Efficacy of a single dose of antenatal corticosteroids on morbidity and mortality of preterm infants

Equivalence of single and standard doses of antenatal corticosteroids for late preterm neonatal outcomes: insights from a secondary analysis

BACKGROUND

The recent paradigm shift of treating individuals at risk of late preterm birth with antenatal corticosteroids warrants an assessment of the effect of single dosage.

OBJECTIVE

To compare outcomes of neonates born in the late preterm period (34.0-36.6 weeks) after a single dose of antenatal corticosteroids vs placebo.

STUDY DESIGN

We performed a secondary analysis of the Antenatal Late Preterm Steroids trial. All individuals enrolled in the parent trial who received only a single dose of either antenatal corticosteroids or placebo and delivered within 24 hours were included. Primary outcome was a composite of respiratory support at 72 hours, including continuous positive airway pressure or high-flow nasal cannula ≥2 hours, oxygen with an inspired fraction of ≥30% for ≥4 hours, or mechanical ventilation.

RESULTS

Of the 2831 individuals in the parent trial, 1083 (38.3%) met inclusion criteria; of them, 539 (49.8%) received a single dose of antenatal corticosteroids and 544 (50.2%) a single placebo dose. The placebo and antenatal corticosteroids groups had similar demographic and clinical characteristics. There was no difference in the rate of the primary respiratory outcome (adjusted risk ratio, 1.12; 95% confidence interval, 0.85-1.47) or in the rate of respiratory distress syndrome (adjusted risk ratio, 1.47; 95% confidence interval, 0.95-2.26) between those who received a single antenatal corticosteroids dose and placebo. An exploratory stratification by randomization-to-delivery intervals of 12-hour increments also showed no association with lower primary respiratory outcome rates.

CONCLUSION

In individuals with late preterm birth pregnancies who received antenatal corticosteroids and delivered before a second dose, there were no differences in neonatal respiratory morbidities compared with placebo. However, this study is not powered to detect treatment efficacy.

Surfactant status assessment and personalized therapy for surfactant deficiency or dysfunction

Surfactant is a pivotal neonatal drug used both for respiratory distress syndrome due to surfactant deficiency and for more complex surfactant dysfunctions (such as in case of neonatal acute respiratory distress syndrome). Despite its importance, indications for surfactant therapy are often based on oversimplified criteria. Lung biology and modern monitoring provide several diagnostic tools to assess the patient surfactant status and they can be used for a personalized surfactant therapy. This is desirable to improve the efficacy of surfactant treatment and reduce associated costs and side effects. In this review we will discuss these diagnostic tools from a pathophysiological and multi-disciplinary perspective, focusing on the quantitative or qualitative surfactant assays, lung mechanics or aeration measurements, and gas exchange metrics. Their biological and technical characteristics are described with practical information for clinicians. Finally, available evidence-based data are reviewed, and the diagnostic accuracy of the different tools is compared. Lung ultrasound seems the most suitable tool for assessing the surfactant status, while some other promising tests require further research and/or development.

The effect of antenatal corticosteroid use on offspring cardiovascular function: A systematic review

BACKGROUND

Antenatal corticosteroids (ACS) are recommended in threatened preterm labour to improve short-term neonatal outcome. Preclinical animal studies suggest detrimental effects of ACS exposure on offspring cardiac development; their effects in humans are unknown.

OBJECTIVES

To systematically review the human clinical literature to determine the effects of ACS on offspring cardiovascular function.

SEARCH STRATEGY

A systematic review was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines in MEDLINE, EMBASE and Cochrane databases.

SELECTION CRITERIA

Offspring who had been exposed to ACS during fetal life, in comparison with those not receiving steroids, those receiving a placebo or population data, were included. Studies not performed in humans or that did not assess cardiovascular function were excluded.

DATA COLLECTION AND ANALYSIS

Two authors independently screened the studies, extracted the data and assessed the quality of the studies. Results were combined descriptively and analysed using a standardised Excel form.

MAIN RESULTS

Twenty-six studies including 1921 patients were included, most of which were cohort studies of mixed quality. The type of ACS exposure, gestational age at exposure, dose and number of administrations varied widely. Offspring cardiovascular outcomes were assessed from 1 day to 36 years postnatally. The most commonly assessed parameter was arterial blood pressure (18 studies), followed by echocardiography (eight studies), heart rate (five studies), electrocardiogram (ECG, three studies) and cardiac magnetic resonance imaging (MRI, one study). There were no clinically significant effects of ACS exposure on offspring blood pressure. However, there were insufficient studies assessing cardiac structure and function using echocardiography or cardiac MRI to be able to determine an effect.

