Respiratory transition in infants delivered by cesarean section

Transferring an extremely premature infant to an extra-uterine life support system: a prospective view on the obstetric procedure

To improve care for extremely premature infants, the development of an extrauterine environment for newborn development is being researched, known as Artificial Placenta and Artificial Womb (APAW) technology. APAW facilitates extended development in a liquid-filled incubator with oxygen and nutrient supply through an oxygenator connected to the umbilical vessels. This setup is intended to provide the optimal environment for further development, allowing further lung maturation by delaying gas exposure to oxygen. This innovative treatment necessitates interventions in obstetric procedures to transfer an infant from the native to an artificial womb, while preventing fetal-to-neonatal transition. In this narrative review we analyze relevant fetal physiology literature, provide an overview of insights from APAW studies, and identify considerations for the obstetric procedure from the native uterus to an APAW system. Lastly, this review provides suggestions to improve sterility, fetal and maternal well-being, and the prevention of neonatal transition.

Long term respiratory morbidity of cesarean-delivered second twin compared to their vaginally-delivered sibling: A retrospective population-based cohort study

BACKGROUND

Offspring born via cesarean delivery (CD) may be more prone to develope long-term respiratory diseases, compared to those delivered vaginally (VD). In this study, we compared the rates of respiratory diseases between first twins VD and second twins delivered via CD.

METHODS

This was a retrospective database study. All twin deliveries encompassed at the Soroka University Medical Center, a large tertiary hospital in southern Israel, between 1991 and 2020, in which the first twin was VD and the second via CD were included. Respiratory diseases included respiratory tract diseases such as bronchiolitis and bronchial asthma. The cumulative incidence of respiratory diseases was compared between the twins using Kaplan-Meier survival analysis and multivariable Cox models to adjust for confounding variables.

RESULTS

A total of 395,408 deliveries occurred during the study period, with 13,402 (3.4%) of all deliveries being twins. Of these, 184 (1.4%) were first twins VD and second twins delivered via CD. The second CD twin was more likely to have a non-reassuring fetal heart rate pattern and an Apgar score less than 7 at 5 min. No other differences were found between the siblings. The incidence of long-term respiratory diseases was not statistically different between the CD and VD siblings (7.6% vs. 9.4%, respectively; OR = 0.54; 95% CI: 0.23-1.26). Similarly, the cumulative incidence of respiratory diseases was not statistically different (Kaplan-Meier, log-rank, p = .59), and in the multivariable analysis which adjusted for birthweight and fetal distress during delivery (adjusted hazard ratio = 1.06; 95% CI: 0.43-26.25).

CONCLUSIONS

While the immediate outcomes for the CD twin were slightly worse compared to the VD twin, there was no difference in long-term respiratory diseases between the siblings.

Association between Low Cord Serum Cortisol Level and Transient Tachypnea of the Newborn in Late Preterm and Term Neonates Delivered by Elective Cesarean Section

OBJECTIVE

Transient tachypnea of the newborn (TTN), a common neonatal respiratory morbidity, is associated with failure of adequate clearance of fetal lung fluid. Glucocorticoids have an important role in lung maturity and the mechanisms of lung fluid clearance. The aim of this study is to assess the association between umbilical cord cortisol levels and transient TTN in late preterm and term neonates delivered by elective cesarean section (CS).

STUDY DESIGN

A case-control study of 37 newborns diagnosed with TTN (cases) was compared with 40 healthy newborns (controls). All infants were delivered by elective CS without labor. Umbilical cord cortisol levels were measured using enzyme-linked immunosorbent assay.

RESULTS

Mean cord cortisol levels were significantly lower in cases than controls (131.36 vs. 233.32 nmol/L, p = 0.0001; odds ratio [OR] = 3.7; 95% confidence interval [CI]: 1.40-9.53), respectively. Cord serum cortisol correlated inversely with the duration of tachypnea and the respiratory rate (r =  - 0.678 and -0.535, respectively).

CONCLUSION

Umbilical cord cortisol levels are significantly lower in newborns with transient TTN, and lower cortisol levels are associated with an increased respiratory rate and longer duration of admission. Antenatal glucocorticoids can be recommended for late preterm delivered by CS.

KEY POINTS

· Umbilical cord cortisol levels were lower in late preterm infants with TTN.. · Late preterm newborn with severe TTN and NICU hospitalization have lower cord cortisol levels.. · Antenatal glucocorticoids can be recommended for late preterm delivered by CS..

Antenatal Corticosteroids Decrease the Risk of Composite Neonatal Respiratory Morbidity in Planned Early Term Cesarean Deliveries

OBJECTIVE

While administration of antenatal corticosteroids prior to term elective cesarean deliveries has been shown in international randomized controlled trials to decrease the rates of respiratory distress syndrome and transient tachypnea of the newborn, this is not a standard practice in the United States. We aim to determine if the administration of antenatal corticosteroids for fetal lung maturation within 1 week of scheduled early term cesarean delivery resulted in decreased composite respiratory morbidity.

STUDY DESIGN

Historical cohort study including women who underwent scheduled early term cesarean delivery of a singleton, non-anomalous neonate at Mount Sinai Hospital between May 2015 and August 2019, comparing those who completed a course of antenatal corticosteroids within 1 week of delivery to those who did not. The primary outcome was composite respiratory morbidity defined as respiratory distress syndrome, transient tachypnea of the newborn, and neonatal intensive care unit admission for respiratory morbidity. Maternal and neonatal characteristics were compared between groups using t-tests or Wilcoxon-Rank Sum tests for continuous measures and Chi-square or Fisher's exact tests for categorical measures, as appropriate. The outcomes were assessed using logistic regression.

RESULTS

History of preterm birth was significantly higher in those who received antenatal corticosteroids compared with those who did not (24.0 vs. 10.9%, p = 0.01). Neonates who were not exposed to antenatal corticosteroids were more likely to experience the composite respiratory morbidity compared with those who were exposed (RR 4.1, 95% CI 1.2-13.7; p = 0.02). Between 37 and 38 weeks, neonates who did not receive steroids were at increased risk of composite respiratory morbidity (RR 11.7, 95% CI 1.5-89.0, p < 0.01), however, there was no difference for those born between 38 and 39 weeks.

CONCLUSION

Betamethasone course administered prior to planned early term cesarean delivery was associated with a statistically significant reduction in the neonatal composite respiratory morbidity compared with routine management.

KEY POINTS

· Steroids administered prior to scheduled cesarean lead to decreased neonatal respiratory morbidity.. · Steroid administration was not associated with increased adverse neonatal outcomes.. · Steroid administration was most beneficial between 37 and 38 weeks..

Birth, love, and fear: Physiological networks from pregnancy to parenthood

Pregnancy and childbirth are among the most dramatic physiological and emotional transformations of a lifetime. Despite their central importance to human survival, many gaps remain in our understanding of the temporal progression of and mechanisms underlying the transition to new parenthood. The goal of this paper is to outline the physiological and emotional development of the maternal-infant dyad from late pregnancy to the postpartum period, and to provide a framework to investigate this development using non-invasive timeseries. We focus on the interaction among neuroendocrine, emotional, and autonomic outputs in the context of late pregnancy, parturition, and post-partum. We then propose that coupled dynamics in these outputs can be leveraged to map both physiologic and pathologic pregnancy, parturition, and parenthood. This approach could address gaps in our knowledge and enable early detection or prediction of problems, with both personalized depth and broad population scale.

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Giving birth and caring for offspring are dynamic processes that can instill both love and fear.

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Maternal physiology continuously integrates fetal, social, and environmental cues.

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The result is coupled change in hormonal, autonomic nervous, and emotional output.

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Coupling may allow internal state to be assessed from peripheral autonomic markers.

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Such markers may identify healthy or pathologic pregnancy, parturition, and parenting, and enable creation of real-world tools.

Increased airway liquid volumes at birth impairs cardiorespiratory function in preterm and near-term lambs

Respiratory distress is relatively common in infants born at or near-term, particularly in infants delivered following elective cesarean section. The pathophysiology underlying respiratory distress at term has largely been explained by a failure to clear airway liquid, but recent physiological evidence has indicated that it results from elevated airway liquid at the onset of air-breathing. We have investigated the effect of elevated airway liquid volumes at birth on cardiorespiratory function in preterm and near-term lambs. Preterm (130 ± 0 days gestation, term ~147 days gestation; n=13) and near-term (139 ± 1 days gestation; n=13) lambs were instrumented (to measure blood pressure, blood flow and blood gas status) and at delivery airway liquid volumes were adjusted to mimic levels expected following vaginal delivery (Controls; ~7mL/kg) or elective caesarean section with no labour (elevated liquid; EL; 37mL/kg). Lambs were delivered, mechanically ventilated and monitored for blood gas status, oxygenation, ventilator requirements, blood flows (carotid artery and pulmonary artery) and blood pressure during the first few hours of life. Preterm and near-term EL lambs had poorer gas exchange and required greater ventilatory support to maintain adequate oxygenation. Pulmonary blood flow was reduced and carotid artery blood flow, mean arterial blood pressure and heart rate were reduced in EL near-term but not preterm lambs. These data provide further evidence that greater airway liquid volumes at birth adversely effects newborn cardiorespiratory function, with the effects being greater in near-term newborns.

