A randomised controlled comparison of betamethasone with dexamethasone: effects on the antenatal fetal heart rate

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We included all identified published and unpublished randomised controlled trials or quasi-randomised controlled trials comparing any two corticosteroids (dexamethasone or betamethasone or any other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.

Physiological control of fetal heart rate variability during labour: Implications and controversies

The interpretation of fetal heart rate (FHR) patterns is the only available method to continuously monitor fetal wellbeing during labour. One of the most important yet contentious aspects of the FHR pattern is changes in FHR variability (FHRV). Some clinical studies suggest that loss of FHRV during labour is a sign of fetal compromise so this is reflected in practice guidelines. Surprisingly, there is little systematic evidence to support this observation. In this review we methodically dissect the potential pathways controlling FHRV during labour-like hypoxaemia. Before labour, FHRV is controlled by the combined activity of the parasympathetic and sympathetic nervous systems, in part regulated by a complex interplay between fetal sleep state and behaviour. By contrast, preclinical studies using multiple autonomic blockades have now shown that sympathetic neural control of FHRV was potently suppressed between periods of labour-like hypoxaemia, and thus, that the parasympathetic system is the sole neural regulator of FHRV once FHR decelerations are present during labour. We further discuss the pattern of changes in FHRV during progressive fetal compromise and highlight potential biochemical, behavioural and clinical factors that may regulate parasympathetic-mediated FHRV during labour. Further studies are needed to investigate the regulators of parasympathetic activity to better understand the dynamic changes in FHRV and their true utility during labour. This article is protected by copyright. All rights reserved.

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.

Glycemic control following two regimens of antenatal corticosteroids in mild gestational diabetes: a randomized controlled trial

PURPOSE

To compare 3 consecutive days of hyperglycemic response following antenatal dexamethasone regimens of 12-mg or 6-mg doses 12 hourly in diet-controlled gestational diabetes.

METHODS

A randomized controlled trial was carried out in a university hospital in Malaysia. Women with lifestyle-controlled gestational diabetes scheduled to receive clinically indicated antenatal corticosteroids (dexamethasone) were randomized to 12-mg 12 hourly for one day (2 × 12-mg) or 6-mg 12-hourly for two days (4 × 6-mg). 6-point (pre and 2-h postprandial) daily self-monitoring of capillary blood sugar profile for up to 3 consecutive days was started after the first dexamethasone injection. Hyperglycemia is defined as blood glucose pre-meal ≥ 5.3 or 2 h postprandial ≥ 6.7 mmol/L. The primary outcome was a number of hyperglycemic episodes in Day-1 (first 6 BSP points). A sample size of 30 per group (N = 60) was planned.

RESULTS

Median [interquartile range] hyperglycemic episodes 4 [2.5-5] vs. 4 [3-5] p = 0.3 in the first day, 3 [2-4] vs. 1 [0-3] p = 0.01 on the second day, 0 [0-1] vs. 0 [0-1] p = 0.6 on the third day and over the entire 3 trial days 7 [6-9] vs. 6 [4-8] p = 0.17 for 6-mg vs. 12-mg arms, respectively. 2/30 (7%) in each arm received an anti-glycemic agent during the 3-day trial period (capillary glucose exceeded 11 mmol/L). Mean birth weight (2.89 vs. 2.49 kg p < 0.01) and gestational age at delivery (37.7 vs. 36.6 weeks p = 0.03) were higher and median delivery blood loss (300 vs. 400 ml p = 0.02) was lower in the 12-mg arm; all other secondary outcomes were not significantly different.

CONCLUSION

In gestational diabetes, 2 × 12-mg could be preferred over 4 × 6-mg dexamethasone as hyperglycemic episodes were fewer on Day-2, fewer injections were needed and the regimen was completed sooner.

CLINICAL TRIAL REGISTRATION

http://www.isrctn.com/ISRCTN16613220 .

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.

Effect of maternal betamethasone administration on feto-placental vascular resistance in the mouse†

Antenatal corticosteroids are often administered to women at risk of preterm birth to accelerate fetal lung development; however, there is evidence that this treatment may adversely affect placental function in some fetuses. Our group has recently demonstrated that wave reflections in the umbilical artery (UA), measured using high-frequency ultrasound, are sensitive to placental vascular abnormalities. In the present study, we used this approach to investigate the effect of maternal administration of betamethasone, a clinically relevant corticosteroid, on the feto-placental vasculature of the mouse. Fetuses were assessed at embryonic day (E)15.5 and E17.5 in C57BL6/J mice. At both gestational ages, the UA diameter, UA blood flow, and the wave reflection coefficient were significantly elevated in the betamethasone-treated mice compared to vehicle-treated controls. These observations support the interpretation that placental vascular resistance dropped with betamethasone treatment to an extent that could not be explained by vasodilation of the UA alone. Consistent with clinical studies, the effect of betamethasone on UA end-diastolic velocity was heterogeneous. Our results suggest that UA wave reflections are more sensitive to acute changes in placental vascular resistance compared with the UA pulsatility index, and this technique may have clinical application to identify a favorable placental vascular response to fetal therapies such as antenatal corticosteroids, where the fetal heart rate is likely to vary.

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.

The fetal electrocardiogram to detect the effects of betamethasone on fetal heart rate variability

BACKGROUND

Betamethasone is widely used to enhance fetal lung maturation in case of threatened preterm birth. Antenatal corticosteroids are known to reduce fetal heart rate variability (fHRV) in the days following administration. Since decreased fHRV is a marker for fetal distress, this transient decrease of fHRV can cause unnecessary medical intervention.