CONCLUSIONS

The administration of ACS is not associated with long-term effects on blood pressure in exposed human offspring. The effects on cardiac structure and other measures of cardiac function were unclear because of the small number, heterogeneity and mixed quality of the studies. Given the preclinical and human evidence of potential harm following ACS exposure, there is a need for further research to assess central cardiac function in human offspring exposed to ACS.

Partial vs. complete course of antenatal corticosteroid prophylaxis: An Italian single center retrospective study

INTRODUCTION

This study aimed to compare the outcomes of preterm infants given 12 vs. 24mg of betamethasone prophylaxis to understand whether a partial course of antenatal corticosteroids (CCS) could prevent or mitigate the major preterm birth complications.

METHODS

This is a retrospective single-center cohort study including neonates born between 24 and 34 weeks of gestation from 2001 to 2019 at the University Hospital of Udine. The study population was divided into two groups: one group received 12mg, and another received a 24mg dose of betamethasone before the delivery. A separate analysis was performed for single and multiple pregnancies. The two groups were evaluated for various neonatal outcomes.

RESULTS

The study population included a total of 1,258 pregnancies and 1,543 neonates delivered between 24 and 34 weeks of gestation, of which 1,022 (803 single and 219 multiple pregnancies) were exposed to the complete CCS prophylaxis, whereas 236 (192 single and 44 multiple pregnancies) received the incomplete CCS prophylaxis. In single pregnancies, as for maternal characteristics, the most significant differences observed between the two groups are the following: a higher prevalence of spontaneous vaginal deliveries in the incomplete CCS prophylaxis (36.46 vs. 23.91%) and, by contrast, a higher prevalence of cesarean deliveries in the complete CCS prophylaxis group (75.72 vs. 63.02%). As for neonatal outcomes, the low Apgar score in the first and fifth min was significantly more prevalent in the incomplete CCS prophylaxis group compared with the complete CCS prophylaxis group. The group of incomplete CCS prophylaxis reported a higher occurrence of the following outcomes: IVH grade 3-4 (7.81 vs. 3.74%, p < 0.05), PVL (7.29 vs. 1.99% p < 0.05), ROP (23.96 vs. 18.06% p = 0.062), and RDS (84.38 vs. 78.83% p = 0.085). After adjusting for covariates, the complete CCS prophylaxis group in single pregnancies was significantly protective for IVH grade 3-4, PVL, and low Apgar's scores. Similar results were found in multiple pregnancies except for RDS.

DISCUSSION

This retrospective single-center cohort study found that, compared with preterm infants treated with 24mg betamethasone in utero, those given half course of betamethasone had a significantly higher prevalence of IVH grade 3-4, PVL, RDS, and lower Apgar scores at 1 and 5 min. In conclusion, the evidence from this single-center retrospective study supports the preference for the complete CCS prophylaxis in women at risk of preterm birth because of its beneficial effect on the main adverse outcomes.

Techniques to evaluate surfactant activity for a personalized therapy of RDS neonates

According to both European and American Guidelines, preterm neonates have to be treated by nasal continuous air pressure (CPAP) early in the delivery room. The administration of surfactant should be reserved only for babies with respiratory distress syndrome (RDS) with increased oxygen requirement, according to different thresholds of FiO₂. However, these oxygenation thresholds do not fully take into consideration the lung physiopathology and mechanics or the lung surfactant biology of RDS neonates. Since surfactant replacement therapy (SRT) seems to be more effective if it is initiated within the first 3 hours after birth, the use of a reliable bench-to-bedside biological test able to predict as soon as possible the necessity of SRT will help optimise individualised therapies and personalise the actual collective strategy used to treat RDS neonates. With this in mind, in the present review several quantitative and qualitative biological tests to assess the surfactant status in RDS neonates are introduced as potential candidates for the early prediction of SRT requirement, summarising the state-of-the-art in the evaluation of surfactant activity.

Association of antenatal corticosteroids with morbidity and mortality among preterm multiple gestations: meta-analysis of observational studies

OBJECTIVE

This meta-analysis aimed to assess the efficacy of antenatal corticosteroids (ACS) on morbidity and mortality among preterm multiple pregnancies.

