly between IUGR and AGA neonates (IUGR: 3.12 ± 1.24; AGA: 4.40 ± 2.03; p value: <.01). A global shift toward hypomethylation was seen in IUGR compared with AGA, targeted to regulatory regions of the genome, and specifically promoters. Pathway analysis identified deregulation of pathways involved in metabolic diseases. Altered methylation of PTPRN2 & HLADQB1 genes leads to dysregulation of T-cells and reactive oxygen species (ROS). These changes may lead to complications later among these neonates subjected to IUGR.Conclusion: Our findings show significant changes in the methylation pattern of genes among IUGR and AGA babies. Steps for correcting the changes may help in reducing later complications among IUGR babies.

Hematopoietic cellular aging is not accelerated during the first 2 years of life in children born preterm

BACKGROUND

Prematurity in itself and exposure to neonatal intensive care triggers inflammatory processes and oxidative stress, leading to risk for disease later in life. The effects on cellular aging processes are incompletely understood.

METHODS

Relative telomere length (RTL) was measured by qPCR in this longitudinal cohort study with blood samples taken at birth and at 2 years of age from 60 children (16 preterm and 44 term). Viral respiratory infections the first year were evaluated. Epigenetic biological DNA methylation (DNAm) age was predicted based on methylation array data in 23 children (11 preterm and 12 term). RTL change/year and DNAm age change/year was compared in preterm and term during the 2 first years of life.

RESULTS

Preterm infants had longer telomeres than term born at birth and at 2 years of age, but no difference in telomere attrition rate could be detected. Predicted epigenetic DNAm age was younger in preterm infants, but rate of DNAm aging was similar in both groups.

CONCLUSIONS

Despite early exposure to risk factors for accelerated cellular aging, children born preterm exhibited preserved telomeres. Stress during the neonatal intensive care period did not reflect accelerated epigenetic DNAm aging. Early-life aging was not explained by preterm birth.

IMPACT

Preterm birth is associated with elevated disease risk later in life. Preterm children often suffer from inflammation early in life. Stress-related telomere erosion during neonatal intensive care has been proposed. Inflammation-accelerated biological aging in preterm is unknown. We find no accelerated aging due to prematurity or infections during the first 2 years of life.

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.

DNA methylation profiles of genes associated with angiogenesis in the samples of placenta in pregnancies complicated by intrauterine growth restriction

BACKGROUND

Impairment in placental angiogenesis is blamed for the etiopathogenesis of intrauterine growth restriction (IUGR).

AIM

To assess the genes related to angiogenesis in placental biopsies of pregnancies complicated by IUGR that could be aberrantly methylated and adversely affect placental angiogenesis.

METHODS

The methylation profiles of soluble fms-like tyrosine kinase-1 (sFLT-1), vascular endothelial growth factor (VEGF), and the placental growth factor (PIGF) were evaluated using Illumina MiSeq™ System in placental biopsies from term IUGR pregnancies without preeclampsia (n  =  18) and healthy controls (n  =  17). DNA was isolated from samples of tissue collected from the fetal side of the placenta. In the targeted regions, we have identified 30, 24, and 29 CpG islands (CpGi) within sFLT-1, VEGF and PIGF genes, respectively. CpGi which are most methylated in the promoter regions of three genes were selected for the study from the database http://www.ensembl.org.

RESULT(S)

IUGR fetuses had significantly lower placental and fetal birth weight than controls. The promoter of sFLT-1 at three CpGi and VEGF at six CpGi were the regions with significant methylation differences between IUGR and control placentas. sFLT-1 was hypermethylated at 265 and 352 CpGi; however, hypermethylation was lower in IUGR group compared to control group at this position. sFLT-1 was hypomethylated at 456 CpGi in IUGR group and hypermethylated at the same region in control group. VEGF was hypomethylated at 668, 703, and 710 CpGi in control and IUGR groups; however, hypomethylation at these positions was significantly higher in control group compared to IUGR. 776, 845, and 863 CpGi of VEGF promoter were significantly hypermethylated in IUGR group whereas hypomethylated in control group. The methylation profile of PIGF did not differ between the groups. After adjustment for the factors known to affect fetal birth weight, DNA methylation of VEGF 668 CpGi had a significant negative association with fetal birth weight in the control and the IUGR group and a positive association with IUGR pregnancies.

