Physiology of fetal lung fluid clearance and the effect of labor

Amniotic fluid: its role in fetal development and beyond

Amniotic fluid is a complex biological medium that surrounds the fetus and offers not only mechanical protection but also provides nutrition and plays a critical role in normal fetal growth, organogenesis, and potentially fetal programming. Despite its importance, the biology of amniotic fluid has been understudied because of ethical and technical challenges in obtaining amniotic fluid samples from healthy human pregnancies, translational limitations of animal models to humans due to species-specific differences. Recent progress in understanding its dynamic physiology, composition, and clinical applications has advanced prenatal care and facilitated improved diagnostic and therapeutic strategies. As research continues to elucidate the complexities and evolutionary function of amniotic fluid, its increasingly recognized role in maternal-fetal medicine and its potential to transform clinical practice will only become more evident. The purpose of this review is to underscore the key roles of amniotic fluid in shaping fetal development and therapeutic potential.

Lung ultrasound to evaluate the outcome and prognosis of transient tachypnea of the newborn

Background/Objectives

Transient tachypnea of the newborn (TTN) is generally self-limiting. The increasing incidence of severe cases and lack of comprehensive studies on its clinical outcomes and influencing factors highlight the need for improved diagnostic and monitoring tools. This study aimed to assess the lung ultrasonographic features, recovery durations, and factors influencing TTN.

Methods

Two hundred neonates with wet lungs were selected as the TTN group and divided into mild (132/200) and severe (68/200) groups. Two hundred neonates without pulmonary disease served as controls. The acute-phase lung ultrasonographic features of the two groups were compared. According to the clinical recovery duration, TTN group was divided into group A (<5 days, 191/200) and group B (≥5 days, 9/200). Univariate and multivariate logistic regression analyses were used to analyze the relationship between clinically relevant factors and the recovery time.

Results

The time that was required for the 200 neonates to fully recover without symptoms was 2.3 ± 1.33 days. The average clinical recovery durations of neonates with mild illness, those who required non-invasive ventilation, and those who required invasive ventilation were 1.42 ± 0.50, 3.36 ± 0.51, and 6.00 ± 1.12 days, respectively. The differences between the groups were significant (P < 0.05). Type II respiratory failure, acute respiratory distress syndrome (ARDS), persistent pulmonary hypertension of the newborn (PPHN), and heart failure were important factors affecting the recovery time.

Conclusion

The lung ultrasonographic signs differed based on the degree of wet lungs. Moreover, type II respiratory failure, ARDS, PPHN, and heart failure are important factors prolonging the course of TTN in neonates.

Labor Status at Delivery and Lung Function in Extremely Prematurely Born Young Adults

BACKGROUND

There has been conflicting evidence regarding the impact of mode of delivery on respiratory outcomes in later childhood and adulthood. It is possible labor status, rather than mode of delivery, influences later respiratory morbidity. We hypothesized that extremely premature infants born to mothers in labor would have better lung function at follow-up than those born to mothers not in labor.

METHODS

We reviewed data from the United Kingdom High-Frequency Oscillation Study. Lung function testing was performed on young people aged 16-18 years born before 29 weeks of gestation. Linear mixed models were used to adjust lung function for maternal and neonatal factors and for the clustering due to multiple births.

RESULTS

One hundred and fifty subjects underwent lung function testing. Young adults born to mothers in labor had better mean Forced Expiratory Flow75 (FEF75) compared to those born to mothers not in labor (adjusted difference 0.50 [95% CI: 0.02, 0.99]). Similar significant differences were noted in FEF50 (0.45 [-0.05, 0.85]), and FEF25-75 (0.53 [0.05, 1.01]).

CONCLUSION

Our study demonstrates that amongst individuals born very prematurely, those whose mothers were in labor before delivery had better small airway function at 16-19 years of age.

Microbubble-laden aerosols improve post-nasal aerosol penetration efficiency in a preterm neonate model

Nebulized lung surfactant therapy has been a neonatology long-pursued goal. Nevertheless, many clinical trials have yet to show a clear clinical efficacy of nebulized surfactant, which, in part, is due to the technical challenges of delivering aerosols to the lungs of preterm neonates. The study aimed to test microbubbles for improving lung deposition in preterm neonates. An in vitro testing method was developed to replicate the clinical environment; it used a 3D-printed preterm neonate model, connected to a high-flow nasal cannula (HFNC) and a vibrating mesh nebulizer. The flow rate of the HFNC mirrored that used in the clinics (i.e., 4, 6, and 8 L/min). Followingly, the lung penetrations of aerosols with and without microbubbles were compared. The aerodynamic diameter of aerosols with microbubbles (MMAD=1.75 μm) was lower than that of the counterpart (MMAD=2.25 μm). Microbubble-laden aerosols had a significantly higher number of microbubbles that were below 1.0 μm. Microbubble-laden aerosols had dramatically higher lung penetration in the preterm model; lung penetration efficiencies were 30.0, 25.5, and 17.5 % at 4, 6, and 8 L/min, respectively, whereas the lung penetration efficiency for conventionally nebulized aerosols was below 1.25 % in the three flow rates.

Maternal COVID-19 infection and risk of respiratory distress syndrome among newborns: a systematic review and meta-analysis

BACKGROUND

The COVID-19 pandemic has significantly impacted public health, with emerging evidence suggesting substantial effects on maternal and neonatal health. This systematic review and meta-analysis aimed to quantify the prevalence and risk of respiratory distress syndrome (RDS) in newborns born to mothers infected with SARS-CoV-2, the virus responsible for COVID-19.

METHODS

We conducted a literature search in Embase, PubMed, and Web of Science up to April 20, without language or date restrictions. Observational studies reporting on the prevalence or risk of RDS among newborns from mothers with confirmed SARS-CoV-2 infection were included. Quality assessment was performed using the JBI tool. Statistical analysis was performed by using R software version 4.3.

RESULTS

Twenty-two studies met the inclusion criteria. The pooled prevalence of RDS among newborns born to COVID-19-infected mothers was 11.5% (95% CI: 7.4-17.3%), with significant heterogeneity (I² = 93%). Newborns from infected mothers had a significantly higher risk of developing RDS, with a pooled risk ratio (RR) of 2.69 (95% CI: 1.77 to 4.17).

CONCLUSION

Newborns born to mothers with COVID-19 have a substantially increased risk of developing RDS. These findings emphasize the need for vigilant monitoring and appropriate management of pregnant women with COVID-19 to mitigate adverse neonatal outcomes.

Knee-to-chest flexion manoeuvre to reduce respiratory distress after planned caesarean birth: a feasibility study

BACKGROUND

Planned caesarean section (CS) is a risk factor for neonatal respiratory distress caused by a greater volume of airway liquid in the absence of uterine contractions.Performing a newly conceptualised knee-to-chest flexion (KCF) manoeuvre at birth, mimicking uterine contraction-induced flexion may aid in expelling excess lung liquid.

OBJECTIVES

To test whether performing a KCF manoeuvre at birth is feasible in infants born after planned CS and to test whether KCF leads to visible expulsion of lung liquid.

METHODS

Single-centre prospective interventional study in term infants born by planned CS at Leiden University Medical Centre, Netherlands. KCF was performed for a maximum of 45 s. Baseline characteristics were collected, primary outcome was ability to perform KCF and secondary outcome was any visible expulsion of fluid.

RESULTS

In 39 infants (mean (SD) gestational age 38.0 (0.7) weeks, birth weight 3537 (440) g), KCF could be performed in 21/39 (54%), whereas 18/39 (46.2%) starting vigorous breathing before KCF could be performed. Notably, visible lung liquid expulsion occurred in 9/21 (43%) infants. KCF duration averaged 29 (18) s. In 13/21 (62 %), KCF was not performed as per standard operating procedure. No adverse events were reported.

CONCLUSION

It is feasible to perform KCF at birth in a large proportion of term infants born by planned CS, with visible expulsion of liquid in a significant proportion of these infants. Training healthcare providers to perform a standardised KCF could increase feasibility and success. Further studies are needed to assess feasibility and effectiveness of KCF.

TRIAL REGISTRATION NUMBER

NL74285.058.20.