Time Interval From Early-Term Antenatal Corticosteroids Administration to Delivery and the Impact on Neonatal Outcomes

OBJECTIVES

To determine the association between the time interval from antenatal corticosteroids administration to delivery and neonatal complications in diabetic mothers undergoing early term (37+0 to 38+6 weeks) scheduled cesarean section (ETSCS).

STUDY DESIGN

A retrospective cohort study of women with any form of diabetes in pregnancy undergoing ETSCS was included. Cases were stratified into the following groups based on the time interval from the first dose of corticosteroids administration to delivery: <2, 2-7, and >7 days. Women undergoing ETSCS, who did not receive corticosteroids were included as controls. We assessed the association between the time interval and neonatal outcomes in a multivariate regression model that controlled for potential confounders. Primary outcomes were the incidence of respiratory distress syndrome (RDS)/transient tachypnea of the newborn (TTN) and neonatal hypoglycemia.

RESULTS

The study cohort comprised 1,165 neonates. Of those, 159 (13.6%) were delivered within 2 days of maternal corticosteroids administration, 131 (11.2%) were delivered within 2-7 days after maternal corticosteroids administration, and 137 (11.8%) delivered more than 7 days after maternal corticosteroids administration. The remaining 738 (63.3%) were not exposed to corticosteroids. Multivariate analysis demonstrated that delivery within any time of antenatal corticosteroids administration was not associated with decreased risks of RDS/TTN. The risk of neonatal hypoglycemia was highest in the delivery of <2 days group (adjusted odds ratio [aOR]: 2.684, 95% confidence interval [CI]: 1.647-4.374 for control group; aOR: 2.827, 95% CI: 1.250-6.392 for delivery 2-7 days group; aOR:2.975, 95% CI: 1.265-6.996 for delivery >7 days group).

CONCLUSIONS

Corticosteroids treatment for diabetic mothers undergoing ETSCS was not associated with beneficial neonatal respiratory outcomes. In addition, delivery, <2 days after antenatal corticosteroids administration was associated with an increased risk of neonatal hypoglycemia.

Fluid status changes during the transition in infants of diabetic mothers

In animal and human neonates, expansion of the extracellular fluid volume is associated with "wet" lung and poor respiratory outcomes. To define fluid status changes during the transition from fetal to neonatal life in infants of diabetic mothers (IDM), we conducted a single-centre (Policlinico Abano Terme, Abano Terme, Italy) study of 66 IDM and a 1:2 matched control group from January 1 to September 30, 2020. Fluid status changes were assessed by computing Δ Hct from umbilical cord blood at birth and capillary heel Hct at 48 h, accounting for body weight decrease. IDM presented with significantly lower cord blood Hct levels in comparison to controls (47.33 ± 4.52 vs 50.03 ± 3.51%, p < 0.001), mainly if delivered by elective cesarean Sect. (45.01 ± 3.77 vs 48.43 ± 3.50%, p = 0.001). Hct levels at 48 h were comparable (55.18 ± 5.42 vs 54.62 ± 7.41%, p = 0.703), concurrently with similar body weight decrease (- 217.21 ± 113.34 vs - 217.51 ± 67.28 g, p = 0.614). This supports significantly higher ∆ Hct in IDM (5.13 ± 5.24 vs 7.29 ± 6.48, p < 0.01) and extra circulating fluid loss of 2-3%.Conclusion: Gestational diabetes is associated with an excess of circulating fluids during the transition from fetal to neonatal life, challenging the current assumption that is per se at risk of wet lung. What is Known: • In neonates, evidence suggests that expansion of the extracellular fluid volume prior to the postnatal diuresis is associated with poor respiratory outcomes. What is New: • Gestational diabetes is associated with an excess of circulating fluids during the transition from fetal to neonatal life, challenging the current assumption that is per se at risk of wet lung.

Gravity-induced loss of aeration and atelectasis development in the preterm lung: a serial sonographic assessment

OBJECTIVE

To assess the impact of gravity and time on the changes in the distribution patterns of loss of aeration and atelectasis development in very preterm infants.

STUDY DESIGN

Preterm infants less than 32 weeks gestation were included in this prospective, observational study. Infants were assessed via serial lung ultrasound (LUS) score in four lung zones, performed on days 7, 14, 21, and 28 after birth.

RESULT

Eighty-eight patients were enrolled. There was a significant main effect of gravity (P < 0.001) and time (P = 0.01) on the LUS score between gravity-dependent lungs and non-dependent lungs. Moreover, there was a significant main effect of gravity (P = 0.003) on atelectasis development between the lungs.

CONCLUSION

Gravity and time have an impact on the changes in the distribution patterns of gravity-induced lung injuries in preterm infants.

A critical appraisal of tools for delivery room assessment of the newborn infant

Assessment of an infant's condition in the delivery room represents a prerequisite to adequately initiate medical support. In her seminal paper, Virginia Apgar described five parameters to be used for such an assessment. However, since that time maternal and neonatal care has changed; interventions were improved and infants are even more premature. Nevertheless, the Apgar score is assigned to infants worldwide but there are concerns about low interobserver reliability, especially in preterm infants. Also, resuscitative interventions may preclude the interpretation of the score, which is of concern when used as an outcome parameter in delivery room intervention studies. Within the context of these changes, we performed a critical appraisal on how to assess postnatal condition of the newborn including the clinical parameters of the Apgar score, as well as selected additional parameters and a proposed new scoring system. The development of a new scoring system that guide clinicians in assessing infants and help to decide how to support postnatal adaptation is discussed. IMPACT: This critical paper discusses the reliability of the Apgar score, as well as additional parameters, in order to improve assessment of a newborn's postnatal condition. A revised neonatal scoring system should account for infant maturity and the interventions administered. Delivery room assessment should be directed toward determining how much medical support is needed and how the infant responds to these interventions.

Antenatal corticosteroids prior to planned caesarean at term for improving neonatal outcomes

BACKGROUND

Infants born at term by elective caesarean section are more likely to develop respiratory morbidity than infants born vaginally. Prophylactic corticosteroids in singleton preterm pregnancies accelerate lung maturation and reduce the incidence of respiratory complications. It is unclear whether administration at term gestations, prior to caesarean section, improves the respiratory outcomes for these babies without causing any unnecessary morbidity to the mother or the infant.

OBJECTIVES

The objective of this review was to assess the effect of prophylactic corticosteroid administration before elective caesarean section at term, as compared to usual care (which could be placebo or no treatment), on fetal, neonatal and maternal morbidity. We also assessed the impact of the treatment on the child in later life.

SEARCH METHODS

For this update, we searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov (20 January 2021) and reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials comparing prophylactic antenatal corticosteroid administration (betamethasone or dexamethasone) with placebo or with no treatment, given before elective caesarean section at term (at or after 37 weeks of gestation). Quasi-randomised and cluster-randomised controlled trials were also eligible for inclusion.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane Pregnancy and Childbirth methods for data collection and analysis. Two review authors independently assessed trials for inclusion, assessed risk of bias, evaluated trustworthiness (based on predefined criteria developed by Cochrane Pregnancy and Childbirth), extracted data and checked them for accuracy and assessed the certainty of the evidence using the GRADE approach. Our primary outcomes were respiratory distress syndrome (RDS), transient tachypnoea of the neonate (TTN), admission to neonatal special care for respiratory morbidity and need for mechanical ventilation. We planned to perform subgroup analyses for the primary outcomes according to gestational age at randomisation and type of corticosteroid (betamethasone or dexamethasone). We also planned to perform sensitivity analysis, including only studies at low risk of bias.