METHODS

The PubMed, Embase, Web of Science and Cochrane Library databases were searched for studies investigating the outcomes among preterm multiple gestations following to ACS, from their inception to 1 November 2020. Two authors independently performed the study selection, risk of bias assessment and data extraction. The primary outcomes were respiratory distress syndrome (RDS) and mortality and secondary outcomes included intraventricular haemorrhage (IVH), periventricular leukomalacia (PVL), necrotising enterocolitis, retinopathy of prematurity and bronchopulmonary dysplasia. Pooled ORs were obtained using random effects models. Subgroup analyses were performed to explain heterogeneity by ACS completeness, administration-to-delivery intervals (≤7 days) and single or multicentre.

RESULTS

A total of 16 observational studies with 36 973 newborns were included in the meta-analysis. ACS treatment was associated with a reduction in RDS (OR 0.66; 95% CI 0.54 to 0.82; I2=91.4%; p<0.001), mortality (OR 0.64; 95% CI 0.50 to 0.81; I2=85.9%; p<0.001), IVH (OR 0.67; 95% CI 0.54 to 0.83; I2=77.4%; p<0.001) and PVL (OR 0.65; 95% CI 0.47 to 0.92; I2=75.5%; p<0.001). Subgroup analyses showed ACS completeness, administration-to-delivery interval and multicentre study affected these associations.

DISCUSSION

ACS may be beneficial for reducing the risks of RDS, mortality, IVH and PVL among preterm multiple gestations. The efficacy of ACS could be affected by ACS completeness and administration-to-delivery. More robust evidence on the efficacy of ACS treatment among multiple gestations is warranted.

The impact of betamethasone on fetal pulmonary, umbilical and middle cerebral artery Doppler velocimetry and its relationship with neonatal respiratory distress syndrome

Background

Prenatal corticosteroid administration is known to be an effective strategy in improving fetal pulmonary maturity. This study aimed to evaluate the impact of maternal betamethasone administration on fetal pulmonary and other arteries Doppler velocity and the correlation between RDS development and Doppler indices results.

Methods

Fifty one singleton pregnancies between 26 and 34 gestational weeks with a diagnosis of preterm labor were included in the exposed group and received betamethasone. Fifty one uncomplicated pregnancies were included in the non-exposed group. Fetal pulmonary, umbilical and middle cerebral arteries Doppler parameters were evaluated before and 24 to 48 h after steroid administration in the exposed group and two times at same intervals in the non-exposed group. Maternal records were matched to neonatal charts if delivery happened, and demographic and outcome data were abstracted.

Results

When compared with the nonexposed group, fetuses treated with corticosteroids demonstrated significantly decreased umbilical artery Pulsatility index (PI) and significantly increased the middle cerebral artery PI, pulmonary artery Acceleration time (AT) and pulmonary artery AT/ET (Ejection time), while all other indices remained similar. We found significantly decreased pulmonary artery AT in the fetuses with respiratory distress syndrome (RDS) compared to those that did not.

Conclusions

The results of our study showed that maternal antenatal betamethasone administration caused significant changes in the fetus blood velocity waveforms and also affected the blood flow in the pulmonary artery which led to an increase in the pulmonary artery AT and AT/ET. Among those fetuses with RDS, we found a significant decrease in the pulmonary artery AT, but we did not observe any pulmonary artery AT/ET differences.

Personalized Medicine for the Management of RDS in Preterm Neonates

Continuous positive airway pressure and surfactant represent the first- and second-line treatment for respiratory distress syndrome in preterm neonates, as European and American guidelines, since 2013 and 2014, respectively, started to recommend surfactant replacement only when continuous positive airway pressure fails. These recommendations, however, are not personalized to the individual physiopathology. Simple clinical algorithms may have improved the diffusion of neonatal care, but complex medical issues can hardly be addressed with simple solutions. The treatment of respiratory distress syndrome is a complex matter and can be only optimized with personalization. We performed a review of tools to individualize the management of respiratory distress syndrome based on physiopathology and actual patients' need, according to precision medicine principles. Advanced oxygenation metrics, lung ultrasound, electrical impedance tomography, and both quantitative and qualitative surfactant assays were examined. When these techniques were investigated with diagnostic accuracy studies, reliability measures have been meta-analysed. Amongst all these tools, quantitative lung ultrasound seems the more developed for the widespread use and has a higher diagnostic accuracy (meta-analytical AUC = 0.952 [95% CI: 0.951-0.953]). Surfactant adsorption (AUC = 0.840 [95% CI: 0.824-0.856]) and stable microbubble test (AUC = 0.800 [95% CI: 0.788-0.812]) also have good reliability, but need further industrial development. We advocate for a more accurate characterization and a personalized approach of respiratory distress syndrome. With the above-described currently available tools, it should be possible to personalize the treatment of respiratory distress syndrome according to physiopathol-ogy.