Comparative Study of the Safety and Efficacy of Intramuscular Dexamethasone, Betamethasone Phosphate, and Standard Management Protocol in Early-Term Scheduled Caesarean Delivery

Background Babies born between 37 weeks +0 days and 38 weeks +6 days by scheduled caesarean delivery before the onset of labour are more prone to developing respiratory complications than babies delivered between 39 weeks +0 days and 40 weeks +0 days. Antenatal corticosteroids have been used in preterm births for lung maturity. The advantages of administering antenatal corticosteroids before a scheduled caesarean delivery in the early term remain a subject of debate. While some studies have reported benefits, including a reduction in respiratory issues, the evidence is still inconclusive. The study's main objective is to compare the efficacy and safety of intramuscular dexamethasone and betamethasone phosphate with standard treatment protocols in early-term infants. Methodology A total of 241 pregnant women scheduled for caesarean delivery were screened for eligibility to participate in the study. Out of these, 192 women met the inclusion criteria and were enrolled in the study after providing written informed consent; they were randomised into three groups, with 64 in each group, and were given either betamethasone phosphate or dexamethasone intramuscularly or were considered under standard management protocol (no administration of corticosteroids). The primary comparison was done to observe the development of respiratory distress syndrome, transient tachypnoea in newborns, and the need for neonatal intensive care unit (NICU) admission. Results Among 192 pregnant females observed, the incidence of development of respiratory distress syndrome did not differ significantly between the betamethasone, dexamethasone, and standard management groups, with rates of 6.25%, 7.81%, and 4.7%, respectively. Additionally, out of the 192 infants, 15 required neonatal intensive care, including 6 (9.4%) from the betamethasone group, 5 (7.8%) from the dexamethasone group, and 4 (6.3%) from the standard management group. All of these infants had a maximum stay of four days in the NICU, did not require mechanical support, and improved with oxygen therapy. Conclusion In our study, in early-term gestation, both the corticosteroid groups showed similar effects to those of the standard management group in reducing neonatal morbidity, with no significant statistical difference. Hence, the choice lies with the treating obstetrician to consider the administration of corticosteroids in early-term caesarean deliveries.

Canine pulmonary clearance during feto-neonatal transition according to the type of delivery

The success of immediate adaptation to extrauterine life depends on appropriate lung function, however, elective cesarean section can increase the risk of respiratory distress as a result of reduced pulmonary fluid absorption. This study aimed to evaluate the influence of birth mode on pulmonary clearance and respiratory performance of canine neonates in the transition period. For this purpose, 37 neonates were selected according to the obstetric condition: Vaginal Eutocia (n = 17) and Elective C-section (n = 20). Neonates were evaluated for neonatal vitality score, as well as evaluation of heart and respiratory rates, body temperature and body weight, venous hemogasometric evaluation, blood lactate and glucose, pulse oximetry and radiographic evaluation during the first 24 h of life. Additionally, amniotic fluid electrolyte composition of each puppy was evaluated. There was no influence of the type of delivery on electrolyte composition of canine amniotic fluid and neonatal pulmonary liquid content, analyzed by thoracic X-Rays. On the other hand, elective cesarean section delayed pulmonary adaptation, resulting in hypoxemia and less efficient compensatory response to acid-base imbalance and thermoregulation. In conclusion, elective c-section does not delay pulmonary clearance, whilst alters pulmonary adaptation by less efficient gas exchange and lower oxygenation, hindering the compensatory response to acid-base imbalance during the fetal-neonatal transition in dogs.

Understanding Obstetrical Surgical Planning for the Pediatrician

Cesarean deliveries are common in the United States, occurring in approximately one-third of deliveries in 2021. Given this high rate of cesarean deliveries, it is important for all clinicians caring for the pregnant person-infant dyad to be educated about cesarean deliveries. In this review, we describe the indications for cesarean delivery, the evidence-based practices of preoperative planning to ensure safe deliveries, and the clinical decision-making behind various cesarean incisions. In addition, we discuss the most common complications of cesarean deliveries for the pregnant person-infant dyad.

Incidence of neonatal respiratory morbidity after vaginal and caesarean delivery in the late-preterm and term period - a retrospective cohort study

BACKGROUND

Respiratory distress syndrome is a leading cause of neonatal intensive care unit admissions for late preterm (34-36 weeks gestational age) and term infants (37-41 weeks). The risk for respiratory morbidity appears to increase after an elective caesarean delivery and might be reduced after antenatal corticosteroids. However, before considering antenatal corticosteroids for women at high risk of preterm birth after 34 weeks, the incidence of respiratory distress syndrome and the effect of delivery mode on this incidence requires further evaluation. Therefore, this study aimed to investigate the relationship between respiratory distress syndrome incidence and delivery mode in late preterm and term infants.

METHODS

In this retrospective cohort study, the clinical databases of the University Hospitals of Zurich and Basel were queried regarding all live births between 34 + 0 and 41 + 6 weeks. Neonatal intensive care unit admissions due to respiratory distress syndrome were determined and analysed in regard to the following delivery modes: spontaneous vaginal, operative vaginal, elective caesarean, secondary caesarean and emergency caesarean.

RESULTS

After excluding malformations (n = 889) and incomplete or inconclusive data (n = 383), 37,110 infants out of 38,382 were evaluated. Of these, 5.34% (n = 1980) were admitted to a neonatal intensive care unit for respiratory distress syndrome. Regardless of gestational age, respiratory distress syndrome in infants after spontaneous vaginal delivery was 2.92%; for operative vaginal delivery, it was 4.02%; after elective caesarean delivery it was 8.98%; following secondary caesarean delivery, it was 8.45%, and after an emergency caesarean it was 13.3%. The risk of respiratory distress syndrome was higher after an elective caesarean compared to spontaneous vaginal delivery, with an odds ratio (OR), adjusted for gestational age, of 2.31 (95% CI 1.49-3.56) at 34 weeks, OR 5.61 (95% CI 3.39-9.3) at 35 weeks, OR 1.5 (95% CI 0.95-2.38) at 36 weeks, OR 3.28 (95% CI 1.95-5.54) at 37 weeks and OR 2.51 (95% CI 1.65-3.81) at 38 weeks. At 39 weeks, there was no significant difference between the risk of respiratory distress syndrome after an elective caesarean vs. spontaneous vaginal delivery. Over the study period, gestational age at elective caesarean delivery remained stable at 39.3 ± 1.65 weeks.

CONCLUSION

The incidence of respiratory distress syndrome following an elective caesarean is up to threefold higher in infants born with less than 39 weeks gestational age compared to those born by spontaneous vaginal delivery. Therefore - and whenever possible - an elective caesarean delivery should be planned after 38 completed weeks to minimise the risk of respiratory morbidity in neonates.

Optimizing Newborn Outcomes in Cesarean Sections: A Comparative Analysis of Stress Indicators under General and Spinal Anesthesia

BACKGROUND AND OBJECTIVES

The moment of birth represents a complex physiological process that is followed by adaptive changes in the vital systems of the newborn. Such reactions have their positive but also negative effects. The aim of this research was to determine the difference in laboratory values of stress indicators in newborn children delivered by cesarean section (CS) with general and spinal anesthesia. We attempted to make a recommendation about the optimal type of anesthesia based on our results.

MATERIALS AND METHODS

The study was performed on 150 healthy term newborns delivered by urgent or planned CS. Samples for adrenocorticotropic hormone (ACTH), cortisol, triglycerides, and interleukin-6 (IL-6) were analyzed.

RESULTS

Leukocyte numbers, triglycerides, and blood sugar values were normal for the newborns' age, with statistically significantly lower values of blood sugar and triglycerides in newborns delivered by CS in spinal anesthesia (p < 0.005) compared to general anesthesia. There were no significant differences in ACTH, cortisol, and IL-6 levels between those newborns delivered via CS after spinal or general anesthesia.

CONCLUSIONS

In cases where vaginal delivery is not possible, when CS is indicated, the use of well-controlled spinal anesthesia is followed by lower degrees of metabolic, inflammatory, and stress responses and better vitality of the baby upon birth.