MAIN RESULTS

We included one trial in which participants were randomised to receive either betamethasone or usual care. The trial included 942 women and 942 neonates recruited from 10 UK hospitals between 1995 and 2002. This review includes only trials that met predefined criteria for trustworthiness. We removed three trials from the analysis that were included in the previous version of this review. The risk of bias was low for random sequence generation, allocation concealment and incomplete outcome data. The risk of bias for selective outcome reporting was unclear because there was no published trial protocol, and therefore it is unclear whether all the planned outcomes were reported in full. Due to a lack of blinding we judged there to be high risk of performance bias and detection bias. We downgraded the certainty of the evidence because of concerns about risk of bias and because of imprecision due to low event rates and wide 95% confidence intervals (CIs), which are consistent with possible benefit and possible harm Compared with usual care, it is uncertain if antenatal corticosteroids reduce the risk of RDS (relative risk (RR) 0.34 95% CI 0.07 to 1.65; 1 study; 942 infants) or TTN (RR 0.52, 95% CI 0.25 to 1.11; 1 study; 938 infants) because the certainty of evidence is low and the 95% CIs are consistent with possible benefit and possible harm. Antenatal corticosteroids probably reduce the risk of admission to neonatal special care for respiratory complications, compared with usual care (RR 0.45, 95% CI 0.22 to 0.90; 1 study; 942 infants; moderate-certainty evidence). The proportion of infants admitted to neonatal special care for respiratory morbidity after treatment with antenatal corticosteroids was 2.3% compared with 5.1% in the usual care group. It is uncertain if antenatal steroids have any effect on the risk of needing mechanical ventilation, compared with usual care (RR 4.07, 95% CI 0.46 to 36.27; 1 study; 942 infants; very low-certainty evidence). The effect of antenatal corticosteroids on the maternal development of postpartum infection/pyrexia in the first 72 hours is unclear due to the very low certainty of the evidence; one study (942 women) reported zero cases. The included studies did not report any data for neonatal hypoglycaemia or maternal mortality/severe mortality.

AUTHORS' CONCLUSIONS

Evidence from one randomised controlled trial suggests that prophylactic corticosteroids before elective caesarean section at term probably reduces admission to the neonatal intensive care unit for respiratory morbidity. It is uncertain if administration of antenatal corticosteroids reduces the rates of respiratory distress syndrome (RDS) or transient tachypnoea of the neonate (TTN). The overall certainty of the evidence for the primary outcomes was found to be low or very low, apart from the outcome of admission to neonatal special care (all levels) for respiratory morbidity, for which the evidence was of moderate certainty. Therefore, there is currently insufficient data to draw any firm conclusions.  More evidence is needed to investigate the effect of prophylactic antenatal corticosteroids on the incidence of recognised respiratory morbidity such as RDS. Any future trials should assess the balance between respiratory benefit and potential immediate adverse effects (e.g. hypoglycaemia) and long-term adverse effects (e.g. academic performance) for the infant. There is very limited information on maternal health outcomes to provide any assurances that corticosteroids do not pose any increased risk of harm to the mother.  Further research should consider investigating the effectiveness of antenatal steroids at different gestational ages prior to caesarean section. There are nine potentially eligible studies that are currently ongoing and could be included in future updates of this review.

Type 2 diabetes and neonatal hypoglycemia: role of route of delivery and insulin infusion

OBJECTIVE

To compare the rate of neonatal hypoglycemia among newborns delivered by individuals with Type 2 diabetes mellitus (T2DM) in two clinical scenarios: who attempted vaginal delivery vs. had a planned cesarean delivery (CD); who had intrapartum insulin infusion vs. who did not.

METHODS

This was a retrospective cohort study of individuals with insulin-treated T2DM who had non-anomalous singleton pregnancy and delivered at a single tertiary center (March 2012 and May 2018). Individuals with chronic renal failure, proliferative retinopathy, or major congenital anomalies were excluded. The primary outcome was neonatal hypoglycemia (blood glucose < 40 mg/dl <24 h of age or < 50 mg/dl >24 h of age). Secondary outcomes included neonatal outcomes. Multivariable Poisson regression models with robust error variance were used to examine the association between groups and the primary outcome. Adjusted relative risk (aRR) and 95% confidence intervals (CI) were calculated.

RESULTS

Of 233 individuals with T2DM, 215 (92.2%) met the inclusion criteria, of whom 95 (44%) attempted vaginal delivery and 120 (56%) had a planned CD. Individuals who labored had a higher gestational age at delivery (36.6 vs. 35.8 weeks, p = .005), and higher blood glucose levels upon admission (125 vs 103, p < .001) compared to those with a planned CD. After adjustment for potential confounders, there was no difference in risk of neonatal hypoglycemia between the groups (41.2 vs 44.1%, aRR 1.05, 95% CI = 0.75-1.45). Among those who attempted vaginal delivery, 34 (35.8%) required insulin infusion. There was no difference in the risk of neonatal hypoglycemia (aRR = 0.79, 95% CI = 0.45-1.37) between newborns delivered by individuals who required insulin infusion and those who did not.

CONCLUSION

Over 40% of newborns delivered by individuals with insulin-dependent T2DM had hypoglycemia; however, there was no significant difference in the risk of hypoglycemia, irrespective of the route of delivery and the use of insulin infusion.

Tidal breath in healthy term newborns: An analysis from the 2nd to the 30th days of life

BACKGROUND

Few data are available concerning normative lung function parameters measured in unsedated neonates.

AIM

To evaluate lung function changes in neonates.

METHODS

In this prospective cohort study, tidal breath parameters were measured using the MasterScreen PAED system and standardized protocols. Measurements were performed on 60 (30 male) term, healthy, unsedated neonates on the postnatal 2nd and 30th days.

RESULTS

Expiratory time (TE; p < .001; Cohen's d = 0.561), exhaled volume to peak tidal expiratory flow (VPTEF; p < .001; Cohen's d = 0.789), minute ventilation (p < .001; Cohen's d = 0.926), tidal volume (VT; p < .001; Cohen's d = 1.835), expiratory flow when 75%, 50%, and 25% of tidal volume remaining in the lungs (TEF75 [p < .001; Cohen's d = 1.070], TEF50 [p < .001; Cohen's d = 0.824], TEF25 [p < .001; Cohen's d = 0.568]), and inspiratory time (Ti; p < .001; Cohen's d = 0.654) were higher on Day 30 compared to Day 2, while time to reach peak tidal expiratory flow to total expiratory time (TPTEF/TE; p = .006; Cohen's d = 0.371), the volume until peak tidal expiratory flow to total expiratory volume (VPTEF/VE; p = .001; Cohen's d = 0.447), and respiration rate (RR; p = .001; Cohen's d = 0.432) were lower, and Ti/TE was unchanged. Positive correlation was observed between length and VT (r = .347; p = .008) on Day 2 and (r = .338; p = .008) on Day 30.

CONCLUSIONS

The present study reveals the physiological changes occurring in lung functions in healthy term neonates during the neonatal period.

Effect of delivery mode on neonate auditory brainstem responses to air- and bone-conducted stimuli

OBJECTIVES

The object of this study was to examine if caesarean section delivered neonates have different middle ear function relative to neonates with vaginal delivery.

METHODS

Auditory brainstem responses (ABRs) were examined in caesarean section delivered (n = 23) and vaginally delivered (n = 29) neonates. ABRs were also evoked with air- and bone-conducted stimuli (i.e., clicks and CE-Chirps) and presented at a screening intensity level (i.e., 30 dB nHL). Wave V latencies and amplitudes were examined as a function of mode of delivery and stimuli.

RESULTS

Statistically significant longer wave V latencies evoked with air-conducted stimuli were seen in caesarean section delivered neonates (p = .042). There was no statistically significant difference in wave V latencies with bone-conducted stimuli among the two groups of neonates (p = .42). There were no significant differences in wave V amplitude between neonates with caesarean section and vaginal delivery for air-conducted (p = .42) stimuli. Wave V amplitudes were not significantly different as a function of mode of delivery with CE-Chirp stimulus (p = .41). Wave V amplitudes were significantly larger for the caesarean section delivered neonates with the bone-conducted click stimulus (p = .036).

CONCLUSIONS

The ABR wave V latency disparity with air- and bone-conducted stimuli support the notion that differences in middle ear function exist between the two groups of newborns. It was speculated that delayed fluid resorption in the middle ear exists in neonates with caesarean section delivery compared to those with vaginal delivery.

Procalcitonin Level at 24 Hours of Age May be Predictive for Transient Tachypnea of the Newborn

Objective It is an important problem to differentiate transient tachypnea of the newborn (TTN) from bacterial pneumonia or other conditions in patients admitted to Neonatal Intensive Care Unit. The aim of this study was to evaluate the predictive value of procalcitonin (PCT) for TTN.

Methods A total of 52 infants were contained in the study. The patients were divided into three groups. Group 1 consisted of patients with pronounced grunting at more than 2 hours postnatal age (n = 16). Group 2 consisted of patients whose grunt was reduced or gone at 2 hours postnatal age but in whom tachypnea persisted until 24 hours postnatal age (n = 18). Group 3 consisted of patients with minimal or no respiratory distress at 24 hours postnatal age (n = 18). In all groups, PCT concentrations were determined at birth and 24 hours postnatal age.

Results PCT concentrations at birth were significantly higher in Group 1 than other groups, but there was no difference between Groups 2 and 3. PCT concentrations at 24 hours postnatal age were significantly higher in Groups 1 and 2 than Group 3. No difference was found between Group 1 and Group 2 at 24 hours postnatal age. All PCT concentrations in Group 3 were significantly lower than other groups. PCT thresholds for the diagnosis of TTN were 0.44 ng/mL at birth (sensitivity 58%, specificity 50%) and 5.11 ng/mL at 24 hours postnatal age (sensitivity 79.4%, specificity 89.1%).