Perinatal risk factors of symptomatic preterm patent ductus arteriosus and secondary ligation

BACKGROUND

There has been conflicting evidence for the association between antenatal factors and the development of symptomatic patent ductus arteriosus (PDA) or failure of pharmacologic treatment, especially for maternal pregnancy-induced hypertension (PIH) or chorioamnionitis. We assessed the perinatal risk factors of symptomatic PDA in preterm infants and those of secondary ligation in infants with pharmacologic treatment for symptomatic PDA using a national cohort.

METHODS

A total of 2961 infants with 22-29 weeks of gestation with symptomatic PDA or no PDA were included from the Korean Neonatal Network database. To identify significant perinatal risk factors associated with symptomatic PDA or secondary ligation, all perinatal factors were included in the univariate and multivariate generalized estimating equation analysis and final model was selected using backward elimination method based on Quasi-likelihood Information Criterion.

RESULTS

Lower gestational age (GA), female gender, maternal PIH and surfactant use were significant risk factors of symptomatic PDA. Antenatal corticosteroid use decreased the risk of symptomatic PDA. For secondary ligation, lower GA and cesarean section were significant risk factors. Adjusted odds ratio (aOR) of PIH as a risk factor of symptomatic PDA was 1.56 [95% confidence interval 1.17-2.08]. In the subgroup analysis according to the GA, lower GA, female gender, multiple pregnancy, maternal PIH and surfactant use increased the risk of symptomatic PDA, and histologic chorioamnionitis and antenatal corticosteroid use decreased the risk of symptomatic PDA only in GA 26-29 weeks group.

CONCLUSION

Lower GA increased the risk of symptomatic PDA and secondary ligation. Maternal PIH and surfactant use increased the risk of symptomatic PDA; however, antenatal corticosteroid use decreased it. Close observation of the clinical symptoms of PDA is needed in preterm infants with maternal PIH.

Echocardiographic Diagnosis and Hemodynamic Evaluation of Patent Ductus Arteriosus in Extremely Low Gestational Age Newborn (ELGAN) Infants

Persistent Patent ductus arteriosus (PDA) is a common finding in extremely low gestational age newborn infants and its prevalence is inversely proportional to the gestational age. The presence of a persistent PDA is associated with increased mortality and several significant morbidities including intraventricular hemorrhage, pulmonary hemorrhage, necrotizing enterocolitis, and chronic lung disease or bronchopulmonary dysplasia. However, treating PDA has not been demonstrated to have beneficial impact on the long term outcomes. Currently there is no consensus on whether to treat the PDA or not, and if treat, when to treat and how to treat. The echocardiography is the investigation of choice to diagnose PDA, estimating the magnitude of shunt volume and assessing its hemodynamic significance, and to exclude/diagnose any associated congenital heart defect before any intervention. Various echocardiographic parameters and staging/scoring systems have been described to help the clincians making the clinical decisions and some of theses scoring systems are quite complex to apply in a busy day to day clinical practice. This concised review paper is focused to help the clinicians in making a clinical decision based upon clincial and echocardiography parameters. Hence, only the parameters which are commonly used and helpful in making the clinical decisions in day to day clincial practice have been described in this paper.

Effects of antenatal betamethasone on preterm human and mouse ductus arteriosus: comparison with baboon data

BACKGROUND

Although studies involving preterm infants ≤34 weeks gestation report a decreased incidence of patent ductus arteriosus after antenatal betamethasone, studies involving younger gestation infants report conflicting results.

METHODS

We used preterm baboons, mice, and humans (≤27^6/7 weeks gestation) to examine betamethasone's effects on ductus gene expression and constriction both in vitro and in vivo.

RESULTS

In mice, betamethasone increased the sensitivity of the premature ductus to the contractile effects of oxygen without altering the effects of other contractile or vasodilatory stimuli. Betamethasone's effects on oxygen sensitivity could be eliminated by inhibiting endogenous prostaglandin/nitric oxide signaling. In mice and baboons, betamethasone increased the expression of several developmentally regulated genes that mediate oxygen-induced constriction (K⁺ channels) and inhibit vasodilator signaling (phosphodiesterases). In human infants, betamethasone increased the rate of ductus constriction at all gestational ages. However, in infants born ≤25^6/7 weeks gestation, betamethasone's contractile effects were only apparent when prostaglandin signaling was inhibited, whereas at 26-27 weeks gestation, betamethasone's contractile effects were apparent even in the absence of prostaglandin inhibitors.

CONCLUSIONS

We speculate that betamethasone's contractile effects may be mediated through genes that are developmentally regulated. This could explain why betamethasone's effects vary according to the infant's developmental age at birth.

