Betamethasone dosing interval: 12 or 24 hours apart? A randomized, noninferiority open trial

Clinical Dilemma Involving Treatments for Very Low-Birth-Weight Infants and the Potential Risk of Necrotizing Enterocolitis: A Narrative Literature Review

Necrotizing enterocolitis (NEC) is a critical gastrointestinal emergency with substantial morbidity and mortality risks, especially for very low-birth-weight (VLBW) infants, and unclear multifactorial pathophysiology. Whether common treatments for VLBW infants increase the NEC risk remains controversial. Indomethacin (utilized for patent ductus arteriosus) offers benefits but is concerning because of its vasoconstrictive impact on NEC susceptibility. Similarly, corticosteroids used to treat bronchopulmonary dysplasia may increase vulnerability to NEC by compromising immunity and altering the mesenteric blood flow. Histamine-2 receptor blockers (used to treat gastric bleeding) may inadvertently promote NEC by affecting bacterial colonization and translocation. Doxapram (used to treat apnea) poses a risk of gastrointestinal disturbance via gastric acid hypersecretion and circulatory changes. Glycerin enemas aid meconium evacuation but disrupt microbial equilibrium and trigger stress-related effects associated with the NEC risk. Prolonged antibiotic use may unintentionally increase the NEC risk. Blood transfusions for anemia can promote NEC via interactions between the immune response and ischemia-reperfusion injury. Probiotics for NEC prevention are associated with concerns regarding sepsis and bacteremia. Amid conflicting evidence, this review unveils NEC risk factors related to treatments for VLBW infants, offers a comprehensive overview of the current research, and guides personalized management strategies, thereby elucidating this clinical dilemma.

The Effect of Betamethasone Dosing Interval on Perinatal Outcomes: 12 Hours or 24 Hours Apart

OBJECTIVE

Antenatal steroids are commonly used to stimulate fetal lung maturation, particularly in pregnancies at risk of early preterm labor. This study aimed to compare the effects of administering betamethasone at a 12- versus 24-hour interval on perinatal outcomes.

STUDY DESIGN

This retrospective study included 423 early preterm births from 26+0/7 to 33+6/7 weeks of gestation. Patients received betamethasone at either a 12- or 24-hour dosing interval.

RESULTS

When all patients in each group were evaluated together, there was no statistically significant difference between both groups for complications of prematurity, including respiratory distress syndrome (RDS). When the two groups were divided by gestational age (GA), the 32+0/7 to 33+6/7-week group that received betamethasone at a 24-hour interval had statistically lower 1- and 5-minute APGAR scores (p = 0.06 and p = 0.02, respectively). They also had a greater need for neonatal intensive care unit (NICU), NICU length of stay, RDS, and need for surfactant (p = 0.20, p = 0.09, p = 0.27, and p = 0.23, respectively) than did the infants at 32+0/7 to 33+6/7 weeks, who received betamethasone at a 12-hour interval. In the group with GA between 28+0/7 and 29+6/7 weeks, the 1-minute APGAR score was lower (p = 0.22), and the durations of hospital stay, and mechanical ventilation were longer (p = 0.048, p = 0.21, respectively) in the 24-hour interval group. No statistically significant difference was observed for all parameters in other GA groups.

CONCLUSION

A 12-hour dosing interval for betamethasone appears to be more appropriate, as it results in a reduction in some neonatal complications and provides a short dose interval.

KEY POINTS

· RDS is reduced when betamethasone is used 12 hours apart.. · When betamethasone is used 12 hours apart, the need for surfactant is reduced.. · The use of betamethasone 12 hours apart is advantageous with its short dose interval..

Prevention and Therapy of Preterm Birth. Guideline of the DGGG, OEGGG and SGGG (S2k Level, AWMF Registry Number 015/025, September 2022) - Part 2 with Recommendations on the Tertiary Prevention of Preterm Birth and on the Management of Preterm Premature Rupture of Membranes

Aim The revision of this guideline was coordinated by the German Society for Gynecology and Obstetrics (DGGG), the Austrian Society for Gynecology and Obstetrics (OEGGG) and the Swiss Society for Gynecology and Obstetrics (SGGG). The aim of the guideline is to improve the prediction, prevention and management of preterm birth based on evidence from the current literature, the experience of members of the guidelines commission, and the viewpoint of self-help organizations. Methods The members of the contributing professional societies and organizations developed recommendations and statements based on international literature. The recommendations and statements were presented and adopted using a formal process (structured consensus conferences with neutral moderation, written Delphi vote). Recommendations Part 2 of this short version of the guideline presents statements and recommendations on the tertiary prevention of preterm birth and the management of preterm premature rupture of membranes.

Different corticosteroids and regimens for accelerating fetal lung maturation for babies at risk of preterm birth

BACKGROUND

Despite the widespread use of antenatal corticosteroids to prevent respiratory distress syndrome (RDS) in preterm infants, there is currently no consensus as to the type of corticosteroid to use, dose, frequency, timing of use or the route of administration.  OBJECTIVES: To assess the effects on fetal and neonatal morbidity and mortality, on maternal morbidity and mortality, and on the child and adult in later life, of administering different types of corticosteroids (dexamethasone or betamethasone), or different corticosteroid dose regimens, including timing, frequency and mode of administration.

SEARCH METHODS

For this update, we searched Cochrane Pregnancy and Childbirth Group's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (9 May 2022) and reference lists of retrieved studies.