AIM

To describe the effect of betamethasone on fHRV, by applying spectral analysis on non-invasive fetal electrocardiogram (fECG) recordings.

STUDY DESIGN

Secondary analysis of a prospective cohort study.

SUBJECTS

Women with a singleton pregnancy, at risk for preterm delivery and receiving betamethasone, admitted to the obstetric high care unit in the period from March 2013 until July 2016.

OUTCOME MEASURES

The primary outcome measure was fHRV in both time- and frequency-domain. Secondary outcome measures included basal fetal heart rate (fHR) and fHR variance. FHRV parameters were then calculated separately for the quiet and active state.

RESULTS

Following 68 inclusions, 22 patients remained with complete series of measurements and sufficient data quality. FHRV parameters and fHR showed a decrease on day 2 compared to day 1, significant for short-term variability and high-frequency power. Similar results were found when analyzing for separate behavioral states. The number of segments in quiet state increased during days 1 and 2. Normalized values showed no difference for all behavioral states.

CONCLUSION

FHRV decreases on day 2 after betamethasone administration, while periods of fetal quiescence increase. No changes were found in the normalized values, indicating that the influence of autonomic modulation is minor. Clinical trial registration number NL43294.015.13.

Longitudinal progression of fetal short-term variation and average acceleration and deceleration capacity after antenatal maternal betamethasone application

OBJECTIVE

To analyze the effect of maternal betamethasone given for fetal lung maturation on fetal short-term variation (STV) and average acceleration and deceleration capacity (AAC/ADC). Both of these factors are calculated by phase-rectified signal averaging (PRSA) and represent new parameters to assess the fetal autonomic nervous system.

STUDY DESIGN

A longitudinal prospective study including 26 pregnant women at risk for preterm delivery was performed. Two injections of 12mg betamethasone were administered intramuscularly at a 24h interval for lung maturation. Cardiotocography recordings were performed at defined time intervals: day 0 (before the first injection) and days 1, 2, 4 after the first corticosteroid administration. AAC/ADC and STV were calculated.

RESULTS

An increase of all parameters (STV, AAC and ADC) was documented between day 0 and day 1. Between day 1 and day 2, all three indices were significantly reduced (p<0.05). STV declined by 19.8%, AAC by 10.1% and ADC by 14.8%. A normalization of these values was seen after 96h.

CONCLUSION

Similar to STV, AAC/ADC shows significant changes after maternal betamethasone administration. The corticosteroid-induced transient decrease of the levels needs to be taken into account in the assessment of the fetal status to avoid misinterpretation of these parameters.

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.

Dexamethasone effect on heart rate variability in preterm infants on mechanical ventilation

BACKGROUND

Dexamethasone is administered to some preterm infants with chronic lung disease to facilitate weaning from mechanical ventilation. Heart rate characteristics (HRC), including heart rate variability (HRV), may be impacted by glucocorticoids and may predict extubation readiness. A commercially available monitor developed for sepsis detection continuously calculates HRV and an HRC index, which are inversely related.

OBJECTIVES

Determine the impact of dexamethasone on HRV and the HRC index, in relation to extubation success.

METHODS

We identified 109 preterm infants who received dexamethasone while on mechanical ventilation and had HRC index monitoring data available. Average hourly HRV and HRC index were compared the day before and the day after initiation of dexamethasone in three groups: infants who remained on mechanical ventilation, those who were successfully extubated, and those who were extubated and required reintubation in < 3 days.

RESULTS

There was a significant increase in HRV and decrease in the HRC index the day after dexamethasone was started (HRV 16.2±0.5 vs 27.6±1.1 ms; HRC index 1.51±0.11 vs. 0.79±0.06 mean SE, p < 0.001). The 63 infants who were extubated within a day of starting dexamethasone had significantly higher HRV compared to those who remained on mechanical ventilation. There was no difference in HRV or its change with dexamethasone in the 45 infants who remained successfully extubated compared to the 18 infants who required reintubation within 3 days.

CONCLUSION

Dexamethasone improves HRV and lowers the HRC index in preterm infants with chronic lung disease on mechanical ventilation.

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.

Does the anti-hypertensive drug clonidine affect the short-term variation in CTG recordings?

BACKGROUND

Cardiotocographic (CTG) recordings of the fetal heart remain standard obstetric practice among hypertensive women. Changes in the short-term variation (STV) in the fetal heart are often attributed to the effect of anti-hypertensive medications, regardless of the fact that this principle has never been validated.

AIM

To assess the STV of CTG recordings pre- and post- the anti-hypertensive medication, clonidine.

METHODS

Forty hypertensive pregnant women, already receiving the anti-hypertensive clonidine, were recruited. The CTGs were conducted pre- and post-dose administration. The CTGs were assessed by the Sonicaid Team® automated CTG analysis (Oxford Instruments, UK) to avoid CTG assessor bias. Baseline fetal heart rate (FHR) (delta change from pre- and post-dose) and STV were compared using spss v.14® utilising Student t-tests.

RESULTS

No statistical difference was found in the pre- and post-baseline FHRs (P = 0.48). The mean delta baseline heart rate before and after drug administration was -0.54 bpm. The STV of the CTGs recorded pre- and post-clonidine dose was also not affected by administration of the drug (P = 0.34). The mean delta STV before and after drug administration was 0.39 ms. Two women received betamethasone 12 mg intramuscularly within the 12-h period prior to CTG recordings to enhance fetal lung maturity. The mean STV for the fetuses of these women pre-drug was 4.8 ms and 13.2 ms post-administration. This was the largest delta seen in all STVs recorded in this dataset.