CONCLUSION(S)

Our results do not support the hypothesis that altered DNA methylation in the placental angiogenic genes is a major mechanism generally involved in IUGR. Only a specific region (at 668 CpGi) corresponding to the promoter of VEGF may serve as an epigenetic marker of IUGR and may be involved in the mechanism of IUGR. Large sample-sized studies are needed to understand the effects of DNA methylation on placental gene function and how they might influence fetal growth.

The interaction between gut microbiome and nutrients on development of human disease through epigenetic mechanisms

Early environmental exposure is recognized as a key factor for long-term health based on the Developmental Origins of Health and Disease hypothesis. It considers that early-life nutrition is now being recognized as a major contributor that may permanently program change of organ structure and function toward the development of diseases, in which epigenetic mechanisms are involved. Recent researches indicate early-life environmental factors modulate the microbiome development and the microbiome might be mediate diet-epigenetic interaction. This review aims to define which nutrients involve microbiome development during the critical window of susceptibility to disease, and how microbiome modulation regulates epigenetic changes and influences human health and future prevention strategies.

Intergenerational transmission of depression: clinical observations and molecular mechanisms

Maternal mental illness can have a devastating effect during the perinatal period, and has a profound impact on the care that the baby receives and on the relationships that the baby forms. This review summarises clinical evidence showing the effects of perinatal depression on offspring physical and behavioural development, and on the transmission of psychopathology between generations. We then evaluate a number of factors which influence this relationship, such as genetic factors, the use of psychotropic medications during pregnancy, the timing within the perinatal period, the sex of the foetus, and exposure to maltreatment in childhood. Finally, we examine recent findings regarding the molecular mechanisms underpinning these clinical observations, and identify relevant epigenetic and biomarker changes in the glucocorticoid, oxytocin, oestrogen and immune systems, as key biological mediators of these clinical findings. By understanding these molecular mechanisms in more detail, we will be able to improve outcomes for both mothers and their offspring for generations.

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.

Skin-to-skin contact the first hour after birth, underlying implications and clinical practice

AIM

This paper integrates clinical expertise to earlier research about the behaviours of the healthy, alert, full-term infant placed skin-to-skin with the mother during the first hour after birth following a noninstrumental vaginal birth.

METHOD

This state-of-the-art article forms a link within the knowledge-to-action cycle, integrating clinical observations and practice with evidence-based findings to guide clinicians in their work to implement safe uninterrupted skin-to-skin contact the first hours after birth.

RESULTS

Strong scientific research exists about the importance of skin-to-skin in the first hour after birth. This unique time for both mother and infant, individually and in relation to each other, provides vital advantages to short- and long-term health, regulation and bonding. However, worldwide, clinical practice lags. A deeper understanding of the implications for clinical practice, through review of the scientific research, has been integrated with enhanced understanding of the infant's instinctive behaviour and maternal responses while in skin-to-skin contact.

CONCLUSION

The first hour after birth is a sensitive period for both the infant and the mother. Through an enhanced understanding of the newborn infant's instinctive behaviour, practical, evidence-informed suggestions strive to overcome barriers and facilitate enablers of knowledge translation. This time must be protected by evidence-based routines of staff.

Caesarean section and infant formula feeding are associated with an earlier age of onset of multiple sclerosis

Mode of delivery and lactation are among the earliest factors influencing gut microbiota composition and potentially MS risk, but their contribution to MS susceptibility has been controversial. We investigated whether these factors could influence age at MS onset (AAO) on 2055 RRMS patients (mean age 28.4 years). Patients born by means of a caesarean section (10.9%) had an earlier AAO than those born through natural delivery (-5.2 years, p < 0.001). Patients fed with infant formula had an earlier AAO compared to patients breastfed, particularly considering those breastfed for at least 6 months (-4.2 years, p < 0.001). The association of vaginal delivery and natural breastfeeding with a later AAO of MS was particularly apparent in patients without a family history of MS, while disappeared in patients with familiarity for MS. The results suggest these modifiable environmental factors which act at the population level may have an influence on the onset of the disease.

Investigating Caesarean Section Birth as a Risk Factor for Childhood Overweight

BACKGROUND

Caesarean section birth may be associated with overweight in childhood; however, findings to date have been inconsistent. This study explored the association of caesarean section vs. vaginal birth with childhood overweight in Vietnam.