Clear amniotic fluid aspiration syndrome: A novel description of an old entity

BACKGROUND

Clear amniotic fluid aspiration syndrome (CAF-AS) is a very rare event occurring in 0.25% of our term clear amniotic fluids deliveries. The study's aims were: 1. to characterize the risk factors and outcomes associated with Clear Amniotic Fluid Aspiration Syndrome and 2. to compare the outcomes of Clear Amniotic Fluid Aspiration to Meconium Aspiration.

METHODS

This was an observational study over a 22-year period in a single level-3 medical center. Compared were parturient/labor characteristics and neonatal outcomes in cases with suspected Clear Amniotic Fluid Aspiration to cases suspected for Meconium Aspiration.

RESULTS

Out of 79,620 term deliveries there were 66,705 (83.8%) clear amniotic fluids and 12,915 (16.2%) meconium stained amniotic fluid (MSAF). Of neonates born with clear amniotic fluid, 166 (0.25%) were diagnosed with Clear Amniotic Fluid Aspiration Syndrome (CAF-AS), while 202 (15.7%) of those born with MSAF, were diagnosed with aspiration syndrome (MSAF-AS). Both conditions had comparable rates of mild manifestation (67.5% vs 69.2%, p = 0.63). Persistent pulmonary hypertension (PPH) occurred 5 times less in CAF-AS than MSAF-AS (4% vs 20%, OR 0.17, P< 0.0001) Both conditions presented similar rates of surfactant without PPH (11.1% vs 13.4%, p = 0.87). There was 1 postnatal death in CAF-AS vs 10 in MSAF.

CONCLUSION

CAF-AS were quantitatively quite similar in terms of need of actual active intervention of the neonatologists in the delivery room (166 vs 202, i.e. in terms of numbers of cases and not prevalence) to MSAF-AS.We identified in these cases two major specific causes: hyperkinetic explosive deliveries in multiparas and long-lasting episodes of maternal hypotension due to epidural/spinal anaesthesia during labor. Out of 140 million births per year in the world, it should be of concern that 3 million cases are neglected nowadays. Future studies should evaluate if this CAF-AS should benefit from a more active intervention such as immediate endotracheal suction at birth, this clear fluid being very easy to suction.

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.

Preterm birth affects both surfactant synthesis and lung liquid resorption actors in fetal sheep

INTRODUCTION

After birth, the lungs must resorb the fluid they contain. This process involves multiple actors such as surfactant, aquaporins and ENaC channels. Preterm newborns often exhibit respiratory distress syndrome due to surfactant deficiency, and transitory tachypnea caused by a delay in lung liquid resorption. Our hypothesis is that surfactant, ENaC and aquaporins are involved in respiratory transition to extrauterine life and altered by preterm birth. We compared these candidates in preterm and term fetal sheeps.

MATERIALS AND METHODS

We performed cesarean sections in 8 time-dated pregnant ewes (4 at 100 days and 4 at 140 days of gestation, corresponding to 24 and 36 weeks of gestation in humans), and obtained 13 fetal sheeps in each group. We studied surfactant synthesis (SP-A, SP-B, SP-C), lung liquid resorption (ENaC, aquaporins) and corticosteroid regulation (glucocorticoid receptor, mineralocorticoid receptor and 11-betaHSD2) at mRNA and protein levels.

RESULTS

The mRNA expression level of SFTPA, SFTPB and SFTPC was higher in the term group. These results were confirmed at the protein level for SP-B on Western Blot analysis and for SP-A, SP-B and SP-C on immunohistochemical analysis. Regarding aquaporins, ENaC and receptors, mRNA expression levels for AQP1, AQP3, AQP5, ENaCα, ENaCβ, ENaCγ and 11βHSD2 mRNA were also higher in the term group.

DISCUSSION

Expression of surfactant proteins, aquaporins and ENaC increases between 100 and 140 days of gestation in an ovine model. Further exploring these pathways and their hormonal regulation could highlight some new explanations in the pathophysiology of neonatal respiratory diseases.

Ratchet recruitment in the acute respiratory distress syndrome: lessons from the newborn cry

Patients with acute respiratory distress syndrome (ARDS) have few treatment options other than supportive mechanical ventilation. The mortality associated with ARDS remains unacceptably high, and mechanical ventilation itself has the potential to increase mortality further by unintended ventilator-induced lung injury (VILI). Thus, there is motivation to improve management of ventilation in patients with ARDS. The immediate goal of mechanical ventilation in ARDS should be to prevent atelectrauma resulting from repetitive alveolar collapse and reopening. However, a long-term goal should be to re-open collapsed and edematous regions of the lung and reduce regions of high mechanical stress that lead to regional volutrauma. In this paper, we consider the proposed strategy used by the full-term newborn to open the fluid-filled lung during the initial breaths of life, by ratcheting tissues opened over a series of initial breaths with brief expirations. The newborn's cry after birth shares key similarities with the Airway Pressure Release Ventilation (APRV) modality, in which the expiratory duration is sufficiently short to minimize end-expiratory derecruitment. Using a simple computational model of the injured lung, we demonstrate that APRV can slowly open even the most recalcitrant alveoli with extended periods of high inspiratory pressure, while reducing alveolar re-collapse with brief expirations. These processes together comprise a ratchet mechanism by which the lung is progressively recruited, similar to the manner in which the newborn lung is aerated during a series of cries, albeit over longer time scales.

Monitoring of the Healthy Neonatal Transition Period with Serial Lung Ultrasound

Ultrasound has been used to observe lung aeration and fluid clearance during the neonatal transition period, but there is no consensus regarding the optimal timing of lung ultrasound. We aimed to monitor the trend of the serial lung ultrasound score (LUS) and extended LUS (eLUS) throughout the neonatal transition period (≤1, 2, 4, 8, 24, and 48 h after birth), assess any correlation to the clinical presentation (using the Silverman Andersen Respiratory Severity Score (RSS)), and determine the optimal time of the ultrasound. We found both LUS and eLUS decreased significantly after 2 h of life and had similar statistical differences among the serial time points. Although both scores had a positive, moderate correlation to the RSS overall (Pearson correlation 0.499 [p < 0.001] between LUS and RSS, 0.504 [p < 0.001] between eLUS and RSS), the correlation was poor within 1 h of life (Pearson correlation 0.15 [p = 0.389] between LUS and RSS, 0.099 [p = 0.573] between eLUS and RSS). For better clinical correlation, the first lung ultrasound for the neonate may be performed at 2 h of life. Further research is warranted to explore the clinical value and limitations of earlier (≤1 h of life) lung ultrasound examinations.

Changes in the live birth profile in Henan, China: A hospital registry-based study

BACKGROUND

Preterm complications and neonatal asphyxia are the leading causes of death in those under 5 years of age. However, little information exists for the province of Henan, China. The purpose of this study was to explore changes in the live birth profile in a provincial hospital over the past 32 years in Henan, China.

METHODS

A retrospective analysis was conducted to reveal the characteristics of live neonates from 1987 to 2018.

RESULTS

There were 118 253 live births during the period, including 19 798 (16.74%) preterm births. The neonatal death rate was 6.45‰, and the top risk factor was preterm birth complications and birth asphyxia. Before 1998, neonatal death occurred primarily among term infants. Between 1999 and 2018, preterm infants, especially extreme and very preterm infants with very low birthweight, constituted more than half of all mortalities, and the preterm birth rate increased from 5.94% in 1999 to 16.69% in 2018. The risk factors associated with preterm birth were being male (aOR = 1.18, P < 0.001), advanced maternal age (>35 years old; aOR = 1.08, P = 0.008), gravidity ≥2 (aOR = 1.15, P < 0.001), parity ≥2 (aOR = 1.50, P < 0.001), placenta previa (aOR = 7.41, P < 0.001), twin or multiple births (aOR = 10.63, P < 0.001), hypertension (aOR = 2.08, P < 0.001), and rupture of membrane (aOR = 5.03, P < 0.001).

CONCLUSIONS

The preterm birth rate has increased over the past 32 years from 4.98% to 16.69% in a provincial hospital in China. Preterm birth was the leading reason for neonatal death, and birth asphyxia was the major risk factor for death in term infants.

