High risk of necrotising enterocolitis in term-born neonates with CHD delivered by caesarean section: a case-control study

OBJECTIVE

Necrotising enterocolitis is linked with altered intestinal microbiota, and caesarean birth is associated with imbalance of newborn intestinal microbiome. We aimed to investigate the role of delivery mode (vaginal or caesarean) and gestational age in the development of necrotising enterocolitis among term-born neonates (≥ 37 weeks) with CHD.

METHODS

Case-control study. We studied all newborns with CHD who underwent cardiac surgery during the neonatal (≤ 28 days of age) period, between 2007 and 2017. Totally, 60 cases of necrotising enterocolitis were matched (by year of birth and type of congenital heart lesion) with 180 controls (1:3 ratio). Multivariable conditional logistic regression was used to assess the study question.

RESULTS

The overall prevalence of necrotising enterocolitis was 6.3% in term-born newborns with CHD. Neonates with a left-ventricular outflow tract lesion or single ventricle lesion accounted for 55% (n = 33) of cases. 62% (n = 37) cases were in the modified Bell's stage 2 or more for necrotising enterocolitis classification. In multivariable modelling, gestational age at birth was not associated with the development of necrotising enterocolitis [adjusted odds ratio per week increase, 95% confidence interval: 1.20 (0.90-1.60)]. Birth by caesarean delivery (compared to vaginal) was strongly associated with development of necrotising enterocolitis [adjusted odds ratio (95% confidence interval): 2.64 (1.31-5.29)]. We failed to identify an association between preoperative enteral nutrition and necrotising enterocolitis.

CONCLUSION

This study showed a high risk of necrotising enterocolitis in newborns with critical CHD born via caesarean. This information is important given the high prevalence of planned birth by caesarean in newborns with CHD.

Birth triggers an inflammatory response in the neonatal periphery and brain

Birth is preceded by inflammation at the fetal/maternal interface. Additionally, the newborn experiences stimuli that under any other circumstance could elicit an immune response. It is unknown, however, whether birth elicits an inflammatory response in the newborn that extends to the brain. Moreover, it is unknown whether birth mode may alter such a response. To study these questions, we first measured corticosterone and pro- and anti-inflammatory cytokines in plasma of mouse offspring at several timepoints spaced closely before and after a vaginal or Cesarean birth. We found highest levels of IL-6 one day before birth and surges in corticosterone and IL-10 just after birth, regardless of birth mode. We next examined the neuroimmune response by measuring cytokine mRNA expression and microglial number and morphology in the paraventricular nucleus of the hypothalamus and hippocampus around the time of birth. We found a marked increase in TNF-α expression in both brain regions a day after birth, and rapid increases in microglial cell number in the first three days postnatal, with subtle differences by birth mode. To test whether the association between birth and cytokine production or expansion of microglia is causal, we manipulated birth timing. Remarkably, advancing birth by a day advanced the increases in all of the markers tested. Thus, birth triggers an immune response in the body and brain of offspring. Our results may provide a mechanism for effects of birth (e.g., acute changes in cell death and neural activation) previously reported in the newborn brain.

Vaginal Delivery Is Associated with Neurochemical Evidence of Increased Neuroaxonal Remodelling in Infants from the KUNO-Kids Health Study: Cross-Sectional Analysis

AIM

Little is known about neonatal brain plasticity or the impact of birth mode on neurointegrity. As a reflection of neuroaxonal damage, the neuronal structural protein neurofilament light chain (NfL) has emerged as a highly specific biomarker. Our purpose was to test the hypothesis that vaginal delivery is associated with increased NfL in neonates.

METHODS

NfL concentrations were measured using single-molecule array immunoassay in umbilical cord serum from healthy term neonates enrolled in the prospective KUNO-Kids Health Study. NfL values were investigated for independent influencing factors using linear and logistic models, followed by post hoc propensity score-matching.

RESULTS

Of 665 neonates, n = 470 (70.7%) were delivered vaginally and n = 195 (29.3%) by cesarean section. Median serum NfL was significantly higher after vaginal delivery 14.4 pg/mL (11.6-18.5) compared to primary 7.5 pg/mL (6.1-8.9) and secondary cesarean delivery 9.3 pg/mL (7.5-12.0). Multivariable logistic regression models showed delivery mode and gestational age to be independently associated with NfL. Propensity score-matching analysis confirmed that assisted vaginal delivery generated higher NfL compared to vaginal (non-assisted), while lowest levels were associated with cesarean section.

INTERPRETATION

Our data confirm the significant impact of birth mode on neonatal NfL levels. The persistence of these differences and their potential long-term impact have yet to be investigated.

Retrospective evaluation of attempted vaginal deliveries in dichorionic twin pregnancies

Purpose

Numbers of planned cesarean deliveries are increasing in twin pregnancies, despite the lack of evidence for this approach, and the second twin is thought to be at risk for a poorer outcome. The aim of this study was to examine whether twins have a poorer outcome if an attempted vaginal delivery is changed to a cesarean section or combined delivery.

Methods

This retrospective data analysis included all women with dichorionic twin pregnancies attempting vaginal delivery over a 10-year period. Outcome parameters for the first and second twins relative to their mode of birth were compared. A correlation model between the interdelivery time interval and Apgar scores was calculated. Subgroup analyses assessing the birth mode of the first and second twins were conducted.