METHODS

This longitudinal cohort study explored the association of delivery mode with overweight, obesity, and overweight/or obesity at 8 years of age in children (n = 1937) across 20 sites in Vietnam, using Young Lives longitudinal cohort study data. Categories were defined using BMI z-scores in relationship to the World Health Organization (WHO) reference median: overweight >1 and <2 standard deviations (SD) above WHO reference median, obese >2 SD, and overweight/or obese >1 SD. Individual questionnaire data collected sociodemographic information and pregnancy/birth information through face-to-face interviews with mothers/caregivers. Anthropometric measurements for mother and child were collected at baseline and at 8 years for children.

RESULTS

Adjusted multivariable logistic models revealed a twofold increase in odds at age 8 years of overweight [odds ratio (OR) = 1.8, 95% confidence interval (95% CI) 1.03-3.2, p = 0.039], obese (OR = 2.2, 95% CI 1.2-4.0, p = 0.014), or overweight/or obese (OR = 2.1, 95% CI 1.3-3.3, p = 0.002) for children born through caesarean section compared with vaginal birth. Children born through planned caesarean section (adjusted OR = 2.3, 95% CI 1.2-4.1, p < 0.001) and unplanned caesarean section (adjusted OR = 1.9, 95% CI 1.1-3.5, p = 0.03) had similar increased odds of overweight/or obesity compared with children born through vaginal birth.

CONCLUSIONS

These findings suggest that there may be an association between caesarean section and childhood overweight even after adjustment for confounders. Further research is needed to explore the underlying mechanisms of this finding.

Pathways linking caesarean delivery to early health in a dual burden context: Immune development and the gut microbiome in infants and children from Galápagos, Ecuador

OBJECTIVES

Global increases in caesarean deliveries are exposing more infants to perinatal environments that are evolutionarily novel and potentially increasing their risks for inflammatory conditions. Yet, the pathways linking caesareans to later health outcomes are not well understood, particularly in dual burden contexts. We test two of the hypothesized pathways, altered immune function and gut microbiota, which may link delivery mode to later health outcomes and test whether these associations persist when controlling for postnatal nutritional and pathogenic exposures.

METHODS

Data come from infants, aged 0 to 2 (n = 41), and young children, aged 2 to 11 (n = 135), from the Galápagos, Ecuador. Differences in morbidity, C-reactive protein (CRP), and gut microbiota by delivery type were tested using linear and logistic regression models adjusted for nutritional and pathogenic exposures and infant age.

RESULTS

Over half of infants and over 40% of children were delivered by caesarean. Morbidity and CRP did not differ between infants or children born by caesarean or vaginally. Microbial taxa abundance differed by delivery mode. Infants born by caesarean had a higher abundance of Firmicutes and a lower relative abundance of Bacteroidales. Children born by caesarean had a higher abundance of Proteobacteria and Enterobacteriales. These differences remained after adjustment for environmental exposure.

CONCLUSIONS

Caesarean delivery is associated with differences in gut microbiota across childhood even in this dual burden context. Our results highlight the importance of examining caesarean delivery across diverse contexts to better understand the impact of perinatal interventions on short- and longer-term health outcomes.

Relations between mode of birth delivery and timing of developmental milestones and adiposity in preadolescence: A retrospective study

BACKGROUND

Cesarean delivery (CS) is an increasingly common mode of delivery comprising over 30% of all deliveries in the U.S. The long-term impact of this delivery mode on child development remains unclear.

AIMS

We investigated the relationship between mode of delivery (vaginal vs. CS) and timing of developmental milestones and adiposity in preadolescence, as well as additional milestones beyond motor/language development including toilet training, dressing, and feeding self.

STUDY DESIGN

This study utilized a retrospective survey given to a parent/guardian and dual energy x-ray absorptiometry in preadolescence, respectively. A composite z-score was calculated based on nine questions pertaining to developmental milestones i.e., parent-reported age for supporting head by self, rolling over, sitting up, standing, walking, talking, toilet-training, dressing, and feeding self.

SUBJECTS

7-10-year-old (N = 104) children in East-Central Illinois.

OUTCOME MEASURES

Composite z-score for timing of attainment of developmental milestones, mode of delivery, and preadolescent adiposity.