SELECTION CRITERIA

We included all identified published and unpublished randomised controlled trials or quasi-randomised controlled trials comparing any two corticosteroids (dexamethasone or betamethasone or any other corticosteroid that can cross the placenta), comparing different dose regimens (including frequency and timing of administration) in women at risk of preterm birth. We planned to exclude cross-over trials and cluster-randomised trials. We planned to include studies published as abstracts only along with studies published as full-text manuscripts.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed study eligibility, extracted data and assessed the risk of bias of included studies. Data were checked for accuracy. We assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We included 11 trials (2494 women and 2762 infants) in this update, all of which recruited women who were at increased risk of preterm birth or had a medical indication for preterm birth. All trials were conducted in high-income countries. Dexamethasone versus betamethasone Nine trials (2096 women and 2319 infants) compared dexamethasone versus betamethasone. All trials administered both drugs intramuscularly, and the total dose in the course was consistent (22.8 mg or 24 mg), but the regimen varied. We assessed one new study to have no serious risk of bias concerns for most outcomes, but other studies were at moderate (six trials) or high (two trials) risk of bias due to selection, detection and attrition bias. Our GRADE assessments ranged between high- and low-certainty, with downgrades due to risk of bias and imprecision.  Maternal outcomes The only maternal primary outcome reported was chorioamnionitis (death and puerperal sepsis were not reported). Although the rate of chorioamnionitis was lower with dexamethasone, we did not find conclusive evidence of a difference between the two drugs (risk ratio (RR) 0.71, 95% confidence interval (CI) 0.48 to 1.06; 1 trial, 1346 women; moderate-certainty evidence). The proportion of women experiencing maternal adverse effects of therapy was lower with dexamethasone; however, there was not conclusive evidence of a difference between interventions (RR 0.63, 95% CI 0.35 to 1.13; 2 trials, 1705 women; moderate-certainty evidence). Infant outcomes We are unsure whether the choice of drug makes a difference to the risk of any known death after randomisation, because the 95% CI was compatible with both appreciable benefit and harm with dexamethasone (RR 1.03, 95% CI 0.66 to 1.63; 5 trials, 2105 infants; moderate-certainty evidence). The choice of drug may make little or no difference to the risk of RDS (RR 1.06, 95% CI 0.91 to 1.22; 5 trials, 2105 infants; high-certainty evidence). While there may be little or no difference in the risk of intraventricular haemorrhage (IVH), there was substantial unexplained statistical heterogeneity in this result (average (a) RR 0.71, 95% CI 0.28 to 1.81; 4 trials, 1902 infants; I² = 62%; low-certainty evidence). We found no evidence of a difference between the two drugs for chronic lung disease (RR 0.92, 95% CI 0.64 to 1.34; 1 trial, 1509 infants; moderate-certainty evidence), and we are unsure of the effects on necrotising enterocolitis, because there were few events in the studies reporting this outcome (RR 5.08, 95% CI 0.25 to 105.15; 2 studies, 441 infants; low-certainty evidence). Longer-term child outcomes Only one trial consistently followed up children longer term, reporting  at two years' adjusted age. There is probably little or no difference between dexamethasone and betamethasone in the risk of neurodevelopmental disability at follow-up (RR 1.02, 95% CI 0.85 to 1.22; 2 trials, 1151 infants; moderate-certainty evidence). It is unclear whether the choice of drug makes a difference to the risk of visual impairment (RR 0.33, 95% CI 0.01 to 8.15; 1 trial, 1227 children; low-certainty evidence). There may be little or no difference between the drugs for hearing impairment (RR 1.16, 95% CI 0.63 to 2.16; 1 trial, 1227 children; moderate-certainty evidence), motor developmental delay (RR 0.89, 95% CI 0.66 to 1.20; 1 trial, 1166 children; moderate-certainty evidence) or intellectual impairment (RR 0.97, 95% CI 0.79 to 1.20; 1 trial, 1161 children; moderate-certainty evidence). However, the effect estimate for cerebral palsy is compatible with both an important increase in risk with dexamethasone, and no difference between interventions (RR 2.50, 95% CI 0.97 to 6.39; 1 trial, 1223 children; low-certainty evidence). No trials followed the children beyond early childhood. Comparisons of different preparations and regimens of corticosteroids We found three studies that included a comparison of a different regimen or preparation of either dexamethasone or betamethasone (oral dexamethasone 32 mg versus intramuscular dexamethasone 24 mg; betamethasone acetate plus phosphate versus betamethasone phosphate; 12-hourly betamethasone versus 24-hourly betamethasone). The certainty of the evidence for the main outcomes from all three studies was very low, due to  small sample size and  risk of bias. Therefore, we were limited in our ability to draw conclusions from any of these studies.

AUTHORS' CONCLUSIONS

Overall, it remains unclear whether there are important differences between dexamethasone and betamethasone, or between one regimen and another.  Most trials compared dexamethasone versus betamethasone. While for most infant and early childhood outcomes there may be no difference between these drugs, for several important outcomes for the mother, infant and child the evidence was inconclusive and did not rule out significant benefits or harms. The evidence on different antenatal corticosteroid regimens was sparse, and does not support the use of one particular corticosteroid regimen over another.

The use of antenatal corticosteroids for fetal maturation: clinical practice guideline by the WAPM-World Association of Perinatal Medicine and the PMF-Perinatal Medicine foundation

This practice guideline follows the mission of the World Association of Perinatal Medicine in collaboration with the Perinatal Medicine Foundation, bringing together groups and individuals throughout the world, with the goal of improving the use of antenatal corticosteroids (ACS) for fetal maturation. In fact, this document provides further guidance for healthcare practitioners on the appropriate use of ACS with the aim to increase the timely administration and avoid unnecessary or excessive use. Therefore, it is not intended to establish a legal standard of care. This document is based on consensus among perinatal experts throughout the world and serves as a guideline for use in clinical practice.

Antenatal Betamethasone Every 12 Hours in Imminent Preterm Labour

Background: Benefits of antenatal corticosteroids have been established for preterm infants who have received the full course. In imminent preterm labours there is no time to administer the second dose 24 h later. Objective: To determine whether the administration of two doses of betamethasone in a 12 h interval is equivalent to the effects of a full maturation. Methods: We performed a retrospective cohort study including preterm infants ≤34 weeks gestational age at birth and ≤1500 g, admitted to an NICU IIIC level in a tertiary hospital from 2015 to 2020. The population was divided into two cohorts: complete maturation (CM) (two doses of betamethasone 24 h apart), or advanced maturation (AM) (two doses of betamethasone 12 h apart). The primary outcomes were mortality or survival with severe morbidities. The presence of respiratory distress syndrome and other morbidities of prematurity were determined. These variables were analysed in the neonates under 28 weeks gestational age cohort. Neurodevelopment at 2 years was evaluated with the validated Ages and Stages Questionnaires^®, Third Edition (ASQ^®-3). Multiple regression analyses were performed and adjusted for confounding factors. Results: A total of 275 preterm neonates were included. Serious outcomes did not show differences between cohorts, no increased incidence of morbidity was found in AM. A lower percentage of hypotension during the first week (p = 0.04), a tendency towards lower maximum FiO₂ (p = 0.14) and to a shorter mechanical ventilation time (p = 0.14) were observed for the AM cohort. Similar results were found in the subgroup of neonates under 28 weeks gestational age. There were no differences in cerebral palsy or sensory deficits at 24 months of corrected age, although the AM cohort showed a trend towards better scores on the ASQ3 scale. Conclusions: Administration of betamethasone every 12 h showed similar results to the traditional pattern with respect to mortality and severe morbidities. No deleterious neurodevelopmental effects were found at 24 months of corrected age. Earlier administration of betamethasone at 12 h after the first dose would be an alternative in imminent preterm delivery. Further studies are needed to confirm these results.