Conclusion Serial PCT measurements at birth and postnatal 24 hours may be helpful in differentiating between pneumonia and TTN. Further researches are needed to confirm this initial study.

Physiological Basis of Neonatal Aerodigestive Difficulties in Chronic Lung Disease

In the United States, preterm birth rates have steadily increased since 2014. Despite the recent advances in neonatal-perinatal care, more than 40% of very low-birth-weight infants develop chronic lung disease (CLD) and almost 25% have feeding difficulties resulting in delayed achievement of full oral feeds and longer hospital stay. Establishment of full oral feeds, a major challenge for preterm infants, becomes magnified among those on respiratory support and/or with CLD. The strategies to minimize aerodigestive disorders include supporting nonnutritive sucking, developing infant-directed feeding protocols, sensory oromotor stimulation, and early introduction of oral feeds.

Assessment of breath sounds at birth using digital stethoscope technology

Newborn transition is a phase of complex change involving lung fluid clearance and lung aeration. We aimed to use a digital stethoscope (DS) to assess the change in breath sound characteristics over the first 2 h of life and its relationship to mode of delivery. A commercially available DS was used to record breath sounds of term newborns at 1-min and 2-h post-delivery via normal vaginal delivery (NVD) or elective caesarean section (CS). Sound analysis was conducted, and two comparisons were carried out: change in frequency profiles over 2 h, and effect of delivery mode. There was a significant drop in the frequency profile of breath sounds from 1 min to 2 h with mean (SD) frequency decreasing from 333.74 (35.42) to 302.71 (47.19) Hz, p < 0.001, and proportion of power (SD) in the lowest frequency band increasing from 0.27 (0.11) to 0.37 (0.15), p < 0.001. At 1 min, NVD infants had slightly higher frequency than CS but no difference at 2 h.Conclusion: We were able to use DS technology in the transitioning infant to depict significant changes to breath sound characteristics over the first 2 h of life, reflecting the process of lung aeration.What is Known:• Lung fluid clearance and lung aeration are critical processes that facilitate respiration and mode of delivery can impact this• Digital stethoscopes offer enhanced auscultation and have been used in the paediatric population for the assessment of pulmonary and cardiac soundsWhat is New:• This is the first study to use digital stethoscope technology to assess breath sounds at birth• We describe a change in breath sound characteristics over the first 2 h of life and suggest a predictive utility of this analysis to predict the development of respiratory distress in newborns prior to the onset of symptoms.

Risk Factors for Neonatal Mortality in Preterm Newborns in The Extreme South of Brazil

Neonatal mortality still remains a complex challenge to be addressed. In Brazil, 60% of neonatal deaths occur among preterm infants with a gestational age of 32 weeks or less (≤32w). The aim of this study was to evaluate the factors involved in the high mortality rates among newborns with a gestational age ≤32w in a socioeconomically developed southern city in Brazil. Data on retrospective births and deaths (2000-2014) were analyzed from two official Brazilian national databases. The risk of neonatal death for all independent variables (mother's age and schooling, prenatal visits, birth hospital, delivery method, gestational age, and the newborn's sex, age, and birth year, gemelarity, congenital anomalies and birthplace) was assessed with a univariable and a multivariable model of Cox's semiparametric proportional hazards regression (p < 0.05). Data of 288,904 newborns were included, being 4,514 with a gestational age ≤32w. The proportion of these early newborns remained stable among all births, while the neonatal mortality rate for this group tended to decrease (p < 0.001). The adjusted risk was significantly for lower birthweight infants (mean 659.13 g) born from Caesarean (HR 0.58 [95% CI 0.47-0.71]), but it was significantly higher for heavier birth weight infants (mean 2,087.79) also born via Caesarean section (HR 3.71 [95% CI 1.5-9.15]). Newborns with lower weight seemed to benefit most from Cesarean deliveries. Effort towards reducing unacceptably high surgical deliveries must take into account cases that the operations may be lifesaving for mother and/or the baby.

Feasibility of combining two individualized lung recruitment maneuvers at birth for very low gestational age infants: a retrospective cohort study

Background

Lung recruitment at birth has been advocated as an effective method of improving the respiratory transition at birth. Sustained inflations (SI) and dynamic positive end-expiratory pressure (PEEP) were assessed in clinical and animal studies to define the optimal level. Our working hypothesis was that very low gestational age infants (VLGAI) < 32 weeks’ gestation require an individualized lung recruitment based on combining both manoeuvers.

Methods

Between 2014 and 2016, 91 and 72 inborn VLGAI, requiring a respiratory support beyond a continuous positive airway pressure (CPAP) = 5 cmH2O, were enrolled before and after introducing these manoeuvers based on progressive increase in SI up to 15 s, with simultaneous gradual increase in PEEP up to 15 cmH2O, according to the cardiorespiratory response. Retrospective comparisons of the incidence of mechanical ventilation (MV) < 72 h of life, short-term and before discharge morbidity were then performed.

Results

Among extremely low gestational age infants (ELGAI) < 29 weeks’ gestation, the following outcomes decreased significantly: intubation (90 to 55%) and surfactant administration (54 to 12%) in the delivery room, MV (92 to 71%) and its mean duration < 72 h of life (45 h to 13 h), administration of a 2nd dose of surfactant (35 to 12%) and postnatal corticosteroids (52 to 19%), and the rate of bronchopulmonary dysplasia (23 to 5%). Among VLGAI, all of these results were also significant. Neonatal mortality and morbidity were not different.

Conclusions

In our setting, combining two individualized lung recruitment maneuvers at birth was feasible and may be beneficial on short-term and before discharge pulmonary outcomes. A randomized controlled trial is needed to confirm these results.

The effect of delayed umbilical cord clamping on cord blood gas analysis in vaginal and caesarean-delivered term newborns without fetal distress: a prospective observational study

OBJECTIVE

To determine variations in cord blood gas (CBG) parameters after 3-minute delayed cord clamping (DCC) in vaginal deliveries (VDs) and caesarean deliveries (CDs) at term without fetal distress.

DESIGN

Prospective observational study.

SETTING

University hospital.

SAMPLE

CBG from 97 VDs and 124 CDs without fetal distress.

METHODS

Comparison of paired arterial-venous CBG parameters drawn at birth from the unclamped cord and after 3-minutes DCC for VDs and CDs.

MAIN OUTCOME MEASURES

Base excess, bicarbonate, haematocrit and haemoglobin from both arterial and venous cord blood, lactate, neonatal outcomes, partial pressure of oxygen (pO2 ), partial pressure of carbon dioxide (pCO2 ), pH, and postpartum haemorrhage.

RESULTS

Arterial cord blood pH, bicarbonate ( HCO 3 - , mmol/l), and base excess (BE, mmol/l) decreased significantly after 3-minute DCC both in VDs (pH = 7.23 versus 7.27; P < 0.001; HCO 3 -  = 23.3 versus 24.3; P = 0.004; BE = -5.1 versus -2.9; P < 0.001) and CDs (pH = 7.28 versus 7.34; P < 0.001; HCO 3 -  = 26.2 versus 27.2; P < 0.001; BE = -1.5 versus 0.7; P < 0.001). After 3-minute DCC, pCO2 increased in CDs only (57 versus 51; P < 0.001), whereas lactate increased more in CDs compared with VDs (lactate, +1.1 [0.9, 1.45] versus +0.5 [-0.65, 2.35]; P = 0.01). Postpartum maternal haemorrhage, neonatal maximum bilirubin concentration, and need for phototherapy were similar between the two groups. Newborns born by CD more frequently required postnatal clinical monitoring or admission to a neonatal intensive care unit.

CONCLUSIONS

After 3-minute DCC, the acid-base status shifted towards mixed acidosis in CDs and prevalent metabolic acidosis in VDs. CDs were associated with a more pronounced increase in arterial lactate, compared with VDs.

TWEETABLE ABSTRACT

By 3-minute DCC, acid-base status shifts towards mixed and metabolic acidosis in caesarean and vaginal delivery, respectively.

Transient Tachypnea of Newborns Is Associated With Maternal Spinal Hypotension During Elective Cesarean Delivery: A Retrospective Cohort Study

BACKGROUND

The risk for transient tachypnea of newborns, a common cause of respiratory distress in the neonatal period, is 2- to 6-fold higher during elective cesarean delivery compared to vaginal delivery. Here, we evaluated the association between transient tachypnea of newborns and the degree and duration of predelivery maternal hypotension during spinal anesthesia for elective cesarean delivery.