Elucidating the Effect of Antenatal Corticosteroids in the Late Preterm Period

Aim and Objective

To determine the efficacy of antenatal corticosteroids given in the late preterm period.

Methodology

We conducted a retrospective case–control study on patients with singleton pregnancies who were at a risk of delivering in the late preterm period (34 weeks to 36 weeks 6 days). A total of 126 patients who had received antenatal corticosteroids (prenatal administration of either betamethasone or dexamethasone, minimum one dose) during the late preterm period were taken as cases, and 135 patients who had not received steroids antenatally due to various reasons, for example, who were clinically unstable, presented with active bleeding, non-reassuring foetal status that obligated an imminent delivery and those in active labour were included as controls. The various neonatal outcomes like APGAR score at one and five minutes, incidence of admission and duration of stay in neonatal intensive care unit (NICU), respiratory morbidity, requirement of assisted ventilation, intraventricular haemorrhage (IVH) necrotizing enterocolitis, transient tachypnea of the newborn, respiratory distress syndrome, use of surfactant, neonatal hypoglycaemia, hyperbilirubinemia requiring phototherapy, sepsis and neonatal mortality were compared between the two groups.

Results

The baseline characteristics of both groups were comparable. There was a lower incidence of admissions to neonatal intensive care unit (NICU) (15% vs. 26%, p = 0.05), respiratory distress syndrome (5% vs. 13%, p = 0.04), requirement of invasive ventilation (0% vs. 4%, p = 0.04) and hyperbilirubinemia requiring phototherapy (24% vs. 39%, p = 0.02) in the babies of the group that received steroids compared to the control group. The rate of overall respiratory morbidity in the neonates was lowered after giving steroids (16% vs. 28%, p = 0.04). The incidence of neonatal necrotizing enterocolitis, hypoglycaemia, IVH, TTN, sepsis and mortality between the two groups was not significant (p > 0.05).

Conclusion

Antenatal corticosteroids administered to patients between 34 and 36 weeks 6 days of gestation reduce respiratory morbidity, requirement of invasive ventilation, respiratory distress syndrome, hyperbilirubinemia requiring phototherapy and the incidence of NICU admissions in the newborns.

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 to Asian Women Prior to Elective Cesarean Section at Early Term and Effects on Neonatal Respiratory Outcomes

This exploratory study aimed to evaluate the effects of antenatal corticosteroids in singleton pregnancies of Asian women prior to elective cesarean section (CS) at early term on neonatal respiratory outcomes.

METHODS

This is a pilot and pragmatic randomized trial conducted at a university hospital in Malaysia. Women with singleton pregnancies planned for elective CS between 37+0 and 38+6 weeks gestation were randomly allocated into the intervention group, where they received two doses of IM dexamethasone 12 mg of 12 h apart, 24 h prior to surgery OR into the standard care, control group, and both groups received the normal routine antenatal care. The primary outcome measures were neonatal respiratory illnesses, NICU admission and length of stay.

RESULTS

A total of 189 patients were recruited, 93 women in the intervention group and 96 as controls. Between the steroid and control groups, the mean gestation at CS was similar, 266.1 ± 3.2 days (38 weeks) vs. 265.8 ± 4.0 days (37+6 weeks), p = 0.53. The mean birthweight of infants was 3.06 ± 0.41 kg vs. 3.04 ± 0.37 kg, p = 0.71. Infants with respiratory morbidities were primarily due to transient tachypnea of newborn (9.7% vs. 6.3%), and congenital pneumonia (1.1% vs. 3.1%) but none had respiratory distress syndrome. Only four infants required NICU admission (2.2% vs. 3.1%, p = 0.63). Their average length of stay was not statistically different; 3.5 ± 2.1 days vs. 5.7 ± 1.5 days, p = 0.27.

CONCLUSIONS

Elective CS at early term before 39 weeks was associated with a modest overall incidence of neonatal respiratory illness (10.1%) in this Asian population. Antenatal dexamethasone did not diminish infants needing respiratory support, NICU admission and length of stay.

Effect of Antenatal Dexamethasone in Late Preterm Period on Neonatal Hypoglycemia: A Prospective Cohort Study from a Developing Country

OBJECTIVES

This study compared the risk of hypoglycemia within 72 h of life in infants with and without exposure to antenatal dexamethasone in the late preterm period (34-366/7 week's gestational age).

METHODS

This prospective cohort study was conducted in a tertiary care neonatal unit of Eastern India from May 2021 to November 2021. Babies in the exposed group received at least one dose of antenatal dexamethasone in the late preterm period between 7 days before delivery and birth. 'Complete course' of antenatal steroid was defined as four doses of injection dexamethasone at 12 h intervals and <4 doses were considered as 'Partial course'. Primary outcome was incidence of hypoglycemia within 72 h of life, defined as whole blood glucose <45 mg/dl.

RESULTS

Total 298 infants (98 in control, 134 in partial and 66 in complete group) were assessed for final outcome. No significant difference in outcomes were seen in the exposed group compared to unexposed group. However, incidence of hypoglycemia within 72 h (complete vs. partial p= 0.008, complete vs. control p=0.005) and 12 h of life (complete vs. partial p=0.013, complete vs. control p=0.013) was significantly less in complete steroid group. Logistic regression analysis revealed complete course of antenatal corticosteroid significantly decreased the risk of hypoglycemia [adjusted odds ratio, 95% confidence interval (CI) 0.15 (0.03-0.69), p=0.015]. Number needed to be exposed for one additional benefit was 7 (95% CI, 6.35-22.14).

CONCLUSION

Complete course of dexamethasone administered to mothers at risk of late preterm delivery reduces risk of neonatal hypoglycemia within 72 h of life.

Safety and efficacy of a novel double-lumen tracheal tube in neonates with RDS: A prospective cohort study

BACKGROUND

The purpose of this study was to assess the safety and efficacy of a new double-lumen tracheal tube for neonates, with a conventional tracheal tube as a control.

METHOD

Newborns with respiratory distress syndrome (RDS) requiring endotracheal intubation admitted to the tertiary neonatal intensive care unit (NICU) of Qujing Maternal and Child Healthcare Hospital in Yunnan Province between March 2021 and May 2022 were enrolled in this prospective cohort study. Outcome indicators related to effectiveness included mainly the number of intubations, duration of ventilation, duration of oxygenation, and length of stay; safety indicators included any clinical adverse effects during and after intubation. Appropriate stratified and subgroup analyses were performed according to the purpose of intubation, gestational age, and whether the drug was administered via endotracheal tube.

RESULT

A total of 101 neonates were included and divided into two groups based on the choice of tracheal tube: the conventional (n = 50) and new (n = 51) tracheal tube groups. There was no statistical difference between the two groups in terms of adverse effects during and after intubation (p > 0.05). In neonates who were mechanically ventilated without endotracheal surfactant therapy or newborns receiving InSurE technique followed by non-invasive ventilation, no significant differences were found between the two groups regarding any of the efficacy indicators (p > 0.05). However, for neonates on invasive mechanical ventilation, the new tracheal tube allowed for a significant reduction in the duration of mechanical ventilation (96.50[74.00, 144.00] vs. 121.00[96.00, 196.50] hours, p = 0.037) and total ventilation (205.71 ± 80.24 vs. 277.56 ± 117.84 h, p = 0.027), when used as a route for endotracheal drug delivery. Further analysis was performed according to gestational age for newborns requiring intratracheal surfactant administration during mechanical ventilation, and the data showed that for preterm infants, the new tracheal tube not only shortened the duration of mechanical ventilation (101.75 ± 39.72 vs. 155.50 ± 51.49 h, p = 0.026) and total ventilation (216.00 ± 81.60 vs. 351.50 ± 113.79 h, p = 0.010), but also demonstrated significant advantages in reducing the duration of oxygen therapy (9.75 ± 6.02 vs. 17.33 ± 8.43 days, p = 0.042); however, there was no statistical difference in efficacy outcomes between the two groups in full-term infants (p > 0.05).

CONCLUSION

The efficacy and safety of this new tracheal tube are promising in neonates with RDS, especially those requiring surfactant administration via a tracheal tube during mechanical ventilation. Given the limitations of this study, however, the clinical feasibility of this catheter needs to be further confirmed in prospective randomized trials with larger sample sizes.