Is there a benefit of antenatal corticosteroid when given < 48 h before delivery?

OBJECTIVE

We assessed the association between a short antenatal corticosteroid administration-to-birth interval and neonatal outcome.

STUDY DESIGN

A retrospective study was conducted between 2010 and 2020. Eligible cases were singleton preterm live-born neonates born between 24-0/7 and 33-6/7 weeks of gestation and were initiated an ACS course of betamethasone. We divided the first 48 h following the first ACS administration to four time intervals and compared each time interval to those born more than 48 h following ACS administration. The primary outcome was a composite of adverse neonatal outcome, including neonatal mortality or any major neonatal morbidity.

RESULTS

A total of 200 women gave birth less than 48 h from receiving the first betamethasone injection, and 172 women gave birth within 2-7 days (48-168 h) from ACS administration. Composite adverse neonatal outcome was higher for neonates born less than 12 h from initial ACS administration compared to neonates born 2-7 days from the first betamethasone injection (55.45% vs. 29.07%, OR 3.45 95% CI [2.02-5.89], p value < 0.0001). However, there was no difference in composite adverse neonatal outcomes between neonates born 12-48 h following ACS administration and those born after 2-7 days. That was also true after adjusting for confounders.

CONCLUSIONS

12-24 h following ACS administration may be sufficient in reducing the same risk of neonatal morbidities as > 48 h following ACS administration. It may raise the question regarding the utility of the second dose of ACS.

Administration of Antenatal Corticosteroids: Current State of Knowledge

The administration of a single course of corticosteroids before week 34 + 0 of gestation in cases with impending preterm birth is now standard procedure in obstetric care and firmly established in the guidelines of different countries. But despite the apparently convincing data, numerous aspects of this intervention have not yet been properly studied. It is still not clear which corticosteroid achieves the best results. There are very few studies on what constitutes an appropriate dose, circadian rhythms, the time frame in which corticosteroids are effective, and the balance between the risks and benefits of repeat administration. As the existing studies have rarely included patients before week 24 + 0 of gestation, we have very little information on the possible benefits of administering corticosteroids before this timepoint. If corticosteroids are administered antenatally after week 34 + 0 of gestation, the short-term benefit may be offset by the long-term adverse effect on psychomotor development. This present study summarizes the current state of knowledge regarding these issues.

Should the interval between doses of antenatal corticosteroids be shortened in certain cases? Factors predicting preterm delivery < 48 h from presentation

PURPOSE

Treatment with antenatal corticosteroids (ACS) to women at risk for preterm birth (PTB) is associated with a reduction in adverse neonatal outcomes. Obstetricians occasionally shorten the interval between the doses of steroids if delivery is predicted to occur before ACS are fully administered. In this study, we aimed to investigate predicting factors to identify patients that will deliver prematurely, less than 48 h from presentation.

METHODS

The computerized medical files of all PTBs (< 34 weeks) were reviewed. Maternal demographics, pregnancy and delivery characteristics were compared between PTB that occurred < 48 h vs. > 48 h from triage presentation.

RESULTS

In total, 494 PTB cases were included: 302 women in the study group (PTB < 48 h) and 192 women in the control group (PTB > 48 h). No significant differences were found in demographic characteristics between the groups. At presentation, the study group had higher rates of uterine contractions (p < 0.001) and cervical length < 25 mm (p < 0.001) as well as a higher rate of non-reassuring fetal (NRFHR) monitor (p < 0.001). In contrast, the control group presented with higher rates of preeclampsia (p = 0.003) and preterm premature rupture of membranes (p = 0.038). In multivariable analysis, all of the above factors remained significant after controlling for background confounders.

CONCLUSIONS

Various factors at presentation can predict delivery < 48 h. These factors can be used to predict patients to whom the ACS interval should be shortened. Future prospective studies should investigate the effect of this shortening on neonatal outcomes.

Dexamethasone versus betamethasone for preterm birth: a systematic review and network meta-analysis

OBJECTIVE

This study aimed to evaluate the comparative clinical effectiveness and safety of dexamethasone vs betamethasone for preterm birth.

DATA SOURCES

The sources searched were MEDLINE, EMBASE, Cochrane Library, LILACS, ClinicalTrials.gov, and International Clinical Trials Registry Platform without language restrictions until October 2019 in addition to the reference lists of included studies. Field experts were also contacted.

STUDY ELIGIBILITY CRITERIA

Randomized or quasi-randomized controlled trials comparing any corticosteroids against each other or against placebo at any dose for preterm birth were included in the study.

METHODS

Three researchers independently selected and extracted data and assessed the risk of bias of the included studies by using Early Review Organizing Software and Covidence software. Random-effects pairwise meta-analysis and Bayesian network meta-analysis were performed. The primary outcomes were chorioamnionitis, endometritis or puerperal sepsis, neonatal death, respiratory distress syndrome, and neurodevelopmental disability.

RESULTS

A total of 45 trials (11,227 women and 11,878 infants) were included in the study. No clinical or statistical difference was found between dexamethasone and betamethasone in neonatal death (odds ratio, 1.05; 95% confidence interval, 0.62-1.84; moderate-certainty evidence), neurodevelopmental disability (odds ratio, 1.03; 95% confidence interval, 0.80-1.33; moderate-certainty evidence), intraventricular hemorrhage (odds ratio, 1.04; 95% confidence interval, 0.56-1.78); low-certainty evidence), or birthweight (+5.29 g; 95% confidence interval, -49.79 to 58.97; high-certainty evidence). There was no statistically significant difference, but a potentially clinically important effect was found between dexamethasone and betamethasone in chorioamnionitis (odds ratio, 0.70; 95% confidence interval, 0.45-1.06; moderate-certainty evidence), fetal death (odds ratio, 0.81; 95% confidence interval, 0.24-2.41; low-certainty evidence), puerperal sepsis (odds ratio, 2.04; 95% confidence interval, 0.72-6.06; low-certainty evidence), and respiratory distress syndrome (odds ratio, 1.34; 95% confidence interval, 0.96-2.11; moderate-certainty evidence). Meta-regression, subgroup, and sensitivity analyses did not reveal important changes regarding the main analysis.