METHODS

Demographic data, details of anesthetic management, blood pressure measurements, and vasopressor requirement preceding delivery were compared between transient tachypnea newborns (n = 30) and healthy neonates (n = 151) with normal respiratory function born via elective cesarean delivery between July 2015 and February 2016. The degree and duration of hypotension were assessed using area under the curve for systolic blood pressure (SBP) ≤90 mm Hg and area under the curve for mean arterial pressure ≤65 mm Hg. After adjusting for confounders, multivariable logistic regression was used to evaluate the association between area under the curve for SBP and transient tachypnea of newborns.

RESULTS

The median area under the curve for SBP was higher in cases of transient tachypnea of newborns (0.94; interquartile range, 0-28.7 mm Hg*min) compared to healthy controls (0; interquartile range, 0-3.30 mm Hg*min; P = .001). Similarly, median area under the curve for mean arterial pressure was also higher in cases of transient tachypnea of newborns (0; interquartile range, 0-18.6 mm Hg*min) compared to controls (0; interquartile range, 0-1.1 mm Hg*min; P = .01). Mothers of transient tachypnea newborns received significantly higher amounts of phenylephrine and ephedrine compared to controls (P = .001 and 0.01, respectively). Hence, the total vasopressor dose given to mothers in the transient tachypnea of newborn group was much higher than for the control group (P = .001). In the multivariable logistic regression, area under the curve for SBP was significantly associated with transient tachypnea of newborns (odds ratio, 1.02; 95% CI, 1.01-1.04, P = .005) after adjusting for gravidity and the type of anesthetic (spinal versus combined spinal epidural).

CONCLUSIONS

Our results suggest that the degree and duration of maternal SBP <90 mm Hg after neuraxial anesthesia during elective cesarean delivery are associated with transient tachypnea of newborns. Future prospective studies should further explore the effects of maternal hypotension, its prevention, and treatment for transient tachypnea of newborns.

Elective Cesarean Section on Term Pregnancies Has a High Risk for Neonatal Respiratory Morbidity in Developed Countries: A Systematic Review and Meta-Analysis

Background: Cesarean section (CS) is one of the most recurrently carried out surgical procedures in modern obstetrics. Worldwide, about 18.5 million CSs are conducted annually. Of this, 21-33% are performed in middle-and high-income countries. The effectiveness of the CS in preventing maternal and prenatal mortality and morbidity is medically justifiable. However, cesarean delivery without demanding obstetrical indications, by mere maternal request, may expose the child to several risks over benefits. Therefore, we aim to compare spontaneous vaginal delivery (vaginal delivery other than operative vaginal deliveries) and elective CS (CS before the onset of labor, but not including emergency CS) in decreasing the risk of neonatal respiratory morbidity. Objective: To compare the risk of neonatal respiratory morbidity in ECS and spontaneous vaginal delivery. Methods: A literature search was performed through visiting an electronic database (MEDLINE, PubMed, EMBASE, and CINAHL) and gray literature sources, including Google and Google Scholar, from January 2000 to May 2018. Original observational studies that reported the risk of neonatal respiratory morbidity in relation to mode of delivery conducted in the English language were identified and screened. Joanna Briggs Institute's quality assessment tool for observational studies was used to critically appraise the methodological quality of studies. Synthesis of individual studies was conducted using the Review Manager Software version 5.3 for Windows. Heterogeneity among studies was explored using the Cochran's Q-test and the I ² statistics. Pooled effect sizes in relative risk ratios with 95% confidence intervals were calculated. The flow of the study was prepared according to the Meta-analysis of Observational Studies in Epidemiology (MOOSE) checklist. Results: Sixteen studies were reviewed. A total of 327,272 neonates born by vaginal delivery and 55,246 born by ECS were included in this study. The risk of neonatal respiratory morbidity was increased by 95% in neonates delivered by ECS (RR = 1.95; 95% CI: 1.40-2.73) as compared with neonates born by spontaneous vaginal delivery. Conclusion: This study investigated the effect of mode of delivery on the respiratory morbidity without considering other risks and found that the ECS has a high risk of developing neonatal respiratory morbidities when compared to spontaneous vaginal delivery. So, we recommend discouraging unnecessary CS. registration: CRD42018104905.

Issues in cardiopulmonary transition at birth

The transition from fetal to newborn life involves a complex series of physiological events that commences with lung aeration, which is thought to involve 3 mechanisms. Two mechanisms occur during labour, Na⁺ reabsorption and fetal postural changes, and one occurs after birth due to pressure gradients generated by inspiration. However, only one of these mechanisms, fetal postural changes, involves the loss of liquid from the respiratory system. Both other mechanisms involve liquid being reabsorbed from the airways into lung tissue. While this stimulates an increase in pulmonary blood flow (PBF), in large quantities this liquid can adversely affect postnatal respiratory function. The increase in PBF (i) facilitates the onset of pulmonary gas exchange and (ii) allows pulmonary venous return to take over the role of providing preload for the left ventricle, a role played by umbilical venous return during fetal life. Thus, aerating the lung and increasing PBF before umbilical cord clamping (known as physiological based cord clamping), can avoid the loss of preload and reduction in cardiac output that normally accompanies immediate cord clamping.

Cesarean section and the risk of neonatal respiratory distress syndrome: a meta-analysis

PURPOSE

To explore the association between cesarean section (CS) and the risk of neonatal respiratory distress syndrome (RDS).

METHODS

We searched PubMed, Web of Science, and ClinicalTrials.gov database for studies related to the association between CS and the risk of neonatal RDS up to 25 August 2018. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were estimated using a random-effects model (REM).

RESULTS

A total of 26 studies from 25 available articles were included in this meta-analysis. For the association between CS and the risk of neonatal RDS, the pooled OR was 1.76 (95% CI 1.48-2.09). The pooled OR of the risk of neonatal RDS was 2.38 (95% CI 1.89-2.99) for elective CS and 1.85 (95% CI 1.34-2.56) for emergency CS.

CONCLUSION

This meta-analysis suggested that CS, elective CS, and emergency CS were associated with an increased risk of neonatal RDS.

The place of antenatal corticosteroids in late preterm and early term births

Infants born in the late preterm period and via non-labour caesarean section in the early term period are at increased risk of respiratory morbidity when compared to their term-born counterparts. The morbidity in these infants is less frequent and severe than in early preterm infants. Antenatal corticosteroids reduce respiratory morbidity in these populations; however, the magnitude of the reduction appears to be small and predominantly in the self-limiting condition of transient tachypnoea of the neonate. The smaller benefit, along with possible harmful effects of corticosteroids, raises a question about the role of antenatal corticosteroids in this population. Special obstetric populations such as twin pregnancies and pregnancies complicated by diabetes and growth restriction are at increased risk of prematurity and more vulnerable to its complications. Nevertheless, there is limited evidence regarding the benefits of corticosteroids in these populations and potential concern regarding adverse effects. We recommend an individualised approach when administering corticosteroids at later gestations. In these specific obstetric populations, we do not currently recommend administering corticosteroids in the late preterm/early term periods until more evidence is available.

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.

Respiratory Compliance in Late Preterm Infants (340/7-346/7 Weeks) after Antenatal Steroid Therapy

OBJECTIVE

To compare respiratory compliance in late preterm infants (34^0/7-34^6/7 weeks) who received antenatal steroids vs matched late preterm infants who did not receive antenatal steroids.

STUDY DESIGN

This was a single-center prospective cohort study. Patients were matched for birth weight, gestational age, race, and sex. Respiratory compliance was the primary outcome measured with the single breath occlusion technique.

RESULTS

We studied 25 late preterm infants treated with antenatal steroids and 25 matched infants who did not receive antenatal steroids. The treated infants had a significantly increased respiratory compliance/kg (adjusted 95% CI 0.05, 0.49; P = .016) and fewer required continuous positive airway pressure (P = .007) or >24 hours of supplemental oxygen (P = .046). There was no difference in surfactant therapy.

CONCLUSIONS

Respiratory compliance was significantly increased in this cohort of late preterm infants born at 34^0/7-34^6/7 weeks who received antenatal steroids compared with matched infants who did not receive antenatal steroids. Although not randomized, these data provide physiologic support for the possible beneficial effects of antenatal steroids in late preterm infants.

Corticosteroids for preventing neonatal respiratory morbidity after elective caesarean section at term

BACKGROUND

Infants born at term by elective caesarean section are more likely to develop respiratory morbidity than infants born vaginally. Prophylactic corticosteroids in singleton preterm pregnancies accelerate lung maturation and reduce the incidence of respiratory complications.

OBJECTIVES

The objective of this review was to assess the effect of prophylactic corticosteroid administration before elective caesarean section at term, as compared to usual management without corticosteroids, in reducing neonatal respiratory morbidity and admission to special care with respiratory complications.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (14 June 2017), and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials comparing prophylactic antenatal corticosteroid administration (betamethasone or dexamethasone) with placebo or with no treatment, given before elective caesarean section at term (at or after 37 weeks of gestation).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. We assessed the quality of the evidence using the GRADE approach.