CONCLUSION

The anti-hypertensive drug clonidine does not alter baseline FHRs or affect the STV of the FHR in hypertensive pregnant women.

The effect of antenatal steroid treatment on fetal autonomic heart rate regulation revealed by fetal magnetocardiography (fMCG)

BACKGROUND

Steroid administration to accelerate fetal lung maturation reduces neonatal morbidity and mortality in the case of preterm delivery. Behavioral observations suggest effects on fetal cardiovascular regulation.

AIM

We hypothesize that beat to beat heart rate variability (fHRV) derived from fetal magnetocardiography (fMCG) will reveal a direct, acute steroidal effect on fetal autonomic heart rate regulation.

SUBJECTS

Eight patients between 29 and 34 weeks of gestation at risk for preterm birth who were treated with betamethasone (2x12 mg within 24 h).

STUDY DESIGN

Subjects were studied prior to the first and within 6 h after the second administration. Continuous fMCG was recorded with a 31-channel-SQUID biomagnetometer. Each dataset was processed by subtracting maternal cardiac artefacts and determining the time instants of the fetal heart beats. fHRV analysis was applied to periods of fetal quiescence of 4 min length.

OUTCOME MEASURES

We compared fHRV prior versus post steroid administration.

RESULTS

Steroid exposure reduced all parameters of overall fHRV significantly. The fHRV parameters representing short term variability remained unaffected. Mean fetal heart rate significantly decreased. The complexity of the heart rate patterns increased.

CONCLUSION

Our results suggest an acute shift in the sympatho-vagal balance of fetuses exposed to betamethasone in utero toward sympathetic suppression.

Oxidative stress after antenatal betamethasone: acute downregulation of glutathione peroxidase-3

BACKGROUND

Human and experimental data show that antenatal exposure to glucocorticoids (GC) temporarily reduces fetal well-being and impairs the fetal response to hypoxemia.

AIMS

We tested the hypothesis that antenatal betamethasone provokes transient oxidative stress, which may be triggered directly by the GC or indirectly by metabolic signals such as increased glucose and free fatty acid (FFA) concentrations.

STUDY DESIGN

Prospective (single center, 18 months) cohort study in newborns <34 weeks gestational age at birth.

METHODS

We studied 105 newborns and measured oxidative damage to lipids [malondialdehyde (MDA)] and proteins (protein carbonyls), as well as glutathione peroxidase-3 (GPx3), an important antioxidant enzyme, in umbilical vein (UV) plasma. In addition, we measured umbilical artery and UV blood gases, and metabolic indices (plasma glucose, FFA and insulin) in UV.

RESULTS

MDA but not protein carbonyl concentrations was inversely related to time elapsed since the first or last betamethasone administration (p=0.006); MDA remained elevated by 69-96% for at least 72 h after the last betamethasone. By contrast, GPx3 concentrations were repressed in newborns who received betamethasone < or =24h before birth. GPx3 and MDA concentrations were correlated (r=-0.38, p<0.001). Labor, GA, sex, size at birth, blood gases or metabolic indices did not explain the effects of betamethasone on MDA and GPx3.

CONCLUSIONS

Antenatal GC elicit a rapid suppression of the GPx3 antioxidant defense system which may contribute to a longer-lasting but also transient rise in lipid oxidative damage.

Antenatal corticosteroid therapy: short-term effects on fetal behaviour and haemodynamics

Antenatal corticosteroid therapy to enhance fetal lung maturity in threatened preterm delivery has a number of non-pulmonary side-effects, both beneficial and undesirable. This review focuses on the short-term (transient) effects of betamethasone and dexamethasone on aspects of fetal circulation and behaviour which are used clinically as markers of fetal well-being. We summarise the effects observed, discuss the proposed underlying mechanisms, and emphasise the consequences for clinical decision-making. Recommendations are given to optimise medical care and to minimise the risk of unwarranted iatrogenic preterm delivery.

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 or 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 STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (January 2008).

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials of antenatal corticosteroid regimens in women at risk of preterm birth.

DATA COLLECTION AND ANALYSIS

Two authors assessed trial quality and extracted the data independently.

MAIN RESULTS

Ten trials (1089 women and 1161 infants) were included. Dexamethasone decreased the incidence of intraventricular haemorrhage 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 including respiratory distress syndrome, bronchopulmonary dysplasia, severe intraventricular haemorrhage, periventricular leukomalacia, perinatal death, or mean birthweight. Results for biophysical parameters were inconsistent, but mostly no important differences were seen for these, or any other secondary outcome except for neonatal intensive care unit (NICU) admission. In one trial of 105 infants, significantly more infants in the dexamethasone group were admitted to NICU compared with the betamethasone group (RR 3.83, 95% CI 1.24 to 11.87).Oral dexamethasone compared with intramuscular dexamethasone 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.In one small trial of 69 infants comparing betamethasone acetate and phosphate with betamethasone phosphate no differences were seen for any of the outcomes reported.

AUTHORS' CONCLUSIONS

Dexamethasone may have some benefits compared with betamethasone such as less intraventricular haemorrhage, although perhaps a higher rate of NICU admission (seen in only one trial). Apart from a suggestion from another small trial that the intramuscular route may have advantages over an oral route for dexamethasone, few other conclusions about optimal antenatal corticosteroid regimens were able to be made. Trials of commonly used corticosteroids are most urgently needed, followed by trials of dosages and other variations in regimens.