CLINICAL TRIAL REGISTRATION

http://www.chictr.org.cn/showproj.aspx?proj=122073.

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.

Protocol for a multicenter, double-blind, randomized, placebo-controlled phase III trial of the inhaled β2-adrenergic receptor agonist salbutamol for transient tachypnea of the newborn (the REFSAL trial)

BACKGROUND

Transient tachypnea of the newborn (TTN), which results from inadequate absorption of fetal lung fluid, is the most common cause of neonatal respiratory distress. Stimulation of β-adrenergic receptors enhances alveolar fluid absorption. Therefore, the β2-adrenergic receptor agonist salbutamol has been proposed as a treatment for TTN. This study aims to evaluate the efficacy and safety of salbutamol as supportive pharmacotherapy together with non-invasive nasal continuous positive airway pressure (NIV/nCPAP) for the prevention of persistent pulmonary hypertension of the newborn (PPHN) in infants with TTN.

METHODS AND ANALYSIS

This multicenter, double-blind, phase III trial will include infants with a gestational age between 32 and 42 weeks who are affected by respiratory disorders and treated in eight neonatal intensive care units in Poland. A total of 608 infants within 24 h after birth will be enrolled and randomly assigned (1:1) to receive nebulized salbutamol with NIV or placebo (nebulized 0.9% NaCl) with NIV. The primary outcome is the percentage of infants with TTN who develop PPHN. The secondary outcomes are the severity of respiratory distress (assessed with the modified TTN Silverman score), frequency of need for intubation, duration of NIV and hospitalization, acid-base balance (blood pH, partial pressure of O₂ and CO₂, and base excess), and blood serum ionogram for Na⁺, K⁺, and Ca²⁺.

DISCUSSION

The Respiratory Failure with Salbutamol (REFSAL) study will be the first clinical trial to evaluate the efficacy and safety of salbutamol in the prevention of persistent pulmonary hypertension in newborns with tachypnea, and will improve short term outcomes. If successful, the study will demonstrate the feasibility of early intervention with NIV/nCPAP together with nebulized salbutamol in the management of TTN.

ETHICS AND DISSEMINATION

The study protocol was approved by the Bioethics Committee of the Medical University of Warsaw, Warsaw, Poland on November 16, 2020 (decision number KB/190/2020). All procedures will follow the principles of the Declaration of Helsinki. The results of the study will be submitted for knowledge translation in peer-reviewed journals and presented at national and international pediatric society conferences.

CLINICAL TRIAL REGISTRATION

It is registered at ClinicalTrials.gov NCT05527704, EudraCT 2020-003913-36; Protocol version 5.0 from 04/01/2022.

Respiratory support after delayed cord clamping: a prospective cohort study of at-risk births at ≥35+0 weeks gestation

OBJECTIVE

To identify risk factors associated with delivery room respiratory support in at-risk infants who are initially vigorous and received delayed cord clamping (DCC).

DESIGN

Prospective cohort study.

SETTING

Two perinatal centres in Melbourne, Australia.

PATIENTS

At-risk infants born at ≥35⁺⁰ weeks gestation with a paediatric doctor in attendance who were initially vigorous and received DCC for >60 s.

MAIN OUTCOME MEASURES

Delivery room respiratory support defined as facemask positive pressure ventilation, continuous positive airway pressure and/or supplemental oxygen within 10 min of birth.

RESULTS

Two hundred and ninety-eight infants born at a median (IQR) gestational age of 39⁺³ (38⁺²-40⁺²) weeks were included. Cord clamping occurred at a median (IQR) of 128 (123-145) s. Forty-four (15%) infants received respiratory support at a median of 214 (IQR 156-326) s after birth. Neonatal unit admission for respiratory distress occurred in 32% of infants receiving delivery room respiratory support vs 1% of infants who did not receive delivery room respiratory support (p<0.001). Risk factors independently associated with delivery room respiratory support were average heart rate (HR) at 90-120 s after birth (determined using three-lead ECG), mode of birth and time to establish regular cries. Decision tree analysis identified that infants at highest risk had an average HR of <165 beats per minute at 90-120 s after birth following caesarean section (risk of 39%). Infants with an average HR of ≥165 beats per minute at 90-120 s after birth were at low risk (5%).

CONCLUSIONS

We present a clinical decision pathway for at-risk infants who may benefit from close observation following DCC. Our findings provide a novel perspective of HR beyond the traditional threshold of 100 beats per minute.

Wet lung leading to RDS: the lung ultrasound findings and possible mechanisms - a pilot study from an animal mode

BACKGROUND

Clinically, the lung ultrasound (LUS) showed wet lung could cause respiratory distress syndrome (RDS) in newborns. This work aimed to investigate LUS changes over time and its potential mechanism as alveolar fluid increase in a rabbit model.

METHODS

A total of 35 New Zealand Rabbits were randomly assigned to seven groups. Models of various alveolar fluid levels were induced by infusion of different volumes of normal saline (NS) via the endotracheal tube. LUS was performed before NS infusion, immediately after NS infusion and 4 h after NS infusion. To appraise LUS changes and its potential mechanism as alveolar fluid increase, histopathological examination, the mRNA and protein expression of surfactant protein (SP), and immunohistochemistry (IHC) were performed. The expression levels of SP-B and SP-C proteins were detected using western blotting, and the relative expression levels of SP-B and SP-C mRNA were detected using qRT-PCR.

RESULTS

The results showed that LUS changed from B-line to lung consolidations accompanied by air-bronchograms in some locations of lungs at 4 h when the injection volume ≥ 6 ml/kg. Histopathological examination showed alveoli collapse, inflammatory cell infiltration and alveolar wall thickened. SP-B and SP-C mRNA and protein expression were statistically significantly reduced when the injection volume ≥6 ml/kg (p < .05). IHC staining displayed the same findings.

CONCLUSIONS

As alveolar fluid increase, LUS changed from wet lung to RDS after 4 h. The possible mechanism was that the SP protein expression was significantly reduced. LUS can be used to guide the administration of exogenous surfactant in this situation.

Effect of continuous positive airway pressure versus nasal cannula on late preterm and term infants with transient tachypnea of the newborn

OBJECTIVE

To compare continuous positive airway pressure (CPAP) with nasal cannula (NC) as primary noninvasive respiratory therapy in hypoxic infants for transient tachypnea of the newborn (TTN).

STUDY DESIGN

Retrospective cohort study of infants born at ≥34 weeks of gestation between January 1, 2015 and December 31, 2018.

RESULT

After adjusting for gestational age and birth weight, the maximum fractional inspired oxygen (FiO2) was significantly lower in the CPAP group with an incidence rate ratio (IRR) of 0.85 (95% CI: 0.76-0.96). Although nonsignificant, the CPAP group needed 32% fewer hours on oxygen with an IRR of 0.68 (95% CI: 0.38-1.22). The duration of respiratory support and the incidence of pneumothorax were similar between both groups.

CONCLUSION

Comparing CPAP with NC as initial noninvasive respiratory therapy for TTN, significantly lower maximum FiO2 was observed in the infants of CPAP group without increase in the incidence of pneumothorax.

Antenatal corticosteroids and short-term neonatal outcomes in term and near-term infants of diabetic mothers. Analysis of the Qatar PEARL-peristat registry

OBJECTIVES

A recent discussion surrounding the extension of antenatal corticosteroid (ACS) use beyond 34 weeks of gestation did not include the subgroup of infants of diabetic mothers (IDM). We aimed to examine the association between ACS exposure and outcomes in neonates born at term and at near-term gestation in a large cohort of IDMs.

METHODS

We selected 13976 eligible near-term and term infants who were included in the PEARL-Peristat Perinatal Registry Study (PPS). We assessed the association of ACS exposure with neonatal outcomes in a multivariate regression model that controlled for diabetes mellitus (DM) and other perinatal variables.