Antenatal Corticosteroids: Who Should We Be Treating?

Antenatal corticosteroids remain one of the crucial interventions in those at risk for imminent preterm birth. Therapeutic benefits include reducing major complications of prematurity such as respiratory distress syndrome, intraventricular hemorrhage, and necrotizing enterocolitis, as well as an overall decrease in neonatal deaths. Optimal reductions in neonatal morbidity and mortality require a thoughtful review of the timing of administration. In addition, a thorough understanding is required of which patients maximally benefit from this intervention in the management and counseling of those at risk for preterm birth.

Application of NPE in the assessment of a patent ductus arteriosus

In many preterm infants, the ductus arteriosus remains patent beyond the first few days of life. This prolonged patency is associated with numerous adverse outcomes, but the extent to which these adverse outcomes are attributable to the hemodynamic consequences of ductal patency, if at all, has not been established. Different treatment strategies have failed to improve short-term outcomes, with a paucity of data on the correct diagnostic and pathophysiological assessment of the patent ductus arteriosus (PDA) in association with long-term outcomes. Echocardiography is the selected method of choice for detecting a PDA, assessing the impact on the preterm circulation and monitoring treatment response. PDA in a preterm infant can result in pulmonary overcirculation and systemic hypoperfusion, Therefore, echocardiographic assessment should include evaluation of PDA characteristics, indices of pulmonary overcirculation with left heart loading conditions, and indices of systemic hypoperfusion. In this review, we provide an evidence-based overview of the current and emerging ultrasound measurements available to identify and monitor a PDA in the preterm infant. We offer indications and limitations for using Neonatologist Performed Echocardiography to optimize the management of a neonate with a PDA.

Antenatal corticosteroids in the late preterm period: A prospective cohort study

OBJECTIVE

The study objective was to examine the effect of antenatal corticosteroids on the incidence of short-term neonatal morbidities in singletons born during the late preterm period.

STUDY DESIGN

This was a prospective cohort study of singleton gestations at risk of imminent delivery between 34 0/7 and 36 6/7 weeks. Short-term neonatal morbidities were compared between the corticosteroid exposed and non-exposed groups. The rates of Neonatal Morbidity Composite and Any Adverse Neonatal Morbidity were then compared between the two groups.

RESULTS

During the two-year study period, a total of 295 subjects were included. Of those, 74 were exposed to antenatal corticosteroids, while 221 cases constituted the non-exposed group. There was no statistically significant difference in the rate of Any Adverse Neonatal Morbidity (47.3% vs. 40.7% , p = 0.32) or the rate of Neonatal Morbidity Composite (34.4% vs. 37.8% , p = 0.59) between the two groups. Additionally, there was no statistically significant difference in the rates of neonatal intensive care unit admission, respiratory distress syndrome, transient tachypnea of the newborn, hypothermia, and need for phototherapy.

CONCLUSION

Administration of antenatal corticosteroids to parturients at risk of imminent delivery during the late preterm period does not appear to reduce short-term neonatal morbidities.

Evaluation of strategies regarding management of imminent preterm delivery before 32 weeks of gestation: a regional cohort study among 1375 women in the Netherlands

OBJECTIVE

To evaluate the management of imminent preterm delivery with respect to prescription of antenatal corticosteroids (ACS) and referral to a tertiary center.

STUDY DESIGN

A retrospective cohort study existing of 1 perinatal center and 9 referring hospitals. All women who received their first dose of ACS in 1 of the 10 hospitals between 24+0 and 32+0 weeks of gestation and/or delivered before 32 weeks of gestation from 2005 until 2010. Patients were identified using the electronic database of hospital pharmacies. Main outcome measures were time interval from administration to delivery for different indications and number of women who were not referred in time to a tertiary center.

RESULTS

In total, 1375 women received ACS. Main indications were suspected preterm labor (44.7%), preterm prelabor rupture of membranes (15.9%), maternal indication (12.8%), fetal indication (9.2%) and vaginal blood loss (8.4%). Overall, 467 (34.0%) women delivered ≤7 days after ACS administration; 8.7% of women with vaginal blood loss and 54.5% of women with maternal indication. Among the 931 women who received ACS in the secondary hospitals, 452 (48.5%) women were referred to a tertiary hospital and 89 (6.5%) women delivered in a secondary hospital with a gestational age of less than 32 weeks.

CONCLUSION

One-third of all women receiving ACS delivered within 7 days and half of the women who received ACS in a secondary hospital were referred to a tertiary center. There seems to be room for improvement regarding the timing of ACS administration and subsequently referral to a tertiary center.