Maternal glucose levels after dexamethasone for fetal lung development in twin vs singleton pregnancies

OBJECTIVE

Betamethasone administration in singleton pregnancies causes maternal hyperglycemia. With the increased risk of glucose intolerance in twin pregnancies, we sought to determine whether maternal hyperglycemia after dexamethasone administration is different in twin vs singleton pregnancies.

STUDY DESIGN

Patients with singleton or twin pregnancies admitted between 24 and 34 weeks' gestation with diagnoses requiring steroid administration were approached. Exclusion criteria included diabetes, abnormal glucose tolerance test, infection, or medications known to interfere with glucose metabolism. Patients were NPO for 24 hours and received dexamethasone per protocol. Maternal glucose levels were checked at baseline and then at specified intervals after the initial dose; appropriate statistical analysis was performed.

RESULTS

Ten singleton and 9 twin gestations were enrolled. There were no differences in mean maternal or gestational ages. Mean glucose levels were significantly higher in the twin group at 4 hours (114 mg/dL vs 95.6 mg/dL), 8 hours (121.4 mg/dL vs 90.9 mg/dL), and 24 hours (116 mg/dL vs 81 mg/dL) (P < .01 for all).

CONCLUSION

Twin pregnancies had higher mean glucose values than singleton pregnancies in the first 24 hours after dexamethasone administration.

Glucocorticoid-associated Bradycardia

BACKGROUND

Glucocorticoids are known to cause several side-effects. This retrospective study addresses the relation of glucocorticoid therapy and heart rate. Patient charts of 61 children, treated with (the equivalent of) 1 to 5 mg/kg/d prednisone, were analyzed.

OBSERVATIONS

Heart rate decreased by 31 (95% CI=23-39) beats/min 72 hours after start treatment, and 63.9% of the children developed at least once a pulse rate <2.5th percentile for age during the first 88 hours after start of treatment. None of the children developed symptoms of reduced cardiac output.

CONCLUSION

A reduction in heart rate sometimes leading to sinus bradycardia may be a common early side-effect of glucocorticoid treatment in children.

Corticosteroids in perinatal medicine: how to improve outcomes without affecting the developing brain?

Antenatal glucocorticoid therapy remains one of the most striking successes in the perinatal management of complicated pregnancies that result in premature birth. The anti-inflammatory and maturative properties of fluorocorticoids are such that all women at risk of preterm delivery before 34weeks gestation should be treated. Betamethasone is preferred to dexamethasone and no more than two courses, 2weeks apart, should be given until the evidence from further controlled trials on repeated doses becomes available. In particular, the early use of postnatal dexamethasone should be avoided in preterm infants because of the deleterious effects on neurological development, including not only cerebral palsy but also cognitive function and psychiatric-related behavior. Treatment with other steroids should be restricted to the context of randomized controlled trials.

Intrapartum fetal monitoring today

The literature on intrapartum fetal monitoring is reviewed emphasizing the pathophysiology, and current practice guidelines are discussed. FHR monitoring, ancillary tests, and investigational modalities are considered.

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

BACKGROUND

Respiratory distress syndrome (RDS) is a serious complication of preterm birth and the primary cause of early neonatal mortality and disability.

OBJECTIVES

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

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (30 October 2005).

SELECTION CRITERIA

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, expected to deliver preterm as a result of either spontaneous preterm labour, preterm prelabour rupture of the membranes or elective preterm delivery.

DATA COLLECTION AND ANALYSIS

Two review authors assessed trial quality and extracted data independently.

MAIN RESULTS

Twenty-one studies (3885 women and 4269 infants) are included. Treatment with antenatal corticosteroids does not increase risk to the mother of death, chorioamnionitis or puerperal sepsis. Treatment with antenatal corticosteroids is associated with an overall reduction in neonatal death (relative risk (RR) 0.69, 95% confidence interval (CI) 0.58 to 0.81, 18 studies, 3956 infants), RDS (RR 0.66, 95% CI 0.59 to 0.73, 21 studies, 4038 infants), cerebroventricular haemorrhage (RR 0.54, 95% CI 0.43 to 0.69, 13 studies, 2872 infants), necrotising enterocolitis (RR 0.46, 95% CI 0.29 to 0.74, eight studies, 1675 infants), respiratory support, intensive care admissions (RR 0.80, 95% CI 0.65 to 0.99, two studies, 277 infants) and systemic infections in the first 48 hours of life (RR 0.56, 95% CI 0.38 to 0.85, five studies, 1319 infants). Antenatal corticosteroid use is effective in women with premature rupture of membranes and pregnancy related hypertension syndromes.

AUTHORS' CONCLUSIONS

The evidence from this new review 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 should be considered routine for preterm delivery with few exceptions. Further information is required concerning optimal dose to delivery interval, optimal corticosteroid to use, effects in multiple pregnancies, and to confirm the long-term effects into adulthood.

Integrated monitoring of fetal growth restriction by computerized cardiotocography and Doppler flow velocimetry

OBJECTIVE

To investigate the correlations between Doppler flow velocimetry and computerized cardiotocography (cCTG) in fetal growth restriction.

STUDY DESIGN

Fifty growth-restricted foetuses with abdominal circumference below the 10th percentile and no major abnormalities were studied. A total of 186 cCTG tracings (at least two per patient) analysed using the HP2CTG system were compared with the corresponding umbilical artery pulsatility index (PI), the PI ratio of umbilical artery to middle cerebral artery, and the ductus venosus systolic/atrial ratio.