Results

A total of 248 women were enrolled in the study. The second twins had significantly lower values for outcome parameters, such as umbilical artery cord pH and Apgar scores in comparison with the first twins (P < 0.01). The subgroup analysis of birth modes in first and second twins showed a significantly poorer outcome in the cesarean section and combined delivery group (P < 0.05). The interdelivery time interval was significantly longer in the second twin cesarean section group (P < 0.01). There was no significant correlation between the interdelivery time intervals and Apgar scores (P > 0.05).

Conclusion

Although outcome parameters were significantly lower in second twins and twins born via secondary cesarean section, the clinical relevance of this appears to be negligible.

Gut Microbiota Composition in Healthy Japanese Infants and Young Adults Born by C-Section

Our gut microbiome plays a fundamental role in our health and disease. The microbial colonization of human gut begins immediately at birth and is an indispensable natural process that modulates our physiology and immunity. Recent studies are elegantly revealing how and when these microbes colonize the gut and what elements could potentially influence this natural phenomenon. The vertical mother-to-baby transmission of microbes is a crucial factor for normal development and maturation of newborn's immune, metabolic as well as neurological health. This important and delicate process of gut microbiota development may be impacted by various factors such as birth mode, type of feeding, gestational age at birth, antibiotics exposure in early life, surrounding environment and hygiene settings, and so on. Perturbations in early life gut microbial colonization have been associated with the development of several diseases such as diabetes, obesity, asthma, allergies, celiac disease, neurodevelopmental disorders, and so on. However, it remains unclear whether predisposition to these diseases is due to the lack of acquisition of the mother's (vaginal and perianal) microbes during birth or because of abnormal exposure to unsolicited bacteria. Hence, studies are required to scrutinize the colonization pattern of infant gut microbiome in context to birth mode and also to elucidate how long these differences could persist. In these contexts, we review and discuss some of the findings obtained from recent investigation of the gut microbiota composition in healthy Japanese infants and young adults born vaginally or by C-section.

Microbial Ecology of the Human Skin

This review article on the skin microbiota was written in response to recent advances that transitioned from culture methods to PCR amplification and sequencing of bacterial and fungal genes as a result of the Human Microbiome Project. This transition enables the investigation of the full diversity of microorganisms inhabiting human skin. The skin provides a range of habitats with different microbiota associated with the three major regions of the skin, namely the moist axilla, perineum, and toe webs; oily or sebaceous head, neck, and trunk; and dry forearms and legs. These new culture-independent tools are revealing the diversity of the human skin microbiota in the different locations of the body and with skin depth. These tools should lead to a better understanding of the state of homeostasis between the microbiota and the host and the overall functionality of that microbiota.

Viromes of one year old infants reveal the impact of birth mode on microbiome diversity

Establishing a diverse gut microbiota after birth is being increasingly recognised as important for preventing illnesses later in life. It is well established that bacterial diversity rapidly increases post-partum; however, few studies have examined the infant gut virome/phageome during this developmental period. We performed a metagenomic analysis of 20 infant faecal viromes at one year of age to determine whether spontaneous vaginal delivery (SVD) or caesarean section (CS) influenced viral composition. We find that birth mode results in distinctly different viral communities, with SVD infants having greater viral and bacteriophage diversity. We demonstrate that CrAssphage is acquired early in life, both in this cohort and two others, although no difference in birth mode is detected. A previous study has shown that bacterial OTU’s (operational taxonomic units) identified in the same infants could not discriminate between birth mode at 12 months of age. Therefore, our results indicate that vertical transmission of viral communities from mother to child may play a role in shaping the early life microbiome, and that birth mode should be considered when studying the early life gut virome.

Mode of birth in twins: data and reflections

Our primary objective was to compare neonatal and maternal outcomes in women with twin pregnancies, beyond 32 weeks, having a planned vaginal birth or a planned caesarean section (CS). This was a retrospective cohort study from a single tertiary centre over nine years. 534 sets of twins ≥32 + 0 weeks of gestation were included. 401 sets were planned vaginally and 133 sets were planned by CS. We compared a composite adverse perinatal outcome (perinatal mortality or serious neonatal morbidity; five minute APGAR score ≤4, neurological abnormality and need for intubation) and a composite maternal adverse outcome (major haemorrhage, trauma or infection) between the groups. There were no significant differences. Given the similarity of these results with several other larger studies of twin birth, we sought to look at reasons why there is still a rising rate of CS for twin births. We further make suggestions for keeping this rate to a sensible minimum. Impact statement What is already known on this subject? The largest randomised controlled study comparing planned vaginal birth with planned CSs for lower risk twins between 32 and 39 weeks of gestation, showed no added safety from planned CS. However, in most of the Western countries this conclusion has failed to increase the number of planned vaginal births for lower risk twins. What do the results of this study add? This observational study from a single tertiary centre provides external validation of the twin trial results in a practical day-to-day setting. It also provides insights as to how planned vaginal birth can be developed and maintained, with a key focus on safety and maternal participation in decision making. It does focus on consent and providing accurate data. What are the implications of these findings for clinical practice and/or further research? There are good grounds to encourage vaginal birth for low-risk twin pregnancies. The trend of rising caesarean rates in low-risk twin pregnancies worldwide will erode important skills for the conduct of vaginal births without any clear benefit for mothers or babies. The current situation demands careful thought about implementing innovative training opportunities for younger obstetricians. Finally, we need intelligent responses to many non-evidence-based factors which can drive clinical practice.