RESULTS

Vaginally-born children had a lower composite z-score, signifying earlier attainment of developmental milestones, relative to both emergency and planned CS-born children. Further, elective CS-born children had greater adiposity in preadolescence, relative to vaginal and emergency cesarean-section born children.

CONCLUSIONS

These findings suggest relationships between delivery mode, developmental milestones, and obesity in preadolescence. Additionally, they provide novel insights into the differential impact of elective versus emergency CS.

Parturition and the perinatal period: can mode of delivery impact on the future health of the neonate?

Caesarean section and instrumental delivery rates are increasing in many parts of the world for a range of cultural and medical reasons, with limited consideration as to how 'mode of delivery' may impact on childhood and long-term health. However, babies born particularly by pre-labour caesarean section appear to have a subtly different physiology from those born by normal vaginal delivery, with both acute and chronic complications such as respiratory and cardio-metabolic morbidities being apparent. It has been hypothesized that inherent mechanisms within the process of labour and vaginal delivery, far from being a passive mechanical process by which the fetus and placenta are expelled from the birth canal, may trigger certain protective developmental processes permissive for normal immunological and physiological development of the fetus postnatally. Traditionally the primary candidate mechanism has been the hormonal surges or stress response associated with labour and vaginal delivery, but there is increasing awareness that transfer of the maternal microbiome to the infant during parturition. Transgenerational transmission of disease traits through epigenetics are also likely to be important. Interventions such as probiotics, neonatal gut seeding and different approaches to clinical care have potential to influence parturition physiology and improve outcomes for infants.

The effect of medical and operative birth interventions on child health outcomes in the first 28 days and up to 5 years of age: A linked data population-based cohort study

BACKGROUND

Spontaneous vaginal birth rates are decreasing worldwide, while cesarean delivery, instrumental births, and medical birth interventions are increasing. Emerging evidence suggests that birth interventions may have an effect on children's health. Therefore, the aim of our study was to examine the association between operative and medical birth interventions on the child's health during the first 28 days and up to 5 years of age.

METHODS

In New South Wales (Australia), population-linked data sets were analyzed, including data on maternal characteristics, child characteristics, mode of birth, interventions during labor and birth, and adverse health outcomes of the children (ie, jaundice, feeding problems, hypothermia, asthma, respiratory infections, gastrointestinal disorders, other infections, metabolic disorder, and eczema) registered with the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Australian Modification codes. Logistic regression analyses were performed for each adverse health outcome.

RESULTS

Our analyses included 491 590 women and their children; of those 38% experienced a spontaneous vaginal birth. Infants who experienced an instrumental birth after induction or augmentation had the highest risk of jaundice, adjusted odds ratio (aOR) 2.75 (95% confidence interval [CI] 2.61-2.91) compared with spontaneous vaginal birth. Children born by cesarean delivery were particularly at statistically significantly increased risk for infections, eczema, and metabolic disorder, compared with spontaneous vaginal birth. Children born by emergency cesarean delivery showed the highest association for metabolic disorder, aOR 2.63 (95% CI 2.26-3.07).

CONCLUSION

Children born by spontaneous vaginal birth had fewer short- and longer-term health problems, compared with those born after birth interventions.

Treatment with nitric oxide in the neonatal intensive care unit is associated with increased risk of childhood cancer

AIM

This study aimed to determine whether neonatal intensive care therapies increase the risk of carcinogenesis in childhood.

METHODS

This study used population-based data on 1 072 957 infants born in New South Wales, Australia, between 2000 and 2011 and multivariate logistic regression to examine any associations between therapies used in the neonatal intensive care unit and diagnoses of cancer until mid 2012.

RESULTS

A total of 1126 of 1 072 957 (0.1%) children were diagnosed with cancer. Cancer risk was significantly increased by preterm birth (gestation <37 weeks; adjusted odds ratio (aOR) 1.3 (95% confidence interval: 1.0-1.6), birth weight ≥4 kg (aOR 1.4, 1.2-1.6) and caesarean delivery (aOR 1.2, 1.1-1.4). Extremely preterm (<28 weeks of gestation) infants were more likely to develop hepatic tumours (aOR 12.7, 3.3-48.3) than term infants. The only therapy used in the neonatal intensive care that was independently associated with an increased risk of cancer was nitric oxide (aOR 8.6, 4.3-17.4). Eight of the 790 (1%) infants treated with nitric oxide developed cancer (gestation range 30-41 weeks, age of cancer diagnosis: four months-five years).