RESULTS

Worsening in umbilical artery Doppler velocimetry parameters was associated with a significant reduction of short- and long-term variability indices and accelerations. When end-diastolic umbilical artery flow was preserved, a reversed ratio between umbilical artery and middle cerebral artery PIs was not correlated with a worsening of cCTG parameters; in the presence of umbilical artery absent or reversed flow, ductus venosus Doppler velocimetry abnormalities were correlated with a significant reduction of variability. When end-diastolic umbilical artery flow was preserved, there was a progressive increase in variability indices and accelerations with advancing gestational age. In the more compromised fetuses this "maturation" process of cCTG patterns was not found.

CONCLUSION

There is a strict correlation between Doppler velocimetry abnormalities and cCTG parameter deterioration, in particular between ductus venosus and variability.

Antenatal corticosteroid therapy: a comparative study of dexamethasone and betamethasone effects on fetal Doppler flow velocity waveforms

OBJECTIVE

To compare the effects of antenatal administration of dexamethasone and betamethasone, used in two different regimens, on fetal Doppler flow velocities.

STUDY DESIGN

Sixty-seven women at risk for preterm delivery received course of corticosteroids by means of a computer-generated randomization table. The Doppler examination of the pulsatility index (PI) of the umbilical artery (UA), the middle cerebral artery (MCA) and the middle cerebral artery/umbilical artery PI ratio (MCA PI/UA PI) were performed before treatment, 24 and 72 h after the first dose of corticosteroids. The SAS system was used to perform statistical analysis.

RESULTS

No significant change was observed in UA PI through dexamethasone therapy. In MCA there was a significant decrease in PI at 72 h (2+/-0.43 before and 1.68+/-0.31 after, p=0.0001). Similarly a significant decrease in MCA PI/UA PI ratio was noted (2.09+/-0.51 before and 1.83+/-0.4 after, p=0.0137). No significant changes were observed in UA PI, MCA PI and MCA PI/UA PI ratio during betamethasone treatment.

CONCLUSIONS

Our results indicate significant decrease in fetal middle cerebral artery impedance at 72 h after maternal administration of the first dose of dexamethasone. Effects of dexamethasone on fetal brain warrants further research.

Short-term (0-48 h) effects of maternal betamethasone administration on fetal heart rate and its variability

The short-term (0-48 h) effects of maternal betamethasone administration on computerized fetal heart rate (FHR) parameters were studied in 36 pregnancies at increased risk for preterm delivery. FHR was recorded for 90 min immediately before the start of betamethasone treatment and again at 6-h intervals during the next 48 h. Multiple linear regression models were used to assess the possible effects on FHR parameters of gestational age, time of day, clinical indication for treatment, and use of tocolytic drugs. Within 12 h after the start of treatment, significant increases occurred in FHR accelerations, and short- and long-term FHR variability (36%, 28%, and 22%, respectively), whereas basal FHR showed a 5% decrease. FHR variability was decreased by 10% at 42-48 h. The observed changes were more pronounced in older (29-33 wk of gestation) compared with younger fetuses (25-28 wk of gestation). Decelerations occurred only in 4 out of 11 compromised fetuses during betamethasone therapy. We conclude that there are significant changes in FHR parameters during the first 48 h after betamethasone administration. These changes are transient in normal fetuses. However, the compromised fetus may be adversely affected by betamethasone.

[Antenatal corticosteroids: benefits and risks]

A favorable benefit-to-risk ratio is well established for a single dose of antenatal corticosteroids in women at risk of preterm delivery. The efficacy is real with an important decrease of mortality and morbidity. No adverse effects were described after one course. Possible beneficial effects of repeated courses include lower rates of RDS and a decrease in oxygen use, whereas an increasing body of evidence raises the concern of multiple short and long term adverse consequences, principally neurological. It seems rational to prescribe one course of corticosteroids. The indication for a second course should be discussed but multiples courses of this treatment should not be prescribed. We prefer betamethasone over dexamethasone because of the better side profile. Further work is needed to understand the long-term effects of this treatment.

Decreased fetal movements: background, assessment, and clinical management

A reduction or cessation of fetal movements (FMs) is frequently reported by pregnant women and causes concern and anxiety. However, the clinical significance of a history of reduced FMs remains unclear, and the assessment and management of these pregnancies is controversial. This article is a review of the literature on decreased FMs found in medline and the cochrane library using the search phrases: decreased FMs, perinatal outcome, FM monitoring, and fetal assessment. Formal counting of FMs by the pregnant woman could possibly identify the fetuses, which are at risk of compromise, thus allowing for appropriate action. However, the benefit of this intervention has not been definitely proven. Cardiotocography, umbilical/uterine artery Doppler velocimetry, and ultrasonography have been used for antepartum fetal assessment in pregnancies with decreased FMs, but the evidence of a clinical benefit is limited. The effects of fetal assessment with vibroacoustic stimulation and biophysical profile are unknown and should be further evaluated. Present recommendations on the management of pregnancies with decreased FMs are based on limited and inconsistent scientific evidence. There is a need for further well-designed studies in order to provide evidence-based guidelines in the future.

The fetal cardiovascular response to antenatal steroids in severe early-onset intrauterine growth restriction

OBJECTIVE

Our aim was to study the hemodynamic effects of betamethasone on fetuses with intrauterine growth restriction (IUGR) with absent or reversed end-diastolic (ARED) umbilical artery flow.

STUDY DESIGN

Color/pulsed Doppler waveforms were obtained before and after intramuscular injections of betamethasone in 19 consecutive fetuses with IUGR/ARED and 6 control fetuses. Peak velocities and pulsatility index (PI) values were obtained from the umbilical (UA) and middle cerebral (MCA) arteries and intrahepatic umbilical vein (UV).