Effects of a single course versus repeated courses of antenatal corticosteroids on fetal growth, placental morphometry and the differential regulation of vascular endothelial growth factor

AIM

To investigate the impact of antenatal exposure to a single course or repeated courses of dexamethasone (DEX) on neonatal anthropometrics, placental morphometry and potential effect on maternal plasma levels and placental expression of vascular endothelial growth factor (VEGF).

METHODS

Pregnant women between 27 and 32 weeks of gestation who delivered between 28 and 40 weeks and received a single course (n = 38) or repeated courses (n = 33) of DEX were compared to gestational age-matched controls (n = 30). Maternal blood samples were obtained, and placental biopsy was taken. Area percent of VEGF immunostaining and villous capillarization index were evaluated using image analysis.

RESULTS

Infants exposed to repeated courses of DEX were significantly associated with decreased birthweight, body length, head circumference and placental weight compared with controls (P = 0.011, P < 0.001, P = 0.004, P < 0.001, respectively) and with the group that received a single course of DEX (P = 0.021, P = 0.020, P = 0.049, P = 0.010, respectively). There was a significant decrease in maternal VEGF plasma levels and percentage of VEGF immunostained area after repeated courses of DEX compared with controls (P < 0.001 and P = 0.001, respectively) or a single course (P = 0.028 and P = 0.002, respectively). Notably, repeated courses of DEX impaired normal increase in villous capillarization index compared with controls or a single course (P = 0.001 and P = 0.041, respectively).

CONCLUSION

Repeated antenatal courses of DEX compromised fetal and placental growth compared with a single course of DEX, and these effects were potentially mediated by altered maternal plasma levels and placental expression of VEGF with consequent decrease in placental vascularization. Because of continuing uncertainties, several key messages for clinicians are provided.

Miracle baby: managing extremely preterm birth in rural Uganda

Preterm birth is an important cause of neonatal morbidity and mortality globally. Uganda has one of the highest rates of preterm birth in East Africa but few resources to care for these infants. This case highlights the clinical course of an extremely premature infant born at 26 weeks gestation to a nulliparous 24-year-old woman. Her mother was involved in her care and taught the principles of kangaroo mother care. After initial problems establishing feeds she progressed well and was discharged in the fifth week of life. The case describes some of the low technology conservative and medical measures which can be used to care for neonates, such as antenatal steroids and kangaroo care. The use of antibiotics and aminophylline are also discussed. The approach to the common challenges faced by premature infants such as respiratory disease, sepsis and necrotising enterocolitis in a resource-poor environment are discussed.

[Prenatal corticosteroids: short-term and long-term effects of multiple courses. Literature review in 2013]

Prenatal corticosteroids administration is one of the major advances in obstetrics and neonatology for the prevention of preterm-birth related complications. However, concerns have been raised about its safety regarding neonatal growth and children development. Therefore, some obstetricians have restricted the use of corticosteroids to precisely defined indications. It remains some uncertainty regarding the choice of antenatal corticosteroids, the interval between injections, the timing of effectiveness and the maximum number of courses per pregnancy that is acceptable without causing complications among children. Thus, we performed a current literature review in 2013 regarding short- and long-term efficacy and safety in order to give clear recommendations to practitioners.

Delivery and performance of surfactant replacement therapies to treat pulmonary disorders

Lung surfactant is crucial for optimal pulmonary function throughout life. An absence or deficiency of surfactant can affect the surfactant pool leading to respiratory distress. Even if the coupling between surfactant dysfunction and the underlying disease is not always well understood, using exogenous surfactants as replacement is usually a standard therapeutic option in respiratory distress. Exogenous surfactants have been extensively studied in animal models and clinical trials. The present article provides an update on the evolution of surfactant therapy, types of surfactant treatment, and development of newer-generation surfactants. The differences in the performance between various surfactants are highlighted and advanced research that has been conducted so far in developing the optimal delivery of surfactant is discussed.