CONCLUSION

Treatment with nitric oxide was associated with a higher risk of childhood cancer. These findings require further research.

Moderating effect of mode of delivery on the genetics of intelligence: Explorative genome-wide analyses in ALSPAC

INTRODUCTION

Intelligence is a core construct of individual differences in cognitive abilities and a strong predictor of important life outcomes. Within recent years, rates of cesarean section have substantially increased globally, though little is known about its effect on neurodevelopmental trajectories. Thus, we aimed to investigate the influence of delivery by cesarean section on the genetics of intelligence in children.

METHODS

Participants were recruited through the Avon Longitudinal Study of Parents and Children (ALSPAC). Intelligence was measured by the Wechsler Intelligence Scale for Children (WISC). Genotyping was performed using the Illumina Human Hap 550 quad genome-wide SNP genotyping platform and was followed by imputation using MACH software. Genome-wide interaction analyses were conducted using linear regression.

RESULTS

A total of 2,421 children and 2,141,747 SNPs were subjected to the genome-wide interaction analyses. No variant reached genome-wide significance. The strongest interaction was observed at rs17800861 in the GRIN2A gene (β = -3.43, 95% CI = -4.74 to -2.12, p = 2.98E-07). This variant is predicted to be located within active chromatin compartments in the hippocampus and may influence binding of the NF-kappaB transcription factor.

CONCLUSIONS

Our results may indicate that mode of delivery might have a moderating effect on genetic disposition of intelligence in children. Studies of considerable sizes (>10,000) are likely required to more robustly detect variants governing such interaction. In summary, the presented findings prompt the need for further studies aimed at increasing our understanding of effects various modes of delivery may have on health outcomes in children.

Association of Elective and Emergency Cesarean Delivery With Early Childhood Overweight at 12 Months of Age

IMPORTANCE

Global cesarean delivery (CD) rates have more than doubled over the past 2 decades, with an increasing contribution from elective CDs. Cesarean delivery has been linked to early childhood overweight and obesity, but limited studies have examined elective and emergency CDs separately.

OBJECTIVE

To investigate whether elective or emergency CD was associated with risk of early childhood overweight.

DESIGN, SETTING, AND PARTICIPANTS

Data were drawn from the Growing Up in Singapore Toward Healthy Outcomes (GUSTO) study, an ongoing prospective mother-child birth cohort study. Participants were pregnant women aged 18 years or older with homogeneous parental ethnic background in their first trimester recruited between June 2009 and September 2010 (n = 1237) at 2 major public hospitals in Singapore. Those with type 1 diabetes or undergoing chemotherapy or psychotropic drug treatment were excluded. Data analysis commenced in October 2017.

EXPOSURES

Delivery mode obtained from clinical records. Elective and emergency CD examined separately against vaginal delivery as reference.

MAIN OUTCOMES AND MEASURES

Body mass index-for-age z scores at age 12 months calculated based on 2006 World Health Organization Child Growth Standards from infant weight and recumbent crown-heel length measurements taken between December 2010 and April 2012. High body mass index status at risk of overweight was defined as a z score of more than 1 SD and less than or equal to 2 SDs. Overweight was defined as a z score of more than 2 SDs.

RESULTS

Among 727 infants analyzed (51.2% [372] male), 30.5% (222) were born via CD, of which 33.3% (74) were elective. Prevalence of at risk of overweight and overweight at age 12 months was 12.2% (89) and 2.3% (17), respectively. Elective CD was significantly associated with at risk of overweight or overweight at age 12 months after adjusting for maternal ethnicity, age, education, parity, body mass index, antenatal smoking, hypertensive disorders of pregnancy, gestational diabetes, and sex-adjusted birth weight-for-gestational age (odds ratio, 2.05; 95% CI, 1.08-3.90; P = .03). The association persisted after further adjustment for intrapartum antibiotics and first 6 months infant feeding, 2 potential mediators of early childhood overweight and obesity (odds ratio, 2.02; 95% CI, 1.05-3.89; P = .04). No significant associations were found for emergency CD. Analysis with multiple imputation for missing covariates yielded similar results.

CONCLUSIONS AND RELEVANCE

Choice of delivery mode may influence risk of early childhood overweight. Clinicians are encouraged to discuss potential long-term implications of elective CD on child metabolic outcomes with patients who intend to have children.