CONCLUSION

Corticosteroids have proven effective for most neonatal and child-relevant outcomes compared with placebo or no treatment for women at risk of preterm birth. No important difference was found on neonatal death, neurodevelopmental disability, intraventricular hemorrhage, and birthweight between corticosteroids, and there was no statistically significant difference, but a potentially important difference was found in chorioamnionitis, fetal death, endometritis or puerperal sepsis, and respiratory distress syndrome. Further research is warranted to improve the certainty of evidence and inform health policies.

Antenatal corticosteroids, maternal body mass index and infant morbidity within the ASTEROID trial

BACKGROUND

Antenatal corticosteroids (ACSs) administered to women before preterm birth improve neonatal health. Proportionately more women are obese or overweight in current obstetric populations than those who were included in the original trials of ACSs, and it remains uncertain if higher doses are required for such women.

AIM

Our aim was to assess the association between maternal body mass index (BMI) and infant morbidity after the administration of ACSs.

METHODS

In the secondary analysis of the ASTEROID trial cohort, women at risk of preterm birth at <34 weeks' gestation were randomised to betamethasone or dexamethasone. Infant outcomes were compared according to whether women were of normal weight (BMI < 25 kg/m² ), overweight (BMI 25-29.9 kg/m² ) or obese (BMI ≥ 30 kg/m² ).

RESULTS

Of 982 women with a singleton pregnancy and BMI data, 519 (52.9%) were of normal size, 241 (24.5%) were overweight and 222 (22.6%) were obese. Compared with infants born to women of normal weight, there was little or no difference in respiratory distress syndrome in infants born to women who were overweight (odds ratio (OR) = 0.92, 95% confidence interval (CI) 0.57, 1.49) or obese (OR = 1.44, 95% CI 0.90, 2.31). Similarly, there were no significant differences between infants born to women in the three BMI groups for other morbidities, including bronchopulmonary dysplasia, mechanical ventilation, intraventricular haemorrhage, retinopathy of prematurity, patent ductus arteriosus, necrotising enterocolitis, perinatal death or combined serious morbidity.

CONCLUSIONS

Maternal body size is not associated with infant morbidity after ACS exposure. Dose adjustment for women with higher BMI is not required.

Antenatal corticosteroids for accelerating fetal lung maturation for women at risk of preterm birth

BACKGROUND

Respiratory morbidity including respiratory distress syndrome (RDS) is a serious complication of preterm birth and the primary cause of early neonatal mortality and disability. Despite early evidence indicating a beneficial effect of antenatal corticosteroids on fetal lung maturation and widespread recommendations to use this treatment in women at risk of preterm delivery, some uncertainty remains about their effectiveness particularly with regard to their use in lower-resource settings, different gestational ages and high-risk obstetric groups such as women with hypertension or multiple pregnancies. This updated review (which supersedes an earlier review Crowley 1996) was first published in 2006 and subsequently updated in 2017.

OBJECTIVES

To assess the effects of administering a course of corticosteroids to women prior to anticipated preterm birth (before 37 weeks of pregnancy) on fetal and neonatal morbidity and mortality, maternal mortality and morbidity, and on the child in later life.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (3 September 2020), ClinicalTrials.gov, the databases that contribute to the WHO International Clinical Trials Registry Platform (ICTRP) (3 September 2020), and reference lists of the retrieved studies.

SELECTION CRITERIA

We considered all randomised controlled comparisons of antenatal corticosteroid administration with placebo, or with no treatment, given to women with a singleton or multiple pregnancy, prior to anticipated preterm delivery (elective, or following rupture of membranes or spontaneous labour), regardless of other co-morbidity, for inclusion in this review.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane Pregnancy and Childbirth methods for data collection and analysis. Two review authors independently assessed trials for inclusion, assessed risk of bias, evaluated trustworthiness based on predefined criteria developed by Cochrane Pregnancy and Childbirth, extracted data and checked them for accuracy, and assessed the certainty of the evidence using the GRADE approach. Primary outcomes included perinatal death, neonatal death, RDS, intraventricular haemorrhage (IVH), birthweight, developmental delay in childhood and maternal death.

MAIN RESULTS

We included 27 studies (11,272 randomised women and 11,925 neonates) from 20 countries. Ten trials (4422 randomised women) took place in lower- or middle-resource settings. We removed six trials from the analysis that were included in the previous version of the review; this review only includes trials that meet our pre-defined trustworthiness criteria. In 19 trials the women received a single course of steroids. In the remaining eight trials repeated courses may have been prescribed. Fifteen trials were judged to be at low risk of bias, two had a high risk of bias in two or more domains and we ten trials had a high risk of bias due to lack of blinding (placebo was not used in the control arm. Overall, the certainty of evidence was moderate to high, but it was downgraded for IVH due to indirectness; for developmental delay due to risk of bias and for maternal adverse outcomes (death, chorioamnionitis and endometritis) due to imprecision. Neonatal/child outcomes Antenatal corticosteroids reduce the risk of: - perinatal death (risk ratio (RR) 0.85, 95% confidence interval (CI) 0.77 to 0.93; 9833 infants; 14 studies; high-certainty evidence; 2.3% fewer, 95% CI 1.1% to 3.6% fewer), - neonatal death (RR 0.78, 95% CI 0.70 to 0.87; 10,609 infants; 22 studies; high-certainty evidence; 2.6% fewer, 95% CI 1.5% to 3.6% fewer), - respiratory distress syndrome (RR 0.71, 95% CI 0.65 to 0.78; 11,183 infants; studies = 26; high-certainty evidence; 4.3% fewer, 95% CI 3.2% to 5.2% fewer). Antenatal corticosteroids probably reduce the risk of IVH (RR 0.58, 95% CI 0.45 to 0.75; 8475 infants; 12 studies; moderate-certainty evidence; 1.4% fewer, 95% CI 0.8% to1.8% fewer), and probably have little to no effect on birthweight (mean difference (MD) -14.02 g, 95% CI -33.79 to 5.76; 9551 infants; 19 studies; high-certainty evidence). Antenatal corticosteroids probably lead to a reduction in developmental delay in childhood (RR 0.51, 95% CI 0.27 to 0.97; 600 children; 3 studies; moderate-certainty evidence; 3.8% fewer, 95% CI 0.2% to 5.7% fewer). Maternal outcomes Antenatal corticosteroids probably result in little to no difference in maternal death (RR 1.19, 95% CI 0.36 to 3.89; 6244 women; 6 studies; moderate-certainty evidence; 0.0% fewer, 95% CI 0.1% fewer to 0.5% more), chorioamnionitis (RR 0.86, 95% CI 0.69 to 1.08; 8374 women; 15 studies; moderate-certainty evidence; 0.5% fewer, 95% CI 1.1% fewer to 0.3% more), and endometritis (RR 1.14, 95% CI 0.82 to 1.58; 6764 women; 10 studies; moderate-certainty; 0.3% more, 95% CI 0.3% fewer to 1.1% more) The wide 95% CIs in all of these outcomes include possible benefit and possible harm.