RESULTS

The incidence of DM was 28% (3,895 of 13,976) in the cohort. Caesarean section was performed in one-third of the study population. The incidence of ACS exposure was low (1.8%) and typically occurred>2 weeks before delivery. The incidence rates of respiratory distress syndrome (RDS)/ transient tachypnoea of newborns (TTN), all-cause neonatal intensive care unit (NICU) admissions, NICU admissions for hypoglycaemia, and low 5-min Apgar scores were 3.5, 8.8, 1.3, and 0.1%, respectively. In a multivariate regression model, ACS was associated with a slight increase in NICU admissions (OR: 1.44; 95% CI: 1.04-2.03; p=0.028), but not with RDS/TTN.

CONCLUSIONS

Although the low exposure rate was a limitation, ACS administration did not reduce respiratory morbidity in near-term or term IDMs. It was independently associated with an increase in NICU admissions. Randomized controlled trials are required to assess the efficacy and safety of ACS administration in diabetic mothers at late gestation.

Fluid restriction in the management of transient tachypnea of the newborn

BACKGROUND

Transient tachypnea of the newborn (TTN) is caused by delayed clearance of lung fluid at birth. TTN typically appears within the first two hours of life in term and late preterm neonates and is characterized by tachypnea and signs of respiratory distress. Although it is usually a self-limited condition, admission to a neonatal unit is frequently required for monitoring and providing respiratory support. Restricting intake of fluids administered to these infants in the first days of life might improve clearance of lung liquid, thus reducing the effort required to breathe, improving respiratory distress, and potentially reducing the duration of tachypnea.

OBJECTIVES

To evaluate the efficacy and safety of restricted fluid therapy as compared to standard fluid therapy in decreasing the duration of oxygen administration and the need for noninvasive or invasive ventilation among neonates with TTN.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 12), in the Cochrane Library; Ovid MEDLINE and electronic ahead of print publications, in-process & other non-indexed citations, Daily and Versions(R); and the Cumulative Index to Nursing and Allied Health Literature (CINAHL), on December 6, 2019. We also searched clinical trial databases and the reference lists of retrieved articles for randomized controlled trials and quasi-randomized trials.

SELECTION CRITERIA

We included randomized controlled trials (RCTs), quasi-RCTs, and cluster trials on fluid restriction in term and preterm neonates with the diagnosis of TTN or delayed adaptation during the first week after birth.

DATA COLLECTION AND ANALYSIS

For each of the included trials, two review authors independently extracted data (e.g. number of participants, birth weight, gestational age, duration of oxygen therapy, need for continuous positive airway pressure [CPAP], need for mechanical ventilation, duration of mechanical ventilation) and assessed the risk of bias (e.g. adequacy of randomization, blinding, completeness of follow-up). The primary outcome considered in this review was the duration of supplemental oxygen therapy in hours or days. We used the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

Four trials enrolling 317 infants met the inclusion criteria. Three trials enrolled late preterm and term infants with TTN, and the fourth trial enrolled only term infants with TTN. Infants were on various methods of respiratory support at the time of enrollment including room air, oxygen, or nasal CPAP. Infants in the fluid-restricted group received 15 to 20 mL/kg/d less fluid than those in the control group for varying durations after enrollment. Two studies had high risk of selection bias, and three out of four had high risk of performance bias. Only one study had low risk of detection bias, with two at high risk and one at unclear risk. The certainty of evidence for all outcomes was very low due to imprecision of estimates and unclear risk of bias. Two trials reported the primary duration of supplemental oxygen therapy. We are uncertain whether fluid restriction decreases or increases the duration of supplemental oxygen therapy (mean difference [MD] -12.95 hours, 95% confidence interval [CI] -32.82 to 6.92; I² = 98%; 172 infants). Similarly, there is uncertainty for various secondary outcomes including incidence of hypernatremia (serum sodium > 145 mEq/L, risk ratio [RR] 4.0, 95% CI 0.46 to 34.54; test of heterogeneity not applicable; 1 trial, 100 infants), hypoglycemia (blood glucose < 40 mg/dL, RR 1.0, 95% CI 0.15 to 6.82; test of heterogeneity not applicable; 2 trials, 164 infants), endotracheal ventilation (RR 0.73, 95% CI 0.24 to 2.23; I² = 0%; 3 trials, 242 infants), need for noninvasive ventilation (RR 0.40, 95% CI 0.14 to 1.17; test of heterogeneity not applicable; 2 trials, 150 infants), length of hospital stay (MD -0.92 days, 95% CI -1.53 to -0.31; test of heterogeneity not applicable; 1 trial, 80 infants), and cumulative weight loss at 72 hours of age (%) (MD 0.24, 95% CI -1.60 to 2.08; I² = 89%; 2 trials, 156 infants). We did not identify any ongoing trials; however, one trial is awaiting classification.

AUTHORS' CONCLUSIONS

We found limited evidence to establish the benefits and harms of fluid restriction in the management of TTN. Given the very low certainty of available evidence, it is impossible to determine whether fluid restriction is safe or effective for management of TTN. However, given the simplicity of the intervention, a well-designed trial is justified.

Caesarean section and severe upper and lower respiratory tract infections during infancy: Evidence from two UK cohorts

BACKGROUND

Several studies have reported that birth by caesarean section is associated with increased risk of lower respiratory tract infections in the child, but it is unclear whether this applies to any caesarean section or specifically to planned caesareans. Furthermore, although infections of the upper respiratory tract are very common during childhood, there is a scarcity of studies examining whether caesarean is also a risk factor for this site of infection.

METHODS

We obtained data from two UK cohorts: the Millennium Cohort Study (MCS) and linked administrative datasets of the population of Wales through the Secure Anonymised Information Linkage (SAIL) databank. The study focused on term-born singleton infants and included 15,580 infants born 2000-2002 (MCS) and 392,145 infants born 2002-2016 (SAIL). We used information about mode of birth (vaginal delivery, assisted vaginal delivery, planned caesarean and emergency caesarean) from maternal report in the MCS and from hospital birth records in SAIL. Unplanned hospital admission for lower respiratory tract infection (LRTI) was ascertained from maternal report in the MCS and from hospital record ICD codes in SAIL. Information about admissions for upper respiratory tract infection (URTI) was available from SAIL only. Cox regression was used to estimate hazard ratios for each outcome and cohort separately while accounting for a wide range of confounders. Gestational age at birth was further examined as a potential added, indirect risk of planned caesarean birth due to the early delivery.

FINDINGS

The rate of hospital admission for LRTI was 4.6 per 100 child years in the MCS and 5.9 per 100 child years in SAIL. Emergency caesarean was not associated with LRTI admission during infancy in either cohort. In the MCS, planned caesarean was associated with a hazard ratio of 1.39 (95% CI 1.03, 1.87) which further increased to 1.65 (95% CI 1.24, 2.19) when gestational age was not adjusted for. In SAIL, the adjusted hazard ratio was 1.10 (95% CI 1.05, 1.15), which increased to 1.17 (95% CI 1.12, 1.22) when gestational age was not adjusted for. The rate of hospital admission for URTI was 5.9 per 100 child years in SAIL. Following adjustments, emergency caesarean was found to have a hazard ratio of 1.09 (95% CI 1.05, 1.14) for hospital admission for URTI. Planned caesarean was associated with a hazard ratio of 1.11 (95% CI 1.06, 1.16) which increased to 1.17 (95% CI 1.12, 1.22) when gestational age was not adjusted for.

CONCLUSIONS

The risk of severe LRTIs during infancy is moderately elevated in infants born by planned caesarean compared to those born vaginally. Infants born by any type of caesarean may also be at a small increased risk of severe URTIs. The estimated effect sizes are stronger if including the indirect effect arising from planning the caesarean birth for an earlier gestation than would have occurred spontaneously. Further studies are needed to confirm these results.