Inflammation-related epigenetic risk and child and adolescent mental health: A prospective study from pregnancy to middle adolescence

In 785 mother-child (50% male) pairs from a longitudinal epidemiological birth cohort, we investigated associations between inflammation-related epigenetic polygenic risk scores (i-ePGS), environmental exposures, cognitive function, and child and adolescent internalizing and externalizing problems. We examined prenatal and postnatal effects. For externalizing problems, one prenatal effect was found: i-ePGS at birth associated with higher externalizing problems (ages 7-15) indirectly through lower cognitive function (age 7). For internalizing problems, we identified two effects. For a prenatal effect, i-ePGS at birth associated with higher internalizing symptoms via continuity in i-ePGS at age 7. For a postnatal effect, higher postnatal adversity exposure (birth through age 7) associated with higher internalizing problems (ages 7-15) via higher i-ePGS (age 7). Hence, externalizing problems were related mainly to prenatal effects involving lower cognitive function, whereas internalizing problems appeared related to both prenatal and postnatal effects. The present study supports a link between i-ePGS and child and adolescent mental health.

Short-term and long-term effects of caesarean section on the health of women and children

A caesarean section (CS) can be a life-saving intervention when medically indicated, but this procedure can also lead to short-term and long-term health effects for women and children. Given the increasing use of CS, particularly without medical indication, an increased understanding of its health effects on women and children has become crucial, which we discuss in this Series paper. The prevalence of maternal mortality and maternal morbidity is higher after CS than after vaginal birth. CS is associated with an increased risk of uterine rupture, abnormal placentation, ectopic pregnancy, stillbirth, and preterm birth, and these risks increase in a dose-response manner. There is emerging evidence that babies born by CS have different hormonal, physical, bacterial, and medical exposures, and that these exposures can subtly alter neonatal physiology. Short-term risks of CS include altered immune development, an increased likelihood of allergy, atopy, and asthma, and reduced intestinal gut microbiome diversity. The persistence of these risks into later life is less well investigated, although an association between CS use and greater incidence of late childhood obesity and asthma are frequently reported. There are few studies that focus on the effects of CS on cognitive and educational outcomes. Understanding potential mechanisms that link CS with childhood outcomes, such as the role of the developing neonatal microbiome, has potential to inform novel strategies and research for optimising CS use and promote optimal physiological processes and development.

Gene-specific DNA methylation in newborns in response to folic acid supplementation during the second and third trimesters of pregnancy: epigenetic analysis from a randomized controlled trial

Background

Emerging evidence suggests that maternal folate status can impact cognitive development in childhood. Folate-dependent DNA methylation may provide a biological mechanism to link folate status during pregnancy with cognition in the offspring.

Objective

The objective was to investigate the effect of continued folic acid (FA) supplementation beyond the first trimester of pregnancy on DNA methylation in cord blood of epigenetically controlled genes related to brain development and function.

Design

Using available cord blood samples (n = 86) from the Folic Acid Supplementation in the Second and Third Trimesters (FASSTT) trial in pregnancy, we applied pyrosequencing techniques to analyze cord blood DNA at 9 candidate loci known to be regulated by methylation, including some previously implicated in observational studies: the widely dispersed retrotransposon long interspersed nuclear element-1 (LINE-1) and 8 single-copy loci (RBM46, PEG3, IGF2, GRB10, BDNF, GRIN3B, OPCML, and APC2).

Results

The newborns of mothers who received ongoing FA (400 µg/d) through the second and third trimesters, compared with placebo, had significantly lower overall DNA methylation levels at LINE-1 (56.3% ± 1.7% compared with 57.2% ± 2.1%; P = 0.024), IFG2 (48.9% ± 4.4% compared with 51.2% ± 5.1%; P = 0.021), and BDNF (2.7% ± 0.7% compared with 3.1% ± 0.8%; P = 0.003). The effect of FA treatment on DNA methylation was significant only in female offspring for IGF2 (P = 0.028) and only in males for BDNF (P = 0.012). For GRB10 and GRIN3B, we detected no effect on overall methylation; however, individual cytosine-phosphate-guanine sites showed significant DNA methylation changes in response to FA.