AUTHORS' CONCLUSIONS

Evidence from this updated review supports the continued use of a single course of antenatal corticosteroids to accelerate fetal lung maturation in women at risk of preterm birth. Treatment with antenatal corticosteroids reduces the risk of perinatal death, neonatal death and RDS and probably reduces the risk of IVH. This evidence is robust, regardless of resource setting (high, middle or low). Further research should focus on variations in the treatment regimen, effectiveness of the intervention in specific understudied subgroups such as multiple pregnancies and other high-risk obstetric groups, and the risks and benefits in the very early or very late preterm periods. Additionally, outcomes from existing trials with follow-up into childhood and adulthood are needed in order to investigate any longer-term effects of antenatal corticosteroids. We encourage authors of previous studies to provide further information which may answer any remaining questions about the use of antenatal corticosteroids without the need for further randomised controlled trials. Individual patient data meta-analyses from published trials are likely to provide answers for most of the remaining clinical uncertainties.

Controversies in antenatal corticosteroid treatment

Antenatal corticosteroids are now established as one of the cornerstones of therapy in the prevention of neonatal morbidity and mortality prior to preterm birth. Although this practice is widely accepted, a significant number of controversies exist. This review explores the knowledge gaps regarding the use of antenatal corticosteroids in the preterm, late preterm and term populations. Furthermore, the role of antenatal corticosteroids in special populations, such as diabetes, multiple pregnancies and periviable gestations, where high-quality data from randomized controlled trials are lacking, is also considered.

Antenatal Corticosteroids for Fetal Lung Maturity - Too Much of a Good Thing?

BACKGROUND

Between 5-15% of babies are born prematurely worldwide, with preterm birth defined as delivery before 37 completed weeks of pregnancy (term is at 40 weeks of gestation). Women at risk of preterm birth receive antenatal corticosteroids as part of standard care to accelerate fetal lung maturation and thus improve neonatal outcomes in the event of delivery. As a consequence of this treatment, the entire fetal organ system is exposed to the administered corticosteroids. The implications of this exposure, particularly the long-term impacts on offspring health, are poorly understood.

AIMS

This review will consider the origins of antenatal corticosteroid treatment and variations in current clinical practices surrounding the treatment. The limitations in the evidence base supporting the use of antenatal corticosteroids and the evidence of potential harm to offspring are also summarised.

RESULTS

Little has been done to optimise the dose and formulation of antenatal corticosteroid treatment since the first clinical trial in 1972. International guidelines for the use of the treatment lack clarity regarding the recommended type of corticosteroid and the gestational window of treatment administration. Furthermore, clinical trials cited in the most recent Cochrane Review have limitations which should be taken into account when considering the use of antenatal corticosteroids in clinical practice. Lastly, there is limited evidence regarding the long-term effects on the different fetal organ systems exposed in utero, particularly when the timing of corticosteroid administration is sub-optimal.

CONCLUSION

Further investigations are urgently needed to determine the most safe and effective treatment regimen for antenatal corticosteroids, particularly regarding the type of corticosteroid and optimal gestational window of administration. A clear consensus on the use of this common treatment could maximise the benefits and minimise potential harms to offspring.

Prevention and Therapy of Preterm Birth. Guideline of the DGGG, OEGGG and SGGG (S2k Level, AWMF Registry Number 015/025, February 2019) - Part 2 with Recommendations on the Tertiary Prevention of Preterm Birth and the Management of Preterm Premature Rupture of Membranes

Aims This is an official guideline of the German Society for Gynecology and Obstetrics (DGGG), the Austrian Society for Gynecology and Obstetrics (ÖGGG) and the Swiss Society for Gynecology and Obstetrics (SGGG). The aim of this guideline is to improve the prediction, prevention and management of preterm birth based on evidence obtained from recently published scientific literature, the experience of the members of the guideline commission and the views of self-help groups. Methods The members of the participating medical societies and organizations developed Recommendations and Statements based on the international literature. The Recommendations and Statements were adopted following a formal consensus process (structured consensus conference with neutral moderation, voting done in writing using the Delphi method to achieve consensus). Recommendations Part 2 of this short version of the guideline presents Statements and Recommendations on the tertiary prevention of preterm birth and the management of preterm premature rupture of membranes.

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.

Antenatal Administration of Betamethasone Contributes to Intimal Thickening of the Rat Ductus Arteriosus

BACKGROUND

Antenatal betamethasone (BMZ) is a standard therapy for reducing respiratory distress syndrome in preterm infants. Recently, some reports have indicated that BMZ promotes ductus arteriosus (DA) closure. DA closure requires morphological remodeling; that is, intimal thickening (IT) formation; however, the role of BMZ in IT formation has not yet been reported. Methods and Results: First, DNA microarray analysis using smooth muscle cells (SMCs) of rat preterm DA on gestational day 20 (pDASMCs) stimulated with BMZ was performed. Among 58,717 probe sets, ADP-ribosyltransferase 3 (Art3) was markedly increased by BMZ stimulation. Quantitative reverse transcription polymerase chain reaction (RT-PCR) confirmed the BMZ-induced increase of Art3 in pDASMCs, but not in aortic SMCs. Immunocytochemistry showed that BMZ stimulation increased lamellipodia formation. BMZ significantly increased total paxillin protein expression and the ratio of phosphorylated to total paxillin. A scratch assay demonstrated that BMZ stimulation promoted pDASMC migration, which was attenuated byArt3-targeted siRNAs transfection. pDASMC proliferation was not promoted by BMZ, which was analyzed by a 5'-bromo-2'-deoxyuridine (BrdU) assay. Whether BMZ increased IT formation in vivo was examined. BMZ or saline was administered intravenously to maternal rats on gestational days 18 and 19, and DA tissues were obtained on gestational day 20. The ratio of IT to tunica media was significantly higher in the BMZ-treated group.