MAIN RESULTS

We included four trials (3956 women and 3893 neonates) at a moderate risk of bias, comparing prophylactic administration of betamethasone or dexamethasone versus placebo or usual treatment without steroids in term elective caesarean section. Women randomised to treatment group received either two intramuscular doses of betamethasone in the 48 hours before delivery, or intramuscular dexamethasone (two or four doses) prior to delivery (at 37 weeks' gestation or 48 hours before delivery), and were compared to the control group who received a saline placebo or treatment as usual.Prophylactic antenatal corticosteroid administration appeared to decrease the risk of respiratory distress syndrome (RDS) (risk ratio (RR) 0.48; 95% confidence interval (CI) 0.27 to 0.87; 4 studies; 3817 participants; low-quality evidence), transient tachypnoea of the neonate (TTN) (RR 0.43; 95% CI 0.29 to 0.65; 4 studies; 3821 participants; low-quality evidence), admission to the neonatal intensive care unit (NICU) for respiratory morbidity (RR 0.42; 95% CI 0.22 to 0.79; 3 studies; 3441 participants), and admission to neonatal special care (all levels) for respiratory complications (RR 0.45; 95% CI 0.22 to 0.90; 1 study; 942 participants; low-quality evidence). Administration of antenatal corticosteroids also appeared to reduce admission to neonatal special care (RR 0.62; 95% CI 0.43 to 0.89; 2 studies; 2169 participants) and neonatal intensive care (RR 0.14; 95% CI 0.03 to 0.61; 1 study; 452 participants) for any indication, compared to placebo or usual care. Finally, prophylactic antenatal corticosteroids also appeared to reduce the length of stay in NICU by 2.70 days (mean difference (MD) -2.70; 95% CI -2.76 to -2.64; 2 studies; 32 participants).No reduction was found in the need for mechanical ventilation (RR 0.67; 95% CI 0.27 to 1.68; 3 studies; 3441 participants; very-low quality), perinatal death (RR 0.67; 95% CI 0.11 to 4.10; 4 studies; 3893 participants) or neonatal sepsis (RR 1.00; 95% CI 0.06 to 15.95; 2 studies; 2214 participants) .There were no reported events of neonatal respiratory complications (other than RDS and tachypnoea of the newborn (TTN)), chronic lung disease, duration of mechanical ventilation or maternal postpartum infection, therefore results on these outcomes are non-estimable. The studies did not provide data on other pre-defined outcomes.The quality of evidence, as assessed using GRADE was low for the outcomes of RDS, TTN and admission to NICU for respiratory morbidity, indicating that the true effect could potentially be substantially different from our estimate of effect.

AUTHORS' CONCLUSIONS

The results from the four trials are promising, but more high-quality studies with larger sample sizes that are adequately powered to detect the effect of prophylactic antenatal corticosteroids on outcomes of respiratory morbidity are needed, given the potential of the current studies for bias. Consideration should be given to the balance between statistical significance and clinical significance, particularly in view of the low event rates of significant respiratory morbidity (RDS or admission to NICU for respiratory complications) in this population. In addition, further trials on the long-term outcomes of these infants are needed to identify any potential harms and complications of antenatal corticosteroid administration at term.

Association Between Mode of Delivery and Risk of Infection in Early Childhood: A Cohort Study

BACKGROUND

Infections are the leading cause of morbidity and mortality in children. Caesarean section as a potential risk factor for infection has recently gained interest. Delivery by caesarean section has increased greatly, with nonmedical reasons playing an increasing role. We aimed to analyze the association between mode of delivery and hospitalizations because of infection and symptoms of infection at home in early childhood.

METHODS

A cohort study, based on the Odense Child Cohort, following infants from gestation until a mean age of 3.5 years. Data on hospitalization because of infections were collected from the Danish National Patient Registry. Data on symptoms of infection at home were collected via a text message-based questionnaire.

RESULTS

A total of 1921 children were born by vaginal delivery, 283 by elective caesarean section and 227 by acute caesarean section. An adjusted regression model showed an incidence rate ratio for hospitalizations because of infection in children born by elective caesarean section compared with children born by vaginal delivery of 1.45 (95% confidence interval: 1.16-1.80; P = 0.001). The analyses on symptoms of infection at home found no associations between any symptom of infection and mode of delivery. Symptom-specific subanalyses showed contrasting results.

CONCLUSIONS

Mode of delivery showed a strong association to hospitalization because of infectious disease during early childhood. Overall, no association was present between rate of symptoms of infection at home and mode of delivery.

The physiology of neonatal resuscitation

PURPOSE OF REVIEW

As the infant's physiology changes dramatically after birth, modern neonatal resuscitation approaches should detect and be modified in response to these changes. This review describes the changes in respiratory physiology at birth and highlights approaches that can assist these changes.

RECENT FINDINGS

To better target assistance given to infants at birth, the changes in lung physiology have been classified into three phases. The first phase involves lung aeration. As little or no gas exchange can occur, assistance should focus on airway liquid clearance. During the second phase, as airway liquid resides in lung tissue, assistance should focus on minimizing the complications associated with lung edema. The third phase occurs whenever the liquid is cleared from the tissue and respiratory mechanics stabilize. Although more traditional approaches are most effective during this phase, this is not the case for the first two phases. Furthermore, the glottis actively adducts during apnea in newborns and so noninvasive respiratory support requires the infant to be breathing so that the glottis will open.

SUMMARY

The respiratory support provided to infants at birth should match the infant's changing physiology during transition, which requires a more sophisticated approach and equipment than current recommendations.

Factors relating caesarean section to persistent pulmonary hypertension of the newborn

BACKGROUND

Several studies have clearly demonstrated a significantly higher incidence of persistent pulmonary hypertension of the newborn (PPHN) in neonates delivered by caesarean section (CS) compared to those delivered vaginally. The pathophysiological factors underlying the link between CS and PPHN are still poorly understood. In this review, we describe the mechanisms that could explain the association between CS delivery and subsequent PPHN, as well as potential preventive measures.

DATA SOURCES

A literature search was conducted by electronic scanning of databases such as PubMed and Web of Science using the key words "persistent pulmonary hypertension of the newborn", "caesarean section", "iatrogenic prematurity", "oxidative stress", "late preterm", "labor" and "vasoactive agents".

RESULTS

Iatrogenic prematurity, higher rates of late preterm delivery and lack of physiological changes of labor play an important role in the association between CS and PPHN. CS delivery also results in limited endogenous pulmonary vasodilator synthesis and lower levels of protective anti-oxidants in the neonates. In addition, CS delivery exposes infants to a higher risk of respiratory distress syndrome and its concomitant increase in endothelin-1 levels, which might indirectly lead to a higher risk of developing PPHN. We believe that neonates delivered by CS are exposed to a combination of these pathophysiological events, culminating in an endpoint of respiratory distress, hypoxia, acidosis, and delayed transition and thereby increased risks of PPHN. The use of antenatal corticosteroids prior to elective CS in late preterm deliveries, promoting accurate informedconsent process, delaying elective CS to 39 weeks of gestation or beyond and antenatal maternal anti-oxidant supplementation could potentially mitigate the effects of CS delivery and minimize CS-related PPHN.

CONCLUSIONS

The link between CS delivery and PPHN is complex. In view of the rising rates of CS worldwide, there is an urgent need to further explore the mechanisms linking CS to PPHN and experimentally test therapeutic options in order to allow effective targeted interventions.

Relationship between thyroid hormone levels and transient tachypnea of the newborn in late-preterm, early-term, and term infants

PURPOSE

We aimed to investigate the association between thyroid hormone levels and transient tachypnea of the newborn (TTN) among late-preterm, early-term, and term infants admitted to neonatal intensive care unit (NICU).

MATERIALS AND METHOD

In the current retrospective study, neonates admitted to the NICU due to TTN were assigned to the TTN group (n = 404). Healthy neonates who were followed up in the well-baby nursery comprised the control group (n = 7335). Infants were grouped by gestational age into late-preterm (34-36⁶ weeks), early-term (37-38⁶ weeks), and term subgroups (39-41⁶ weeks). Serum levels of thyroid-stimulating hormone (TSH) and thyroxin (T₄) were determined from venipuncture samples taken at least 48 hours after birth. The relationship between thyroid hormone levels and the need for NICU admission for TTN was compared between groups.

RESULTS

Compared to control infants, term neonates with TTN had significantly higher TSH levels, whereas late-preterm and early-term neonates with TTN had significantly lower T₄ levels. Birth weight and mode of delivery had no effect on NICU admission for TTN.

CONCLUSIONS

Infants admitted to NICU due to TTN had significantly different thyroid hormone levels with differences depending on gestational age.

[Short-term clinical outcomes of neonates of secundiparous mothers: a single-center cohort study]

OBJECTIVE

To investigate the short-term clinical outcomes of neonates of secundiparous mothers, and to provide a reference for the clinical practice after the change in birth policy.