RESULTS

Ten ARED fetuses developed transient positive umbilical end-diastolic flow after steroids, whereas nine fetuses showed persistent ARED. The persistent ARED subgroup demonstrated increased UA and UV peak velocities after steroids, which may indicate fetal hypertension. Fetal death (n=2) and severe acidosis (n=2) were confined to the subgroup with persistent ARED.

CONCLUSION

Preterm IUGR/ARED fetuses exhibit divergent cardiovascular responses to prenatal steroids. Intensive Doppler-based fetal monitoring may identify a subset of fetuses prone to decompensation after maternal steroid administration.

Antenatal corticosteroid therapy: benefits and risks

Antenatal glucocorticoid therapy remains one the most striking successes in perinatal management of complicated pregnancies leading to premature birth. All women at risk of preterm delivery before 34 weeks gestation should be treated, given the anti-inflammatory and maturative properties of fluorocorticoids. Betamethasone is preferred to dexamethasone and no more than two courses, two weeks apart, should be given, until the evidence from further controlled trials on repeated doses becomes available.

The effects of antenatal betamethasone administration on fetal heart rate and behaviour depend on gestational age

OBJECTIVE

We previously reported decreases in fetal heart rate (FHR) variability and body and breathing movements after maternal betamethasone administration. We now test the hypothesis that fetal responsiveness to betamethasone depends on the gestational age at which glucocorticoid therapy is started.

DESIGN OF THE STUDY

1-h recordings of FHR (n=350) and fetal movements (n=310) made during a 5-day period (days 0-4) were available for analysis. The recordings had been obtained from 63 pregnant women at high risk for preterm delivery who received betamethasone (two doses of 12 mg 24 h apart) between 26 and 34 weeks' gestational age (wGA). The response to betamethasone, i.e. the direction and magnitude of change in FHR and movement parameters compared with baseline (day 0), was studied in relation to gestational age at drug administration.

RESULTS

Fetuses exposed to betamethasone at 29-34 wGA showed a decrease in FHR on day 1 (indicative of baroreceptor reflex), and reduced breathing activity and prolonged episodes of quiescence with a concomitant decrease in body movements on days 1 and 2. However, these changes were not observed if betamethasone administration occurred at 26-28 wGA. Betamethasone-induced reductions in FHR variability were similar in young and older fetuses.

CONCLUSIONS

Age-related differential responsiveness to betamethasone was found for all studied fetal processes (body and breathing movements, FHR, and quiescence), except FHR variability. Our results suggest ontogenic changes in the mechanisms presumed to underlie these processes (glucocorticoid receptor (GR) maturation, cardiovascular and neuro-endocrine development).

Immediate and delayed effects of antenatal corticosteroids on fetal heart rate: a randomized trial that compares betamethasone acetate and phosphate, betamethasone phosphate, and dexamethasone

OBJECTIVE

The purpose of this study was to evaluate the role of different formulations and different administration kinetics of antenatal corticosteroid therapy on fetal heart rate.

STUDY DESIGN

One hundred five patients who were at high risk for preterm delivery were assigned randomly to receive two injections of betamethasone acetate + phosphate, four injections of betamethasone phosphate, or four injections of dexamethasone phosphate. Computerized fetal heart rate was recorded daily through day 4.

RESULTS

The three formulations did not differ in their effect on fetal heart rate, which varied significantly as a function of the time of injection. During treatment (day 0-day 1), fetal heart rate variability increased (+9%, P <.05), as did the number of fetal movements felt by the mother (+60% at day 0, P <.001). After treatment (day 2-day 3), variability fell significantly (-14%, P <.01), as did accelerations (-35% at day 2, P <.01). No modifications were still detectable on day 4.

CONCLUSION

Antenatal corticotherapy is responsible for two different phases of fetal heart rate modifications that do not vary according to the corticosteroid or the dosage regimen.

Changes in umbilical artery flow velocity waveforms following maternal administration of betamethasone

In a retrospective cohort study we have previously shown that administration of betamethasone to women with a pregnancy complicated by absent end-diastolic flow in the umbilical artery (UA) is associated with altered UA flow velocity waveforms. To examine this phenomenon further we undertook a prospective study of 30 similar singleton pregnancies. Umbilical artery FVWs were recorded before and after betamethasone administration using real-time pulsed wave colour flow Doppler. The results of this prospective cohort were similar to those of the retrospective study allowing pooling of the data. Of the 55 total pregnancies with umbilical artery AEDF studied betamethasone administration was associated with the return of end-diastolic flow in 39 (71 per cent; 95 per centCI: 59-83 per cent). The median (range) duration of this change was 3 (1-10) days. There is no evidence that this change has either a beneficial or detrimental effect on foetal health. Administration of betamethasone to women with a pregnancy complicated by umbilical artery AEDF is associated with the transient return of end-diastolic flow in most cases. While the mechanisms underlying this effect are yet to be fully elucidated it has implications for foetal surveillance in these high-risk pregnancies.

Corticosteroids and fetal vasculature: effects of hydrocortisone, dexamethasone and betamethasone on human umbilical artery

OBJECTIVE

To investigate the direct effects of corticosteroids on human umbilical artery resistance, in vitro.

DESIGN

Prospective laboratory study.

SETTING

University teaching hospital.

SAMPLES AND METHODS

Umbilical artery samples were obtained following normal, term deliveries (n = 50) and dissected rings were suspended for isometric recording under physiological conditions. The effects of hydrocortisone (10(-9) - 10(-4) M), dexamethasone (10(-9) - 10(-4) M) and betamethasone (10(-9) - 10(-4) M) on umbilical artery resistance were measured in vitro.