CONCLUSIONS

These data suggest that antenatal BMZ administration promotes DA IT through Art3-mediated DASMC migration.

N° 364 - La Corticothérapie Prénatale Pour Améliorer Les Issues Néonatales

OBJECTIF

Évaluer les avantages et les risques de la corticothérapie prénatale chez les femmes qui présentent un risque d'accouchement prématuré ou qui subissent une césarienne à terme avant début de travail, et formuler des recommandations visant l'amélioration des issues néonatales et des issues à long terme.

OPTIONS

Administrer ou ne pas administrer une corticothérapie prénatale aux femmes qui présentent un risque élevé d'accouchement prématuré ou qui subissent une césarienne avant travail à terme. RéSULTATS: Morbidité périnatale, notamment le syndrome de détresse respiratoire, l'hémorragie intraventriculaire, la dysplasie bronchopulmonaire, l'infection, l'hypoglycémie, ainsi que les troubles de la croissance somatique et cérébrale et du neurodéveloppement; mortalité périnatale; et morbidité maternelle, notamment l'infection et la suppression surrénalienne.

UTILISATEURS CIBLES

Fournisseurs de soins de maternité, notamment les sages-femmes, les médecins de famille et les obstétriciens.

POPULATION CIBLE

Femmes enceintes. ÉVIDENCE: Nous avons interrogé les bases de données Medline, PubMed et Embase ainsi que la Bibliothèque Cochrane, de leur création au mois de septembre 2017. Nous nous sommes servis de Medical Subjet Headings (MeSH) et de mots clés en lien avec la grossesse, la prématurité, les corticostéroïdes ainsi que la mortalité et la morbidité périnatales et néonatales. Nous avons également consulté les déclarations d'organismes professionnels tels que les National Institutes of Health, l'American College of Obstetricians and Gynecologists, la Society for Maternal-Fetal Medicine, le Royal College of Obstetricians and Gynaecologists et la Société canadienne de pédiatrie pour obtenir des références additionnelles. Les essais cliniques randomisés évaluant la corticothérapie prénatale menés sur des femmes enceintes et les revues systématiques antérieures sur le sujet étaient admissibles, tout comme les données venant de revues systématiques d'études non expérimentales (études de cohorte).

VALEURS

La présente opinion de comité a été révisée et approuvée par le Comité de médecine fœto-maternelle de la SOGC, et approuvée par le Conseil de la SOGC. AVANTAGES, INCONVéNIENTS ET COûTS: L'administration d'une corticothérapie prénatale dans les sept jours précédant l'accouchement réduit significativement la morbidité et la mortalité périnatales associées à la naissance prématurée survenant entre 24+0 et 34+6 semaines de grossesse. Si la corticothérapie prénatale est administrée plus de sept jours avant l'accouchement ou après 34+6 semaines de grossesse, les effets indésirables peuvent surpasser les avantages. Les données probantes sur l'impact à long terme de la corticothérapie prénatale sont rares. Par ailleurs, les effets neurodéveloppementaux néfastes potentiels de l'exposition répétée à la corticothérapie prénatale ou de l'administration de corticostéroïdes en période préterme tardive ou à terme n'ont pas été quantifiés. MIS-à-JOUR à LA DIRECTIVE: Une revue des données probantes sera menée cinq ans après la publication de la présente directive clinique afin d'évaluer si une mise à jour complète ou partielle s'impose. Si de nouvelles données probantes importantes sont publiées avant la fin de ces cinq ans, une mise à jour tenant compte des nouvelles connaissances et recommandations sera publiée.

COMMANDITAIRES

La présente directive clinique a été élaborée à l'aide de ressources fournies par la Société des obstétriciens et gynécologues du Canada et avec l'appui des Instituts de recherche en santé du Canada (APR-126338). MOTS CLéS: Corticothérapie prénatale, maturation fœtale, prématurité, période préterme tardive, césarienne avant travail DÉCLARATION SOMMAIRES: RECOMMANDATIONS: Considérations relatives à l'âge gestationnel.

Comparison between two doses of betamethasone administration with 12 hours vs. 24 hours intervals on prevention of respiratory distress syndrome: a randomised trial

The purpose of the present study was to compare the effect of a two-dose administration of betamethasone with 12 hours interval vs. 24 hours interval on neonatal respiratory distress syndrome (RDS). The study was performed as a randomised clinical trial on 201 pregnant women with a gestational age of 26-34 weeks. In one group 12 mg of betamethasone every 12 hours for two doses and in the other group 12 mg of betamethasone every 24 hours for two doses were prescribed intramuscularly. There were no significant differences between the two groups according to maternal age, parity, gravidity, BMI, neonatal sex, need to surfactant, NICU admission, NICU stay, neonatal death, neonatal sepsis and Apgar score at minutes 1 and 5, but the gestational age at the beginning of the study and delivery receiving complete course of betamethasone and neonatal weight were lower in 24 hours group. RDS, necrotising enterocolitis, intra-ventricular haemorrhage and chorioamnionitis were more in the 24 hours' group. Multiple regression analysis showed that RDS and IVH (p = .022, RR = 0.07, CI95% 0.006-0.96 and p = .013; RR = 0.9, CI95% 0.1-0.89, respectively) were more in the 24 hours group and neonatal death (p = .034, RR = 4.7, CI95% 1.07-16.2) and NEC (p = 0.038, RR = 2.5, CI95% 1.7-3.7), were more in the 12 hours group. In conclusion, it seems that 12 hours interval betamethasone therapy may be considered as an alternative treatment in the case of preterm labour for acceleration of lung maturity; however, it is suggested that more studies should be performed on this issue and various morbidities. IMPACT STATEMENT What is already known on this subject: Administration of a single course of corticosteroids in all women with a gestational age of 24-34 weeks of pregnancy who are at risk for preterm labour and delivery has been recommended. The accepted regimen by National Institutes of Health (NIH) is an injection of betamethasone for two doses with 24 hours interval. What do the results of this study add: Twelve hours interval betamethasone therapy may be considered as an alternative treatment in the cases of preterm labour for acceleration of lung maturity. What are the implications of these findings for clinical practice and/or further research: Prescription of two doses (complete regimen) is more important than the interval between two doses for obtaining the maximum effect in a preterm birth.