Lung ultrasound features predict admission to the neonatal intensive care unit in infants with transient neonatal tachypnoea or respiratory distress syndrome born by caesarean section

We aimed to evaluate the reliability of lung ultrasound (LU) to predict admission to the neonatal intensive care unit (NICU) for transient neonatal tachypnoea or respiratory distress syndrome in infants born by caesarean section (CS). A prospective, observational, single-centre study was performed in the delivery room and NICU of Sant'Orsola-Malpighi Hospital in Bologna, Italy. Term and late-preterm infants born by CS were included. LU was performed at 30' and 4 h after birth. LU appearance was graded according to a previously validated three-point scoring system (3P-LUS: type-1, white lung; type-2, black/white lung; type-3, normal lung). Full LUS was also calculated. One hundred infants were enrolled, and seven were admitted to the NICU. The 5 infants with bilateral type-1 lung at birth were all admitted to the NICU. Infants with type-2 and/or type-3 lung were unlikely to be admitted to the NICU. Mean full-LUS was 17 in infants admitted to the NICU, and 8 in infants not admitted. In two separate binary logistic regression models, both the 3P- and the full LUS proved to be independently associated with NICU admission (OR [95% CI] 0.001 [0.000-0.058], P = .001, and 2.890 [1.472-5.672], P = .002, respectively). The ROC analysis for the 3P-LUS yielded an AUC of 0.942 (95%CI, 0.876-0.979; P<.001), while ROC analysis for the full LUS yielded an AUC of 0.978 (95%CI, 0.926-0.997; P<.001). The AUCs for the two LU scores were not significantly different (p = .261).Conclusion: the 3P-LUS performed 30 min after birth proved to be a reliable tool to identify, among term and late preterm infants born to CS, those who will require NICU admission for transient neonatal tachypnoea or respiratory distress syndrome. What is known • Lung ultrasound (LU) has become an attractive diagnostic tool in neonatal settings, and guidelines on point-of-care LU in the neonatal intensive care unit (NICU) have been recently issued. • LU is currently used for diagnosing several neonatal respiratory morbidities and has been also proposed for predicting further intervention, such as NICU admission, need for surfactant treatment or mechanical ventilation in preterm infants. What is new • LU performed 30' after birth and evaluated through a simple three-point scoring system represents a reliable tool to identify, among term and late preterm infants born to caesarean section, those with transient neonatal tachypnoea or respiratory distress syndrome who will require NICU admission. • LU performed in the neonatal period confirms its potential role in ameliorating routine neonatal clinical management.

Recent Advances in Pathophysiology and Management of Transient Tachypnea of Newborn

Transient tachypnea of newborn (TTN) results from failure of the newborn to effectively clear the fetal lung fluid soon after birth. TTN represents the most common etiology of respiratory distress in term gestation newborns and sometimes requires admission to the neonatal intensive care unit. TTN can lead to maternal-infant separation, the need for respiratory support, extended unnecessary exposure to antibiotics and prolonged hospital stays. Recent evidence also suggests that TTN may be associated with wheezing syndromes later in childhood. New imaging modalities such as lung ultrasound can help in the diagnosis of TTN and early management with distending pressure using continuous positive airway pressure may prevent exacerbation of respiratory distress.

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.

The correlation between prelabour rupture of the membranes and neonatal infectious diseases, and the evaluation of guideline implementation in China: a multi-centre prospective cohort study

BACKGROUND

The aim of this study was to describe the epidemiology of prelabour rupture of membranes (PROM) in China and to assess the association between clinical practice following the guidelines and early neonatal infections.

METHODS

We conducted a prospective cohort study of 15926 deliveries in ShenZhen Baoan Women's and Children's Hospital, Xibei Women's and Children's Hospital and Chengdu Women's and Children's Hospital between August 1, 2017, to March 31, 2018. Clinical data were collected for each participant. The epidemiology of PROM was described. The association between PROM with early neonatal infectious outcomes and the influence of the implementation of the guideline on early neonatal infectious outcomes were assessed.

FINDINGS

The incidence of PROM was 18•7%. PROM was showed to be a risk factor for neonatal infectious diseases (adjusted OR 1•92, 95%CI 1•49~2•49, p<0•0001), early-onset pneumonia (EOP) (adjusted OR 1•81, 95%CI 1•29~2•53, p=0•0006) and early-onset sepsis(EOS) (adjusted OR 14•56, 95%CI 1•90~111•67, p=0•01) for term neonates. For term neonates born from mother with PROM, induction of labor according to the guideline was a protective factor for neonatal diseases(adjusted OR 0•50, 95%CI 0•25~1•00, p=0•00498) and EOP(adjusted OR 0•32, 95%CI 0•11~0•91, p=0•03). For preterm neonates born from mother with PROM, using antibiotics according to the guideline showed to be protective for neonatal infectious diseases (adjusted OR 0•14, 95%CI 0•09~0•23, p<0•0001) and EOP (adjusted OR 0•08, 95%CI 0•04~0•14, p<0•0001).

INTERPRETATION

Our study showed the risk of PROM for infectious diseases (including EOP and EOS) and the benefit of the usage of antibiotics according to the guideline for infectious diseases and EOP for preterm neonates.

FUNDING

National Natural Science Foundation of China, Capital Medical Development Research Fund of Beijing.

Does the Caesarean Section Impact on 11β HSD2 and Fetal Cortisol?

Purpose: Comparison of the activity of 11beta-hydroxysteroid dehydrogenase type 2 in the placenta and the umbilical cord blood cortisol level between caesarean sections with or without uterine contraction and vaginal delivery groups. Cortisol is the main stress hormone responsible for the normal adaptation of the neonate to extrauterine life. The disorders resulting from a dysfunction of the 11β-HSD 2–cortisol system can explain the higher risk of developing diseases in children born by caesarean section. Methods: 111 healthy, pregnant women in singular pregnancy at term of delivery were included into the study. The study comprised 11β-HSD 2 in placental tissue from 49 pregnant women delivering by elective caesarean section and 46 pregnant women delivering by vagina. In 16 cases of the elective caesarean section, regular uterine contractions were declared. Cortisol level was estimated in umbilical cord blood directly after delivery. Results: We found no statistically significant differences in the activity of 11β-HSD 2 in placentas delivered via caesarean sections (29.61 on average in elective caesarean sections and 26.65 on average in intrapartum caesarean sections) compared to vaginal deliveries (31.94 on average, p = 0.381), while umbilical cord blood cortisol in the elective caesarean sections group was significantly lower (29.86 on average) compared to the vaginal deliveries (55.50 on average, p < 0.001) and intrapartum caesarean sections (52.27 on average, p < 0.001). Conclusions: The model of placental 11β-HSD 2 activity and umbilical cord blood cortisol concentration seems to be significant in conditions of stress associated with natural uterine contractions in labour.

Respiratory Distress Syndrome in Infants Delivered via Cesarean from Mothers with Preterm Premature Rupture of Membranes: A Propensity Score Analysis

Objective

This study aimed to clarify the effects of cesarean delivery on neonatal respiratory morbidity when women had preterm premature rupture of membranes.

Methods

This retrospective study included women with preterm premature rupture of membranes who delivered from 23 weeks to 33 weeks of gestation between January 2009 and December 2014. Neonatal outcomes were compared between infants delivered by cesarean section and those delivered vaginally. The primary outcome was respiratory distress syndrome (RDS). Neonatal intubation and mechanical ventilation periods were secondary outcomes. Propensity score matching was used to compare outcomes between cesarean and vaginal delivery cases.

Results

There were 101 cesarean deliveries and 89 vaginal deliveries. A comparison of the presence or absence of neonatal complications based on the delivery type indicated a higher occurrence of RDS with cesarean deliveries (P = 0.025). The intubation and mechanical ventilation periods were not significantly longer in neonates delivered via cesarean section.

Conclusions

Cesarean delivery is a risk factor for neonatal RDS in women with preterm premature rupture of membranes. Trials identifying long-term neonatal prognoses are needed to further develop optimal management strategies in such cases.

Internal Version Compared With Pushing for Delivery of Cephalic Second Twins

OBJECTIVE

To assess neonatal morbidity and mortality according to whether cephalic second twins were born after internal version followed by total breech extraction or after instructions to push. We hypothesized that interval version would result in shorter intertwin delivery intervals and lower cesarean delivery rates for the second twin and therefore better neonatal outcomes.

METHODS

These planned analyses of the JUMODA (JUmeaux MODe d'Accouchement) cohort, a national prospective population-based study of twin deliveries, examined births of cephalic second twins after vaginal birth of the first twin at or after 32 weeks of gestation. The internal version group of second twins born in breech presentation after obstetric maneuvers was compared with the pushing group, comprising those born in cephalic presentation. The primary outcome was a composite of neonatal morbidity and mortality. Multivariate modified Poisson regression models were used to control for potential confounders.