MAIN OUTCOME MEASURES

Changes in umbilical artery resistance, in vitro.

RESULTS

Hydrocortisone (n = 12) exerted a vasodilatory effect on human umbilical artery at all concentrations studied compared with vehicle control experiments (n = 12) (P < 0.0001). The mean net relaxant effect of hydrocortisone ranged from 11.77% (10(-9) M) to 57.01% (10(-4)). Both exogenous compounds, dexamethasone (n = 12) and betamethasone (n = 12), similarly exerted a significant relaxant effect on human umbilical artery tone (P < 0.05-0.01), compared with vehicle control experiments (n = 12). The mean net relaxant effect of dexamethasone ranged from 14.43% (10(-9) M) to 38.12% (10(-4)) and that of betamethasone ranged from 6.02% (10(-9) M) to 42.30% (10(-4)), in a cumulatively increasing fashion. There was a non-significant trend towards a greater vasodilatory effect of dexamethasone than betamethasone at lower bath concentrations studied.

CONCLUSION

Corticosteroids exert a direct and potent vasodilatory effect on human umbilical artery resistance in vitro, thus providing an explanation for the previously unexplained vascular effects associated with antenatal administration of corticosteroids.

Changes in fetoplacental vessel flow velocity waveforms following maternal administration of betamethasone

OBJECTIVE

To determine the timing of the onset of the umbilical artery flow velocity waveform changes following maternal administration of betamethasone in pregnancies complicated by umbilical artery absent end-diastolic flow, and to explore whether these changes are associated with flow velocity waveform changes in other fetoplacental vessels.

SUBJECTS AND METHODS

This was a prospective study of 12 women with pregnancies complicated by umbilical artery absent end-diastolic flow. Flow velocity waveforms were recorded from the umbilical artery, fetal middle cerebral artery, renal artery, aorta and ductus venosus, before and after maternal betamethasone administration, using real-time pulsed wave Doppler.

RESULTS

In all 12 pregnancies, the administration of maternal betamethasone was followed by the return of end-diastolic flow within 24 h. End-diastolic flow was first observed at 4 h and was present in all women studied at 8 h. In addition, there was a statistically significant decrease in the pulsatility index in the fetal aorta at 8 h and the middle cerebral artery at 24 h. No change was observed in the ductus venosus or the renal artery flow velocity waveforms.

CONCLUSION

The findings suggest that, in pregnancies complicated by absent end-diastolic flow in the umbilical artery, maternally administered betamethasone induces a return in umbilical artery end-diastolic flow as early as 4 h, along with widespread vasodilatation throughout the fetoplacental vasculature.

Effects of maternal betamethasone administration on fetal and maternal blood pressure and heart rate in the baboon at 0.7 of gestation

OBJECTIVE

We sought to determine the effects of the intramuscular maternal administration of betamethasone to the pregnant baboon at 0.7 of gestation on fetal blood pressure and heart rate.

STUDY DESIGN

We treated pregnant baboons at 0.7 of gestation with intramuscular betamethasone (n = 4), at a weight-adjusted dose equivalent to the daily dose administered to women in preterm labor or with saline solution (n = 5). Four injections were given at 12-hour intervals. Fetal and maternal blood pressure and heart rate were recorded continuously. Within-group differences and between-group differences were analyzed with repeated measures analysis of variance.

RESULTS

Fetal blood pressure increased significantly after betamethasone treatment. Fetal heart rate, maternal blood pressure, and heart rate did not change.

CONCLUSION

Exposure of the developing primate fetus to exogenous glucocorticoid at 0.7 of gestation elevates fetal blood pressure. These findings confirm and extend the observations in the fetal sheep. Further studies are needed to evaluate the mechanisms that are involved and possible long-term consequences of these cardiovascular effects of antenatal glucocorticoid exposure in the fetal primate.

The effects of repeat doses of antenatal corticosteroids on maternal adrenal function

OBJECTIVE

The purpose of this study was to determine whether repeated doses of maternal corticosteroids suppress the maternal hypothalamic-pituitary-adrenal axis.

STUDY DESIGN

The low-dose corticotropin stimulation test (1.0 microg intravenously) was administered a median of 3 days after the last betamethasone dose to 18 pregnant women who had received at least 2 weekly courses of antenatal betamethasone and to 6 control subjects matched for gestational age who had not received antenatal corticosteroids.

RESULTS

The mean basal cortisol level was significantly depressed among women who had received betamethasone with respect to control subjects (1.9 +/- 1.5 vs 26.5 +/- 6.2 microg/dL; P <.001). The maternal cortisol level after corticotropin stimulation was significantly lower in all women who had received betamethasone (P <. 001). The mean time to attainment of peak cortisol level was significantly longer among women who had received betamethasone than among control subjects (37 +/- 6.8 vs 27.4 +/- 1.6 minutes; P <.001).

CONCLUSIONS

Repeated courses of betamethasone lead to barely detectable maternal basal cortisol levels and secondary adrenal insufficiency.

Effects of maternal dexamethasone administration on fetal Doppler flow velocity waveforms

OBJECTIVE

To investigate the effects of maternal dexamethasone administration on umbilical and fetal cerebral artery flow velocity waveforms.

DESIGN

Cross-sectional study.

SETTING

Department of Obstetrics and Gynaecology, Robert Ballanger Hospital, Aulnay-sous-Bois, France.

SAMPLE

Twenty-six pregnant women with singleton pregnancies considered at risk for preterm delivery. At baseline, all pregnancies had normal fetoplacental vascular resistance.