METHODS

A cohort study was performed for the parturients and their neonates born in Yongkang Maternal and Child Health Care Hospital in Zhejiang, China between June 2015 and April 2016. According to the parity of the mother, the neonates were divided into primiparous group and secundiparous group. The short-term clinical outcomes of neonates were compared between the two groups.

RESULTS

A total of 4 091 neonates who met the inclusion criteria were enrolled, and there were 2 023 neonates in the primiparous group and 2 068 in the secundiparous group. In the secundiparous group, most mothers (57.16%) were aged 26-34 years, and 16.49% were aged above 35 years. Compared with the primiparous group, the secundiparous group had a significantly higher rate of births by cesarean section (42.55% vs 25.06%; P<0.05). The percentages of neonatal respiratory distress syndrome (NRDS; 8.6% vs 3.4%) and transient tachypnea of the newborn (TTN; 7.2% vs 2.6%; P<0.05) in hospitalized neonates from the secundiparous group were significantly higher than in those from the primiparous group.

CONCLUSIONS

Elderly parturient women are not the major population of secundiparous parturients. The neonates of secundiparous mothers have a higher rate of births by cesarean section, which might be associated with increased percentages of NRDS and TTN in hospitalized neonates from the secundiparous mothers.

Elevated airway liquid volumes at birth: a potential cause of transient tachypnea of the newborn

Excessive liquid in airways and/or distal lung tissue may underpin the respiratory morbidity associated with transient tachypnea of the newborn (TTN). However, its effects on lung aeration and respiratory function following birth are unknown. We investigated the effect of elevated airway liquid volumes on newborn respiratory function. Near-term rabbit kittens (30 days gestation; term ~32 days) were delivered, had their lung liquid-drained, and either had no liquid replaced (control; n = 7) or 30 ml/kg of liquid re-added to the airways [liquid added (LA); n = 7]. Kittens were mechanically ventilated in a plethysmograph. Measures of chest and lung parameters, uniformity of lung aeration, and airway size were analyzed using phase contrast X-ray imaging. The maximum peak inflation pressure required to recruit a tidal volume of 8 ml/kg was significantly greater in LA compared with control kittens (35.0 ± 0.7 vs. 26.8 ± 0.4 cmH2O, P < 0.001). LA kittens required greater time to achieve lung aeration (106 ± 14 vs. 60 ± 6 inflations, P = 0.03) and had expanded chest walls, as evidenced by an increased total chest area (32 ± 9%, P < 0.0001), lung height (17 ± 6%, P = 0.02), and curvature of the diaphragm (19 ± 8%, P = 0.04). LA kittens had lower functional residual capacity during stepwise changes in positive end-expiratory pressures (5, 3, 0, and 5 cmH20). Elevated lung liquid volumes had marked adverse effects on lung structure and function in the immediate neonatal period and reduced the ability of the lung to aerate efficiently. We speculate that elevated airway liquid volumes may underlie the initial morbidity in near-term babies with TTN after birth.

NEW & NOTEWORTHY Transient tachypnea of the newborn reduces respiratory function in newborns and is thought to result due to elevated airway liquid volumes following birth. However, the effect of elevated airway liquid volumes on neonatal respiratory function is unknown. Using phase contrast X-ray imaging, we show that elevated airway liquid volumes have adverse effects on lung structure and function in the immediate newborn period, which may underlie the pathology of TTN in near-term babies after birth.

Association Between Planned Cesarean Delivery and Neonatal Mortality and Morbidity in Twin Pregnancies

OBJECTIVE

To evaluate the association between the planned mode of delivery and neonatal mortality and morbidity in an unselected population of women with twin pregnancies.

METHODS

The JUmeaux MODe d'Accouchement (JUMODA) study was a national prospective population-based cohort study. All women with twin pregnancies and their neonates born at or after 32 weeks of gestation with a cephalic first twin were recruited in 176 maternity units in France from February 2014 to March 2015. The primary outcome was a composite of intrapartum mortality and neonatal mortality and morbidity. Comparisons were performed according to the planned mode of delivery, planned cesarean or planned vaginal delivery. The primary analysis to control for potential indication bias used propensity score matching. Subgroup analyses were conducted, one according to gestational age at delivery and one after exclusion of high-risk pregnancies.

RESULTS

Among 5,915 women enrolled in the study, 1,454 (24.6%) had planned cesarean and 4,461 (75.4%) planned vaginal deliveries, of whom 3,583 (80.3%) delivered both twins vaginally. In the overall population, composite neonatal mortality and morbidity was increased in the planned cesarean compared with the planned vaginal delivery group (5.2% compared with 2.2%; odds ratio [OR] 2.38, 95% confidence interval [CI] 1.86-3.05). After matching, neonates born after planned cesarean compared with planned vaginal delivery had higher composite neonatal mortality and morbidity rates (5.3% compared with 3.0%; OR 1.85, 95% confidence interval 1.29-2.67). Differences in composite mortality and morbidity rates applied to neonates born before but not after 37 weeks of gestation. Multivariate and subgroup analyses after exclusion of high-risk pregnancies found similar trends.

CONCLUSION

Planned vaginal delivery for twin pregnancies with a cephalic first twin at or after 32 weeks of gestation was associated with low composite neonatal mortality and morbidity. Moreover, planned cesarean compared with planned vaginal delivery before 37 weeks of gestation might be associated with increased composite neonatal mortality and morbidity.

Intrapartum and neonatal outcomes in singleton pregnancies following conception by assisted reproduction techniques

BACKGROUND

To characterise maternal demographics and ascertain whether clinically important differences exist in the intrapartum and neonatal outcomes associated with assisted reproductive technology (ART).

MATERIALS AND METHODS

A retrospective study was undertaken between January 2007 and December 2013 of all singleton pregnancies conceived via ART at a major tertiary unit in Brisbane, Australia. Intrapartum outcomes were mode of delivery and indication for emergency caesarean. Neonatal outcomes investigated were gestation at delivery, birth weight, Apgar scores, acidosis at birth, respiratory distress, need for resuscitation, admission to neonatal intensive care and stillbirth.

RESULTS

There were 4733 (7.4%) ART and 59 277 (92.6%) spontaneous conception pregnancies. Women who conceived using ART were less likely to have a spontaneous vaginal delivery (odds ratio (OR) 0.60, 95% CI 0.57-0.64) and were more likely to require operative or assisted birth: elective caesarean (adjusted OR (aOR) 1.31, 95% CI 1.22-1.40), emergency caesarean (aOR 1.19, 95% CI 1.09-1.28), or instrumental delivery (aOR 1.45, 95% CI 1.32-1.58). Neonates who were conceived using ART were less likely to be born at term (aOR 0.64, 95% CI 0.58-0.71) and have lower birth weights. No differences were observed in rates of respiratory distress, admission to the neonatal intensive care unit, or stillbirth between the ART and spontaneous conception cohorts. The odds of neonatal acidosis (OR 0.71, 95% CI0.63-0.81) were lower in the ART cohort.

CONCLUSION

Although higher rates of operative deliveries were seen for women who conceive using ART, neonatal outcomes were generally no different between the two cohorts.

Impact of antenatal oxytocin infusion on neonatal respiratory morbidity associated with elective cesarean section

INTRODUCTION

This study was designed to estimate respiratory morbidity associated with elective cesarean section (ECS) and to determine the effect of antenatal oxytocin exposure on this morbidity.

MATERIAL AND METHODS

Nine hundred and sixty-five neonates ≥ 37 weeks' gestation delivered by cesarean section during 1 year were included in this retrospective study and classified into two groups according to oxytocin exposure before cesarean deliveries. Respiratory morbidity for each group was recorded and statistically analyzed.

RESULTS

Transient tachypnea of newborn (TTN) was significantly more frequent in group II (ECS group) than in group I (cesarean section after oxytocin exposure) (8.19% vs. 2.92%; respectively, p = 0.0006). Mechanical ventilation, continuous positive airway pressure (CPAP) and oxygen therapy were significantly more frequent in group II than in group I (1.78%, 2.14% and 4.28% versus 0.44%, 0.58% and 1.46%, respectively; p = 0.039, and p = 0.033 and p = 0.009, respectively). The number of newborns admitted to the neonatal unit and neonatal intensive care unit (NICU) was significantly higher in group II than in group I (6.41% and 2.14% vs. 2.05% and 0.58%, respectively; p = 0.001 and p = 0.033, respectively). Surfactant, fluid therapies and parenteral nutrition were significantly more frequent in group II than in group I (2.14%, 4.28% and 2.49% vs. 0.15%, 1.46% and 0.73%, respectively; p = 0.001, p = 0.009 and p = 0.02, respectively).