RESULTS

Of 2,256 cephalic second twins, 487 (21.6%) were born in breech presentation after internal version and total breech extraction and 1,769 (78.4%) in cephalic presentation after pushing. Composite neonatal morbidity and mortality was not lower in the internal version (17/487 [3.5%]) compared with the pushing group (38/1,769 [2.1%]; adjusted relative risk [aRR] 1.73 [95% CI 0.98-3.05]), although median [quartile 1-quartile 3] intertwin delivery intervals were shorter (5 [4-8] vs 8 [5-12] minutes, P<.001) and the cesarean delivery rate for the second twin lower (5/487 [1.0%] vs 66/1,769 [3.7%], P=.002). Subgroup analyses showed no difference between groups at or after 37 weeks of gestation but higher composite neonatal morbidity and mortality after internal version before 37 weeks (14/215 [6.5%] vs 26/841 [3.1%]; aRR 2.18 [95% CI 1.15-4.13]). Secondary analyses according to center expertise in the overall population and stratified by gestational age yielded concordant results.

CONCLUSION

Although our sample size precluded a robust assessment for small differences in outcomes between groups, internal version followed by total breech extraction of cephalic second twins was not associated with better neonatal outcomes than pushing.

Morphometric and functional pulmonary changes of premature neonatal puppies after antenatal corticoid therapy

Among prematurity complications, the most important disorder is structural immaturity and inadequate production of pulmonary surfactant. Betamethasone is the drug of choice to artificially improve pulmonary capacity, thus we aimed to verify the effect of prenatal maternal treatment on lung development of premature puppies. Pregnant bitches were allocated in Term Group (n = 7), Preterm-Treated Group (interrupted pregnancies with maternal administration of betamethasone; n = 7), Preterm-Control Group (untreated interrupted pregnancies; n = 7), Extremely-Preterm Group (interrupted pregnancies at 55d; n = 6). Puppies were subjected to chest radiographic at birth, morphometric description of pulmonary structures and immunohistochemical analysis of surfactant protein B, proliferating cell nuclear antigen and cytokeratin were performed. In Preterm-Treated Group it was possible to more clearly identify cardiac silhouette and lung parenchyma by X-Ray. Saccular formation was higher in Preterm Groups, while Term Group had higher subsaccular development. Lung septation was higher in Treated and Term Groups. Term Group had higher number of cells marked for SP-B, whereas higher proliferation was observed in Extreme-Preterm and Preterm-Control Groups. Preterm Treated and Term Groups had higher tissue differentiation. In conclusion, antenatal maternal corticotherapy in dogs acted by increasing lung morphology and development of areas of gas exchange, regulate metabolism of pulmonary fluids rather than stimulate surfactant production.

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.

Neonatal weight loss and gain patterns in caesarean section born infants: integrative systematic review

There is evidence that caesarean section delivery can impact on neonatal weight loss and weight gain patterns in the first 5 days of life. We conducted an integrative systematic review to examine the association of mode of delivery on early neonatal weight loss. Pubmed, Cumulative Index to Nursing and Allied Health Literature, Web of Science, Excerpta Medica dataBASE, and Medical Literature Analysis and Retrieval System Online were searched for relevant papers published before June 2019. Reference lists from the relevant papers were then backwards and forwards searched. As neonatal weight loss was reported in different formats, a meta-analysis could not be carried out. Most studies did not distinguish between elective and emergency caesarean sections or instrumental and nonassisted vaginal deliveries. Seven papers were included. All papers except one found that caesarean section was associated with higher weight loss in the early days of life. Two papers presented data from studies on babies followed up to 1 month. One study found that on day 25, babies born by caesarean section had significantly higher weight gain than those born vaginally, while another found that by day 28, babies born vaginally gained more weight per day (11.9 g/kg/day) than those born by caesarean section (10.9 g/kg/day; p = .02). Overall, infants born by caesarean section lost more weight than those born vaginally, but due to the small number of studies included, more are needed to look at this difference and why it may occur. This discrepancy in weight between the two groups may be corrected over time, but future studies will need larger sample sizes and longer follow-up periods to examine this.

Late preterm infants - Changing trends and continuing challenges

Late preterm infants, defined as newborns born between 340/7-366/7 weeks of gestational age, constitute a unique group among all premature neonates. Often overlooked because of their size when compared to very premature infants, this population is still vulnerable because of physiological and structural immaturity. Comprising nearly 75% of babies born less than 37 weeks of gestation, late preterm infants are at increased risk for morbidities involving nearly every organ system as well as higher risk of mortality when compared to term neonates. Neurodevelopmental impairment has especially been a concern for these infants. Due to various reasons, the rate of late preterm births continue to rise worldwide. Caring for this high risk population contributes a significant financial burden to health systems. This article reviews recent trends in regarding rate of late preterm births, common morbidities and long term outcomes with special attention to neurodevelopmental outcomes.

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.

Caesarean section and children's health: A quasi-experimental design

The prevalence of inflammatory child health conditions-such as asthma, eczema, and food allergy-and their associated costs have increased rapidly over the last 30 years. While environmental factors likely underpin these increases, recent studies explain only a fraction of the trend and rely on associational methods. Caesarean (or C-) section rates increased dramatically in the period of interest, and this method of delivery is an understudied environmental factor linked to child health outcomes via the gut microbiome. We fuse 22 years of birth cohort data from the United States National Surveys of Children's Health with C-section rates from the National Vital Statistics System generated for subgroups based on state, sex, race, Hispanic origin, and birth year. Then, we model the effects of C-section on rates of asthma, eczema, and food allergy using a quasi-experimental fixed effects design. We find that C-section significantly predicts food allergy, with qualitatively significant implications.

Postnatal gene expression of airway epithelial sodium transporters associated with birth stress in humans

INTRODUCTION

Lung fluid clearance is essential for successful postnatal pulmonary adaptation. The epithelial sodium channel (ENaC) and Na-K-ATPase, induced by serum- and glucocorticoid-inducible kinase 1 (SGK1) as well as aquaporins (AQP), represent key players in the switch from fetal lung fluid secretion to absorption and in early postnatal lung fluid balance. Birth stress, including a surge in catecholamines, promotes pulmonary adaptation, likely through the augmentation of epithelial sodium reabsorption.

OBJECTIVES

We sought to determine the changes in the airway gene expression of molecules vital to epithelial sodium transport during early pulmonary adaptation, and the association with birth stress reflected in the norepinephrine concentration in the cord blood in humans.

METHODS

We included 70 term newborns: 28 born via vaginal delivery and 42 via elective cesarean section. We determined the norepinephrine concentrations in the cord blood using tandem mass spectrometry and collected nasal epithelial cell samples at 2 min, 1 h, and 24 h postnatally to quantify ENaC, Na-K-ATPase, AQP5, and SGK1 mRNAs using RT-PCR.

RESULTS

The molecular gene expression involved in airway epithelium sodium transport changed markedly within the first hour postnatally. Newborns born via elective cesarean section exhibited a lower expression of ENaC, Na-K-ATPase, and SGK1. Significant correlations existed between the expressions of ENaC, Na-K-ATPase, and SGK1, and the concentration of norepinephrine in the cord blood.

CONCLUSIONS

The association of ENaC, Na-K-ATPase, and SGK1 expression with the cord blood norepinephrine concentration points to the importance of birth stress in promoting lung fluid clearance during early postnatal pulmonary adaptation.

Controversies in antenatal corticosteroids

Antenatal corticosteroids (ACS) successfully reduce the rates of neonatal mortality and morbidity after preterm birth. However, this translational success story is not without controversies. This chapter explores some contemporary controversies with ACS, including the choice of corticosteroid, use in threatened preterm birth less than 24 weeks' gestation, use in late preterm birth, use at term before cesarean delivery, and issues surrounding repeated and rescue dosing of antenatal corticosteroids. The use of ACS in special populations is also discussed. Finally, areas of future research in ACS are presented, focusing on the ability to individualize therapy.