Antenatal corticosteroids for accelerating fetal lung maturation for women at risk of preterm birth

BACKGROUND

Respiratory morbidity including respiratory distress syndrome (RDS) is a serious complication of preterm birth and the primary cause of early neonatal mortality and disability. While researching the effects of the steroid dexamethasone on premature parturition in fetal sheep in 1969, Liggins found that there was some inflation of the lungs of lambs born at gestations at which the lungs would be expected to be airless. Liggins and Howie published the first randomised controlled trial in humans in 1972 and many others followed.

OBJECTIVES

To assess the effects of administering a course of corticosteroids to the mother prior to anticipated preterm birth on fetal and neonatal morbidity and mortality, maternal mortality and morbidity, and on the child in later life.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (17 February 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

We considered all randomised controlled comparisons of antenatal corticosteroid administration (betamethasone, dexamethasone, or hydrocortisone) with placebo, or with no treatment, given to women with a singleton or multiple pregnancy, prior to anticipated preterm delivery (elective, or following spontaneous labour), regardless of other co-morbidity, for inclusion in this review. Most women in this review received a single course of steroids; however, nine of the included trials allowed for women to have weekly repeats.

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

This update includes 30 studies (7774 women and 8158 infants). Most studies are of low or unclear risk for most bias domains. An assessment of high risk usually meant a trial had potential for performance bias due to lack of blinding. Two trials had low risks of bias for all risk of bias domains.Treatment with antenatal corticosteroids (compared with placebo or no treatment) is associated with a reduction in the most serious adverse outcomes related to prematurity, including: perinatal death (average risk ratio (RR) 0.72, 95% confidence interval (CI) 0.58 to 0.89; participants = 6729; studies = 15; Tau² = 0.05, I² = 34%; moderate-quality); neonatal death (RR 0.69, 95% CI 0.59 to 0.81; participants = 7188; studies = 22), RDS (average RR 0.66, 95% CI 0.56 to 0.77; participants = 7764; studies = 28; Tau² = 0.06, I² = 48%; moderate-quality); moderate/severe RDS (average RR 0.59, 95% CI 0.38 to 0.91; participants = 1686; studies = 6; Tau² = 0.14, I² = 52%); intraventricular haemorrhage (IVH) (average RR 0.55, 95% CI 0.40 to 0.76; participants = 6093; studies = 16; Tau² = 0.10, I² = 33%; moderate-quality), necrotising enterocolitis (RR 0.50, 95% CI 0.32 to 0.78; participants = 4702; studies = 10); need for mechanical ventilation (RR 0.68, 95% CI 0.56 to 0.84; participants = 1368; studies = 9); and systemic infections in the first 48 hours of life (RR 0.60, 95% CI 0.41 to 0.88; participants = 1753; studies = 8).There was no obvious benefit for: chronic lung disease (average RR 0.86, 95% CI 0.42 to 1.79; participants = 818; studies = 6; Tau² = 0.38 I² = 65%); mean birthweight (g) (MD -18.47, 95% CI -40.83 to 3.90; participants = 6182; studies = 16; moderate-quality); death in childhood (RR 0.68, 95% CI 0.36 to 1.27; participants = 1010; studies = 4); neurodevelopment delay in childhood (RR 0.64, 95% CI 0.14 to 2.98; participants = 82; studies = 1); or death into adulthood (RR 1.00, 95% CI 0.56 to 1.81; participants = 988; studies = 1).Treatment with antenatal corticosteroids does not increase the risk of chorioamnionitis (RR 0.83, 95% CI 0.66 to 1.06; participants = 5546; studies = 15; moderate-quality evidence) or endometritis (RR 1.20, 95% CI 0.87 to 1.63; participants = 4030; studies = 10; Tau² = 0.11, I² = 28%; moderate-quality). No increased risk in maternal death was observed. However, the data on maternal death is based on data from a single trial with two deaths; four other trials reporting maternal death had zero events (participants = 3392; studies = 5; moderate-quality).There is no definitive evidence to suggest that antenatal corticosteroids work differently in any pre-specified subgroups (singleton versus multiple pregnancy; membrane status; presence of hypertension) or for different study protocols (type of corticosteroid; single course or weekly repeats).GRADE outcomes were downgraded to moderate-quality. Downgrading decisions (for perinatal death, RDS, IVH, and mean birthweight) were due to limitations in study design or concerns regarding precision (chorioamnionitis, endometritis). Maternal death was downgraded for imprecision due to few events.

AUTHORS' CONCLUSIONS

Evidence from this update supports the continued use of a single course of antenatal corticosteroids to accelerate fetal lung maturation in women at risk of preterm birth. A single course of antenatal corticosteroids could be considered routine for preterm delivery. It is important to note that most of the evidence comes from high income countries and hospital settings; therefore, the results may not be applicable to low-resource settings with high rates of infections.There is little need for further trials of a single course of antenatal corticosteroids versus placebo in singleton pregnancies in higher income countries and hospital settings. However, data are sparse in lower income settings. There are also few data regarding risks and benefits of antenatal corticosteroids in multiple pregnancies and other high-risk obstetric groups. Further information is also required concerning the optimal dose-to-delivery interval, and the optimal corticosteroid to use.We encourage authors of previous studies to provide further information, which may answer any remaining questions about the use of antenatal corticosteroids in such pregnancies without the need for further randomised controlled trials. Individual patient data meta-analysis from published trials is likely to answer some of the evidence gaps. Follow-up studies into childhood and adulthood, particularly in the late preterm gestation and repeat courses groups, are needed. We have not examined the possible harmful effects of antenatal corticosteroids in low-resource settings in this review. It would be particularly relevant to explore this finding in adequately powered prospective trials.

Antenatal glucocorticoids: where are we after forty years?

Since their introduction more than forty years ago, antenatal glucocorticoids have become a cornerstone in the management of preterm birth and have been responsible for substantial reductions in neonatal mortality and morbidity. Clinical trials conducted over the past decade have shown that these benefits may be increased further through administration of repeat doses of antenatal glucocorticoids in women at ongoing risk of preterm and in those undergoing elective cesarean at term. At the same time, a growing body of experimental animal evidence and observational data in humans has linked fetal overexposure to maternal glucocorticoids with increased risk of cardiovascular, metabolic and other disorders in later life. Despite these concerns, and somewhat surprisingly, there has been little evidence to date from randomized trials of longer-term harm from clinical doses of synthetic glucocorticoids. However, with wider clinical application of antenatal glucocorticoid therapy there has been greater need to consider the potential for later adverse effects. This paper reviews current evidence for the short- and long-term health effects of antenatal glucocorticoids and discusses the apparent discrepancy between data from randomized clinical trials and other studies.

Antenatal steroids: can we optimize the dose?