Conclusions

Continued supplementation with FA through trimesters 2 and 3 of pregnancy results in significant changes in DNA methylation in cord blood of genes related to brain development. The findings offer a potential biological mechanism linking maternal folate status with neurodevelopment of the offspring, but this requires further investigation using a genome-wide approach. This trial was registered at www.isrctn.com as ISRCTN19917787.

An Introduction to Epigenetics

Epigenetics refers to the heritable information that is exclusive of DNA. Several syndromes have been found to occur as the result of the process of epigenetics. This process causes changes in the expression of genes, without changing the actual DNA sequence. The factors influencing this process include both internal and external triggers, leading to modulation of the epigenome through different mechanisms. This article aims to describe how the process of epigenetics gives rise to the multitude of possible syndromes seen in neonates. The article will also discuss the role of assisted reproductive technology may play in epigenetic changes when compared with the naturally conceived embryo.

Epigenome-wide study for the offspring exposed to maternal HBV infection during pregnancy, a pilot study

BACKGROUND & AIM

Hepatitis B virus (HBV) can be transmitted to infants, and is related to infants' later disease risk. Epigenetic change (such as DNA methylation) may be mechanism underlying the relationship. In this study, we aimed to investigate whether prenatal HBV infection could alter DNA methylation status in newborns.

METHOD

We selected 12 neonates with intrauterine HBV infection whose mothers were HBsAg-positive during pregnancy, relative to 12 HBV-free neonates with HBsAg-negative mothers. The pattern of genome-wide DNA methylation in the umbilical cord blood was investigated by Illumina Infinium Human Methylation 450K BeadChip.

RESULT

The average level of global methylation in infected neonates exposed to maternal HBV infection was not significantly different from controls. However, after adjusting for multiple comparisons, we found differential significance in the cases group compared to the controls for 663 CpG sites, associated with 534 genes. Among these sites, 53.85% (357/663) had decreased methylation (ΔM < 0) and 46.15% (306/663) had increased methylation (ΔM > 0). The average percentage change (Δβ) in methylation ranged from -46% to 36%. Validated by pyrosequencing, we identified 4 significantly differentially methylated CpG sites in the KLHL35 gene and additional CpGs for the CPT1B gene. These genes play a role in the development of hepatocellular and colorectal carcinoma and fatty acid oxidation, suggesting the candidature of these genes in HBV related disease.

CONCLUSION

Prenatal HBV exposure, even without malformation or preterm birth, may alter the epigenome profile in newborns. We identified a set of genes with differentially methylated CpG sites presented in the cord blood of HBV-infected newborns with HBsAg-positive mothers, demonstrating that DNA methylation status at birth can be used as a biomarker of prenatal exposure. These DNA methylation differences suggest a possible role for epigenetic processes in neonatal development in response to prenatal HBV exposure.

The Elevated Rate of Cesarean Section and Its Contribution to Non-Communicable Chronic Diseases in Latin America: The Growing Involvement of the Microbiota

The current recommendation of the World Health Organization (WHO) regarding cesarean section (C-section) is that this clinical practice should be carried out only under specific conditions, when the health or life of the mother/newborn dyad is threatened, and that its use should not exceed 10-15% of the total deliveries. However, over the last few decades, the frequency of C-section delivery in medium- and high-income countries has rapidly increased worldwide. This review describes the evolution of this procedure in Latin American countries, showing that today more than half of newborns in the region are delivered by C-section. Given that C-section delivery is more expensive than vaginal delivery, its use has increased more rapidly in the private than the public sector; nevertheless, the prevalence of C-section deliveries in the public sector is higher than the WHO's recommendations and continues to increase, representing a growing challenge for Latin America. Although the medium- and long-term consequences of C-section delivery, as opposed to vaginal delivery, on the infant health are unclear, epidemiological studies suggest that it is associated with higher risk of developing asthma, food allergy, type 1 diabetes, and obesity during infancy. These findings are important, as the incidence of these diseases in the Latin American pediatric population is also increasing, particularly obesity. Although the link between these diseases and delivery mode remains controversial, recent studies indicate that the establishment of the gut microbiota is delayed in infants born by C-section during the postnatal period, i.e., during a critical developmental window for the maturation of the newborn's immune system. This delay may favor the subsequent development of inflammatory and metabolic disorders during infancy. Accordingly, from a public health perspective, it is important to slow down and eventually reverse the pattern of increased C-section use in the affected populations.