Effects of antenatal corticosteroids on the hypothalamic-pituitary-adrenocortical axis of the fetus and newborn: experimental findings and clinical considerations

The hypothalamic-pituitary-adrenocortical (HPA) axis is a major neuroendocrine pathway that modulates the stress response. The glucocorticoid, cortisol, is the principal end product of the HPA axis in humans and plays a fundamental role in maintaining homeostasis and in fetal maturation and development. Antenatal administration of synthetic glucocorticoids (GCs) accelerates fetal lung maturation and has significantly decreased neonatal mortality and morbidity in infants born before 34 weeks of gestation. Exposure to excess levels of endogenous GCs and exogenous GCs (betamethasone and dexamethasone) has been shown to alter the normal development trajectory. The development and regulation of the fetal HPA axis is discussed and the experimental animal evidence presented suggests long-term adverse consequences of altered HPA function. The clinical data in infants exposed to GCs also suggest altered HPA axis function over the short term. The longer-term consequences of antenatal GC exposure on HPA axis function and subtler neurodevelopmental outcomes including adaptation to stress, cognition, behavior, and the cardiovascular and immune responses are poorly understood. Emerging clinical strategies and interventions may help in the selection of mothers at risk for preterm delivery who would benefit from existing or future formulations of antenatal GCs with a reduction in the associated risk to the fetus and newborn. Detailed longitudinal long-term follow-up of those infants exposed to synthetic GCs are needed.

Effects of antenatal corticosteroids on neonatal outcomes in very-low-birth-weight preterm newborns: a 10-year retrospective study in a medical center

OBJECTIVE

To evaluate the effects on neonatal outcomes between very-low-birth-weight (VLBW) preterm newborns with and without maternal use of antenatal corticosteroids (ACS).

METHODS

We retrospectively reviewed medical records of VLBW premature infants who were admitted to Kaohsiung Medical University Hospital between 1999 and 2008. A total of 256 infants were enrolled in this study. A total of 174 neonates did not receive any ACS, and 82 neonates received ACS. A total of 37 neonates received one dose of ACS, and 45 neonates received more than one dose of ACS, referred to as "multiple-dose ACS." In addition, these 82 infants were divided to betamethasone group (n=8) and dexamethasone group (n=50) with 24 infants excluded because of inadequate information.

RESULTS

Neonates with multiple-dose ACS had lower incidence of surfactant use and lower rate of intubation than neonates without ACS. There were no differences in the occurrences of intraventricular hemorrhage, necrotizing enterocolitis, retinopathy of prematurity, sepsis, and chronic lung disease with one-dose vs. multiple-dose ACS and in the betamethasone group vs. the dexamethasone group.

CONCLUSIONS

ACS reduces the need for exogenous surfactant, and the need for endotracheal tube insertion at birth in VLBW premature infants.

Total serum bilirubin levels during the first 2 days of life and subsequent neonatal morbidity in very low birth weight infants: a retrospective review

To determine the relationship between total serum bilirubin (TSB) during the first 2 days of life and subsequent neonatal morbidity in very low birth weight (VLBW, less than 1500 g) infants. We performed a prospective study of 582 VLBW infants born between July 1, 2005 and December 31, 2009. TSB was measured in umbilical cord blood (UCB), at 24 and 48 h after birth. Demographic and clinical characteristics of infants in hospital were recorded. The interaction between TSB variables during the first 48 h of life and subsequent neonatal morbidity were assessed in logistic regression analyses adjusted for multiple risk factors. It was found that TSB in UCB was in a negative correlation with occurrence of respiratory distress syndrome (RDS) [OR 0.626, 95% confidence interval (95% CI): 0.446-0.879, p = 0.007], and there was also a negative correlation between TSB in UCB and occurrence of intraventricular hemorrhage (IVH) [OR 0.695, 95% CI 0.826-0.981, p = 0.020]. However, TSB in UCB positively correlated with hyperbilirubinemia [OR 2.471, 95% CI 1.326-3.551, p = 0.012], and TSB at 24 h after birth was also in a positive correlation with early onset sepsis (EOS) [OR 1.299, 95% CI 1.067-1.582, p = 0.011]. VLBW infants with low TSB levels in UCB were more likely to develop RDS and IVH, and those with low TSB levels in UCB were less likely to develop hyperbilirubinemia. Infants with high TSB levels at 24 h after birth were more likely to develop EOS. The protective effect of raised TSB in UCB with respect to RDS and IVH warrants further investigation.

Outcomes of extremely low birth weight infants with varying doses and intervals of antenatal steroid exposure

OBJECTIVE

To compare outcomes of extremely low birth weight (ELBW) infants exposed to no antenatal steroids (ANS); incomplete ANS and complete course of ANS at varying intervals prior to delivery.

METHODS

A retrospective review was performed on 169 ELBW infants with ANS exposure at varied dose-intervals. The odds of mortality, intraventricular hemorrhage (IVH) and bronchopulmonary dysplasia (BPD) were compared between Group 1, infants born without ANS exposure, Group 2, infants born after one dose of ANS, Group 3, infants born after two doses of ANS given within a week, and Group 4, infants born after two doses of ANS >7 days prior to delivery.