PURPOSE OF REVIEW

The beneficial effects of antenatal steroids in women at risk of preterm birth are evident. A dose of 24 mg appears sufficient, but there are insufficient data to recommend betamethasone or dexamethasone, a single steroid dose, the optimal interval between doses and repeated courses, the gestational age at which treatment is beneficial and the long-term effects of steroid treatment. This review addresses these aspects of antenatal steroid treatment.

RECENT FINDINGS

Although the 12-h and 24-h dosing intervals are equivalent with respect to prevention of respiratory distress syndrome, the former enables the completion of treatment in 50% more neonates delivered prematurely. Reducing the single steroid dose in patients at risk for premature birth reduces the associated maternal side effects. An inverse relationship has been demonstrated between the number of corticosteroid courses and foetal growth. The reduced size of exposed foetuses has been attributed to birth at earlier gestational ages and decreased foetal growth. Evidence suggests that antenatal exposure to synthetic glucocorticoids in term-born children has long-lasting effects, which may have important implications in the recommendation of steroids before elective caesarean at term.

SUMMARY

The short-term and long-term effects of the dosage regimen on the pregnant mother and foetus remain unclear.

Efficacy of betamethasone on the fetal motion and biophysical profile and amniotic fluid index in preterm fetuses

The term ofpreterm birth is used to define the premature neonates considering pregnancy age. In less than 34 week pregnancies, corticosteroids are prescribed to promote embryos' lung maturity. The presents study aimed at evaluating effects of betamethasone injection on feeling embryo motion by mother and index and biophysical profile in preterm pregnancies. In a descriptive-analytical study, 40 pregnant women with the pregnancy age of 30-34 weeks were evaluated. Embryo motion and index and biophysical profile of the amniotic fluid were checked before prescription of double dosage of muscular betamethasone (12 mg) at a 24 h time interval. The injection was repeated for 24 and 48 h after the first injection. The resulted outcomes were compared with those results related to before betamethasone injection. In this study, there was statistically meaningful relationship between embryo motions before injection of betamethasone and 12 h after its injection (p = 0.03). Also, there was a significant relationship between embryo motions 24 and 48 h after injection of betamethasone (p = 0.001). In other words, the embryo motions decreased 12 h after injection of betamethasone. They were improved 48 h after betamethasone injection. But, index and biophysical profile results of amniotic fluid were left unchanged. Application of betamethasone leads to evident but transient decrease in embryo motions. Although motion element of index and biophysical profile of amniotic fluid which is one of the tests used in evaluating the embryo health is fixed and normal, it can be concluded that injection of betamethasone may not affect embryo health.

[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.

Different corticosteroids and regimens for accelerating fetal lung maturation for women at risk of preterm birth

BACKGROUND

Despite the widespread use of antenatal corticosteroids to prevent respiratory distress syndrome in preterm infants, there is currently no consensus as to the type of corticosteroid to use; nor the dose, frequency, timing of use or the route of administration.

OBJECTIVES

To assess the effects of different corticosteroid regimens for women at risk of preterm birth.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (13 February 2013).

SELECTION CRITERIA

All identified published and unpublished randomised controlled trials or quasi-randomised control trials comparing any two corticosteroids (dexamethasone or betamethasone or any other corticosteroid that can cross the placenta), comparing different dose regimens (including frequency and timing of administration) in women at risk of preterm birth were included. We planned to exclude cross-over trials and cluster-randomised trials. We included studies published as abstracts only along with studies published as full-text manuscripts

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility, extracted data and assessed the risk of bias of included studies. Data were checked for accuracy.

MAIN RESULTS

For this update, 12 trials (1557 women and 1661 infants) were included. Dexamethasone was associated with a reduced risk of intraventricular haemorrhage (IVH) compared with betamethasone (risk ratio (RR) 0.44, 95% confidence interval (CI) 0.21 to 0.92; four trials, 549 infants). No statistically significant differences were seen for other primary outcomes: respiratory distress syndrome (RDS) (RR 1.06, 95% CI 0.88 to 1.27; five trials, 753 infants) and perinatal death (neonatal death RR 1.41, 95% CI 0.54 to 3.67; four trials, 596 infants). Similarly, very few differences were seen for secondary outcomes such as rate of admission to the neonatal intensive care unit (NICU) although in one trial, those infants exposed to dexamethasone, compared with betamethasone, had a significantly shorter length of NICU admission (mean difference (MD) -0.91 days, 95% CI -1.77 to -0.05; 70 infants). Results for biophysical parameters were inconsistent, but mostly no clinically important differences were seen.Compared with intramuscular dexamethasone, oral dexamethasone significantly increased the incidence of neonatal sepsis (RR 8.48, 95% CI 1.11 to 64.93) in one trial of 183 infants. No statistically significant differences were seen for other outcomes reported.Apart from a reduced maternal postpartum length of stay for women who received betamethasone at 12-hourly intervals compared to 24-hourly intervals in one trial (MD -0.73 days, 95% CI -1.28 to -0.18; 215 women), no differences in maternal or neonatal outcomes were seen between the different betamethasone dosing intervals assessed. Similarly, no significant differences in outcomes were seen when betamethasone acetate and phosphate was compared with betamethasone phosphate in one trial.

AUTHORS' CONCLUSIONS

It remains unclear whether one corticosteroid (or one particular regimen) has advantages over another.Dexamethasone may have some benefits compared with betamethasone such as less IVH, and a shorter length of stay in the NICU. The intramuscular route may have advantages over the oral route for dexamethasone, as identified in one small trial. Apart from the suggestion that 12-hour dosing may be as effective as 24-hour dosing of betamethasone based on one small trial, few other conclusions about optimal antenatal corticosteroid regimens were able to be made. No long-term results were available except for a small subgroup of 18 month old children in one trial. Trials comparing the commonly used corticosteroids are most urgently needed, as are trials of dosages and other variations in treatment regimens.

Are we making a mountain out of a mole hill? A call to appropriate interpretation of clinical trials and population-based studies

The volume of scientific articles being published continues to grow. Simultaneously, the ease with which both patients and providers can access scholarly articles is also increasing. One potential benefit of easy accessibility is broader awareness of new evidence. However, with a large volume of literature, it is often difficult to thoroughly review each article. Therefore, busy clinicians and inquisitive patients may often read the conclusion as their take-away message. In this article, we provide an overview of a few challenging study designs that are at increased risk for over- or understating conclusions, potentially leading to changes in clinical practice.