METHODS

These women were given weekly six intravenous doses of 4 mg of dexamethasone eight hours apart.

MAIN OUTCOME MEASURES

Doppler studies were performed from both umbilical artery (UA) and fetal middle cerebral artery (MCA) before (day 0), during (day 2), immediately after (day 4) and shortly after (day 7) every steroid course.

RESULTS

No significant variation was noted in both umbilical artery pulsatility index (PI) and fetal heart rate through dexamethasone therapy. Compared with mean initial values, we found on day 4 a significant decrease in MCA PI of 0.28 (F = 7.17, P < 0.001) and a significant increase in UA:MCA PI ratio of 0.08 (F = 3.85, P = 0.013); in contrast no significant change was documented on days 2 and 7 in both MCA pulsatility index and UA:MCA PI ratio. After multiple regression analysis, only the decrease in fetal middle cerebral artery pulsatility index on day 4 remained significant (F= 5.84, P= 0.001).

CONCLUSIONS

The current study finds in healthy fetuses a transient, significant and unexplained decrease in fetal middle cerebral artery impedance on the fourth day following maternal dexamethasone administration. Further basic research and clinical studies including larger sample sizes or pregnancies with fetoplacental dysfunction are needed.

Antenatal glucocorticoid treatment and cystic periventricular leukomalacia in very premature infants

BACKGROUND

Antenatal glucocorticoid therapy decreases the incidence of several complications among very premature infants. However, its effect on the occurrence of cystic periventricular leukomalacia, a major cause of cerebral palsy, remains unknown.

METHODS

We retrospectively analyzed a cohort of 883 live-born infants, with gestational ages ranging from 24 to 31 weeks, who were born between January 1993 and December 1996 at three perinatal centers in the Paris area. The mothers of 361 infants had received betamethasone before delivery, the mothers of 165 infants had received dexamethasone before delivery, and the mothers of 357 infants did not receive glucocorticoids. We compared the rates of cystic periventricular leukomalacia among the three groups of infants in bivariate and multivariate analyses after adjustment for confounding factors.

RESULTS

The rate of cystic periventricular leukomalacia was 4.4 percent among the infants whose mothers had received betamethasone, 11.0 percent among the infants whose mothers had received dexamethasone, and 8.4 percent among the infants whose mothers had not received a glucocorticoid. After adjustment for gestational age, the mode of delivery, and the presence or absence of chorioamnionitis, prolonged interval between the rupture of membranes and delivery (>24 hours), preeclampsia, and the use of tocolytic drugs, antenatal exposure to betamethasone was associated with a lower risk of cystic periventricular leukomalacia than was either the absence of glucocorticoid therapy (adjusted odds ratio, 0.5; 95 percent confidence interval, 0.2 to 0.9) or exposure to dexamethasone (adjusted odds ratio, 0.3; 95 percent confidence interval, 0.1 to 0.7). The adjusted odds ratio for the group of infants whose mothers had received dexamethasone as compared with the group of infants whose mothers had not received a glucocorticoid was 1.5 (95 percent confidence interval, 0.8 to 2.9).

CONCLUSIONS

Antenatal exposure to betamethasone but not dexamethasone is associated with a decreased risk of cystic periventricular leukomalacia among very premature infants.

Temporal changes in fetal cardiovascular, behavioural, metabolic and endocrine responses to maternally administered dexamethasone in the late gestation fetal sheep

OBJECTIVE

To determine the primary (0-12 h) and secondary (12-24 h) effects of dexamethasone on fetal heart rate, short term heart rate variation, blood pressure, breathing movements and electrocortical activity, blood gas exchange, metabolism and adrenocortical function in the late gestation sheep fetus.

DESIGN

Comparison of the effects of a single maternally administered intramuscular injection of dexamethasone (12 mg) with those of saline vehicle from 1 h before injection to 24 h post-injection. Fetal cardiovascular and behavioural parameters were recorded continuously. Fetal and maternal blood samples were taken at regular intervals for blood gas, glucose and lactate, cortisol and adrenocorticotrophin measurements.

SAMPLE

Sixteen chronically instrumented singleton fetal sheep at 127-133 days of gestation (term is about 147 days).

RESULTS

During the primary phase short term heart rate variation fell (P < 0.001), and this was associated with a transient fall in the incidence of fetal breathing movements, a fall in fetal heart rate and a rise in fetal blood pressure. By 12 h there was a significant increase in short term heart rate variation (P < 0.001) and a rise in fetal heart rate, but blood pressure and fetal breathing movements had returned to normal. Dexamethasone significantly reduced fetal PaO2 throughout most of the experimental period, particularly 1 h post-injection (P < 0.005). Fetal and maternal plasma cortisol and adrenocorticotrophin concentrations fell significantly from 1 h post-injection.

CONCLUSIONS

The effects of dexamethasone on fetal heart rate variation are more complex than previously described with both a fall and an increase observed depending on the time at which heart rate variation was measured after injection. Dexamethasone also caused a significant fall in fetal PaO2, and although this was not to hypoxic levels in normoxic fetuses it does raise questions about the potential impact of dexamethasone on chronically hypoxic fetuses.

Recent advances in the therapeutic management of preterm labour

Preterm labour and delivery pose an increasing problem to the obstetrician. Improvements in tocolysis with the recent introduction of new therapeutic targeting strategies, and a reappraisal of the safety and relative efficacy of some older compounds, have led to a tendency away from prescribing beta-sympathomimetic agents. Infection prophylaxis and promotion of fetal lung maturity are deemed advantageous, but treatment protocols have not been clarified. This review examines the important publications of the past year in these areas.