RESULTS

Mortality and IVH were significantly lower in Groups 3 (30% and 10%) and 4 (15% and 30%), compared to Groups 1 (56% and 69%) and 2 (56% and 38%). Increasing gestational age and exposure to complete course of ANS were significantly associated with decrease in mortality, BPD/mortality and IVH. Infants who received one dose of ANS had significantly lower incidence of severe IVH compared to infants without ANS exposure.

CONCLUSIONS

Beneficial impact of ANS on mortality and composite BPD/mortality is evident only after a complete course and persists even with its administration beyond a week from delivery.

Antenatal steroids in preterm labour for the prevention of neonatal deaths due to complications of preterm birth

BACKGROUND

In high-income countries, administration of antenatal steroids is standard care for women with anticipated preterm labour. However, although >1 million deaths due to preterm birth occur annually, antenatal steroids are not routine practice in low-income countries where most of these deaths occur.

OBJECTIVES

To review the evidence for and estimate the effect on cause-specific neonatal mortality of administration of antenatal steroids to women with anticipated preterm labour, with additional analysis for the effect in low- and middle-income countries.

METHODS

We conducted systematic reviews using standardized abstraction forms. Quality of evidence was assessed using an adapted GRADE approach. Existing meta-analyses were reviewed for relevance to low/middle-income countries, and new meta-analysis was performed.

RESULTS

We identified 44 studies, including 18 randomised control trials (RCTs) (14 in high-income countries) in a Cochrane meta-analysis, which suggested that antenatal steroids decrease neonatal mortality among preterm infants (<36 weeks gestation) by 31% [relative risk (RR) = 0.69; 95% confidence interval (CI) 0.58-0.81]. Our new meta-analysis of four RCTs from middle-income countries suggests 53% mortality reduction (RR = 0.47; 95% CI 0.35-0.64) and 37% morbidity reduction (RR = 0.63; 95% CI 0.49-0.81). Observational study mortality data were consistent. The control group in these equivalent studies was routine care (ventilation and, in many cases, surfactant). In low-income countries, many preterm babies currently receive little or no medical care. It is plausible that antenatal steroids may be of even greater effect when tested in these settings.

CONCLUSIONS

Based on high-grade evidence, antenatal steroid therapy is very effective in preventing neonatal mortality and morbidity, yet remains at low coverage in low/middle-income countries. If fully scaled up, this intervention could save up to 500 000 neonatal lives annually.

Evidence to support that spontaneous preterm labor is adaptive in nature: neonatal RDS is more common in "indicated" than in "spontaneous" preterm birth

OBJECTIVES

The onset of preterm labor has been proposed to have survival value and to be adaptive in nature. This hypothesis would predict that induced preterm birth may be associated with higher rates of complications than spontaneous preterm birth. The purpose of this study was to determine if there is a difference in the frequency of neonatal respiratory distress syndrome (RDS), the most common neonatal complication, according to the etiology of preterm birth (e.g., preterm labor [PTL], preterm PROM, or pregnancies which ended because of maternal-fetal indications).

STUDY DESIGN

The relationship between the occurrence of RDS and the obstetrical circumstances leading to preterm birth was examined in 257 consecutive singleton preterm births (gestational age: 24-32 weeks). Cases with major congenital anomalies were excluded. The study population was divided into two groups according to the cause of preterm birth: 1) preterm birth due to PTL with intact membranes or preterm PROM (spontaneous preterm birth group); and 2) preterm birth due to maternal or fetal indications (indicated preterm birth group).

RESULTS

1) RDS was diagnosed in 47% of cases; 2) RDS was more common in patients with indicated preterm birth than in those with spontaneous preterm birth group (58.1% vs. 38.4%, P=0.002); 3) Patients with indicated preterm birth had a significantly higher mean gestational age at birth, but lower mean birth weight, lower rate of histological chorioamnionitis and higher rates of cesarean delivery, 5 min Apgar score of <7, and umbilical arterial blood pH of <7.15 than those with spontaneous preterm birth (P<0.05 for each); 4) Antenatal corticosteroids were used in 73.4% of cases with indicated preterm birth and in 76.9% of those with spontaneous preterm birth; 5) Multivariate analysis demonstrated that indicated preterm birth was associated with an increased risk of RDS after adjusting for confounding variables (OR=2.29, 95% CI 1.22-4.29).

CONCLUSIONS

1) The rate of RDS is greater following "indicated" rather than spontaneous preterm birth; 2) This observation supports the view that spontaneous preterm labor is adaptive in nature.