CONCLUSIONS

Neonatal respiratory morbidity associated with ECS significantly decreased after antenatal oxytocin exposure. A significant reduction of neonatal respiratory morbidity would be achieved if ECS were performed after 39 weeks' gestation.

Strategies for managing transient tachypnoea of the newborn - a systematic review

OBJECTIVE

To conduct a systematic review of strategies for the management of transient tachypnoea of the newborn (TTN).

METHODS

The Cochrane Collaboration and PRISMA guidelines were used for conducting and reporting this systematic review, respectively. The Cochrane Central Register of Controlled Trials, PubMed, CINAHL and EMBASE databases were searched in February 2016. Only randomised and quasi-randomised controlled trials (RCTs) assessing any intervention for the management of TTN in infants <7 days of age, born at 35 or more weeks with a clinical diagnosis of TTN were eligible for inclusion. Primary outcomes included the duration of respiratory support, oxygen support, tachypnoea and hospitalisation.

RESULTS

Nine RCTs with moderate risk of bias were included. The interventions assessed included furosemide (2 trials, n = 100), inhaled salbutamol (2 trials, n = 94), inhaled epinephrine (1 trial, n = 20), restrictive fluids (2 trials, n = 146) and non-invasive ventilation (2 trials, n = 80). Amongst all interventions, inhaled salbutamol significantly reduced the duration of hospitalisation (2 trials, n = 94) [mean difference (MD) - 1.63 days (95% CI -2.71 to -0.55); p = 0.003] and duration of oxygen requirement (1 trial, n = 37) [MD - 43.10 h (95% CI -81.82 to -4.38; p = 0.03] without adverse effects.

CONCLUSION

Limited low-quality evidence exists on the effects of different management strategies for TTN. The safety and efficacy of inhaled salbutamol in the treatment of TTN can be assessed in a large RCT.

Megacystis microcolon intestinal hypoperistalsis syndrome: Case series and updated review of the literature with an emphasis on urologic management

INTRODUCTION

Megacystis microcolon intestinal hypoperistalsis (MMIHS) is a rare disorder characterized by distended nonobstructed bladder, microcolon, and decreased intestinal peristalsis. MMIHS has a particularly poor prognosis; however, when appropriately managed, survival can be prolonged.

STUDY DESIGN

A systematic review (1996-2016) was performed with the key words "megacystis microcolon intestinal hypoperistalsis syndrome." In addition, a case series of four patients is presented as well as algorithms for the diagnosis and treatment of MMIHS.

RESULTS

135 patients with MMIHS were identified in the literature. 73% (88/121) of the patients were female, 65% underwent diagnostic biopsy (64/99), and 63% (66/106) were identified with prenatal imaging. The majority of patients were treated with TPN as well as gastrostomy or ileostomy and CIC, however 15% (18/116) received multivisceral or intestinal transplant, and 30% (22/73) had a vesicostomy. The survival rate was 57% (68/121).

CONCLUSION

Appropriate management of MMIHS patients is crucial. An enlarged, acontractile bladder in a child with bowel motility problems should be considered diagnostic. Bladder distension can be managed with CIC or vesicostomy in addition to prophylactic antibiotics if frequent urinary tract infections are present. These patients often require gastrostomy or ileostomy as well as total parenteral nutrition. This management has led to significant improvement in survival rates.

Respiratory transition in the newborn: a three-phase process

We propose that the respiratory transition at birth passes through three distinct, but overlapping phases, which reflect different physiological states of the lung. Accordingly, respiratory support given to infants should be optimised to suit the underlying physiological state of the lung as it passes through each phase. During the first phase, the airways are liquid-filled and so no pulmonary gas exchange can occur. Respiratory support should, therefore, be focused on clearing the gas exchange regions of liquid. In the absence of gas exchange, little or no CO2will accumulate within the airways and, therefore, interrupting inflation pressures to allow the lung to deflate and exhale CO2is unnecessary. This is the primary rationale for administering a sustained inflation at birth. During the second phase, the gas exchange regions are mostly cleared of liquid, allowing pulmonary gas exchange to commence. However, the liquid cleared from the airways resides within the tissue during this phase, which increases perialveolar interstitial tissue pressures and the risk of liquid re-entry back into the airways. As a result, respiratory support should be optimised to minimise alveolar re-flooding during expiration, which can be achieved by applying an end-expiratory pressure. The third and final phase occurs when the liquid is eventually cleared from lung tissue. Although gas exchange may be restricted by lung immaturity, injury and inflammation during this phase, considerations of how fetal lung liquid can adversely affect lung function are no longer relevant.

Cephalometric comparison of cesarean and normal births

Objective:

The aim of this study was to compare cephalometric variables of subjects with normal and cesarean births.

Materials and Methods:

Ninety age- and gender-matched patients, who were treated in Gaziantep University, Faculty of Dentistry Orthodontics Department were equally divided into normal and cesarean groups according to the birth methods reported by their mothers. To eliminate the negative effects of being different in terms of age and gender among parameters, control, and patient groups were matched in the present study. Pretreatment cephalometrics radiographs were used. Six measurements representing sagittal and vertical relationships were evaluated from pretreatment cephalograms using Dolphin Imaging Orthodontics Software was used in this issue by an orthodontist. Kolmogorov–Smirnov test, Student's t-test, and Mann–Whitney U-test were used for statistical comparisons.

Results:

A point-nasion-B point angle (ANB) and Wits values were higher in the normal group, while sella-nasion-A point angle, sella-nasion-B point angle, Frankfort horizontal-mandibular plane angle, and gonion-gnathion-SN plane angle values were higher in the cesarean group. However, the groups showed no significant differences (P > 0.05). ANB angle and Wits values showed high correlation.

Conclusions:

Within the study limitations, the results suggest that the birth method may not have a considerable effect on the development of the craniofacial skeletal system.

Caesarean Section has no impact on lung function at the age of 15 years

BACKGROUND

Epidemiological studies and meta-analyses have shown an increased risk of childhood asthma for children born by Caesarean Section (C-Section).

OBJECTIVE

To investigate the effect of delivery by C-Section on lung function and asthma in adolescence in a population-based prospective birth cohort of healthy full term newborns.

METHODS

Questionnaire data on mode of delivery and asthma as well as spirometric measurements were available for 1850 adolescents at the age of 15 years, who participated in a follow-up examination of the GINIplus study. Linear regression models were used to examine associations between mode of delivery and lung function parameters. Two reference populations (Lunokid and GLI) were used to calculate the standardized z-scores of lung function parameters.

RESULTS

The mean difference in lung function parameters for adolescents born by C-Section, compared to vaginal delivery was not statistically significant. The risk for developing asthma by the age of 15 years was not higher in children born by C-Section-OR: 0.87 (95% CI: 0.57, 1.33) adjusted for sex, age, study center, and parental education level.

CONCLUSION

C-Section was not associated with impaired lung function or an increased risk of asthma at the age of 15 years in our birth cohort of healthy full term neonates.

Protocol for a randomised controlled trial of fetal scalp blood lactate measurement to reduce caesarean sections during labour: the Flamingo trial [ACTRN12611000172909]

BACKGROUND

The rate of caesarean sections around the world is rising each year, reaching epidemic proportions. Although many caesarean sections are performed for concerns about fetal welfare on the basis of abnormal cardiotocography, the majority of babies are shown to be well at birth, meaning that the operation, with its inherent short and long term risks, could have been avoided without compromising the baby's health. Previously, fetal scalp blood sampling for pH estimation was performed in the context of an abnormal cardiotocograph, to improve the identification of babies in need of expedited delivery. This test has largely been replaced by lactate measurement, although its validity is yet to be established through a randomised controlled trial. This study aims to test the hypothesis that the performance of fetal scalp blood lactate measurement for women in labour with an abnormal cardiotocograph will reduce the rate of birth by caesarean section from 38 % to 25 % (a 35 % relative reduction).

METHODS/DESIGN

Prospective unblinded randomised controlled trial conducted at a single tertiary perinatal centre. Women labouring with a singleton fetus in cephalic presentation at 37 or more weeks' gestation with ruptured membranes and with an abnormal cardiotocograph will be eligible. Participants will be randomised to one of two groups: fetal monitoring by cardiotocography alone, or cardiotocography augmented by fetal scalp blood lactate analysis. Decisions regarding the timing and mode of delivery will be made by the treating team, in accordance with hospital protocols. The primary study endpoint is caesarean section with secondary outcomes collected from maternal, fetal and neonatal clinical course and morbidities. A cost effectiveness analysis will also be performed. A sample size of 600 will provide 90 % power to detect the hypothesised difference in the proportion of women who give birth by caesarean section.

DISCUSSION

This world-first trial is adequately powered to determine the impact of fetal scalp blood lactate measurement on rates of caesarean section. Preventing unnecessary caesarean sections will reduce the health and financial burdens associated with this operation, both in the index and any future pregnancies.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ACTRN12611000172909.