Effectiveness of antenatal steroids in obstetric subgroups

Antenatal corticosteroids in specific groups at risk of preterm birth: a systematic review

OBJECTIVE

This study aimed to synthesise available evidence on the efficacy of antenatal corticosteroid (ACS) therapy among women at risk of imminent preterm birth with pregestational/gestational diabetes, chorioamnionitis or fetal growth restriction (FGR), or planned caesarean section (CS) in the late preterm period.

METHODS

A systematic search of MEDLINE, EMBASE, CINAHL, Cochrane Library, Web of Science and Global Index Medicus was conducted for all comparative randomised or non-randomised interventional studies in the four subpopulations on 6 June 2021. Risk of Bias Assessment tool for Non-randomised Studies and the Cochrane Risk of Bias tool were used to assess the risk of bias. Grading of Recommendations Assessment, Development and Evaluations tool assessed the certainty of evidence.

RESULTS

Thirty-two studies involving 5018 pregnant women and 10 819 neonates were included. Data on women with diabetes were limited, and evidence on women undergoing planned CS was inconclusive. ACS use was associated with possibly reduced odds of neonatal death (pooled OR: 0.51; 95% CI: 0.31 to 0.85, low certainty), intraventricular haemorrhage (pooled OR: 0.41; 95% CI: 0.23 to 0.72, low certainty) and respiratory distress syndrome (pooled OR: 0.59; 95% CI: 0.45 to 0.77, low certainty) in women with chorioamnionitis. Among women with FGR, the rates of surfactant use (pooled OR: 0.38; 95% CI: 0.23 to 0.62, moderate certainty), mechanical ventilation (pooled OR: 0.42; 95% CI: 0.26 to 0.66, moderate certainty) and oxygen therapy (pooled OR: 0.48; 95% CI: 0.30 to 0.77, moderate certainty) were probably reduced; however, the rate of hypoglycaemia probably increased (pooled OR: 2.06; 95% CI: 1.27 to 3.32, moderate certainty).

CONCLUSIONS

There is a paucity of evidence on ACS for women who have diabetes. ACS therapy may have benefits in women with chorioamnionitis and is probably beneficial in FGR. There is limited direct trial evidence on ACS efficacy in women undergoing planned CS in the late preterm period, though the totality of evidence suggests it is probably beneficial.

PROSPERO REGISTRATION NUMBER

CRD42021267816.

Sex differences in modulation of fetoplacental vascular resistance in growth-restricted mouse fetuses following betamethasone administration: comparisons with human fetuses

BACKGROUND

Maternally administered corticosteroids are routinely used to accelerate fetal lung maturation in pregnancies at risk of early preterm delivery. Although, among the subgroup with growth restriction, a majority show a temporary improvement in umbilical artery Doppler waveforms that may be sustained up to 7 days, a minority will acutely decompensate in response to corticosteroids in association with deteriorating umbilical and fetal Doppler waveforms. The basis for such acute Doppler changes is presently unknown. Our group has developed a noninvasive ultrasound methodology to measure wave reflections in the umbilical artery and have established that wave reflection metrics are sensitive to structural changes in the placental vasculature and to acute changes in vascular tone. Using this approach, we demonstrated in healthy pregnant mice that fetoplacental vascular resistance decreased in betamethasone-treated mice compared with saline-treated controls.

OBJECTIVE

This study aimed to investigate the effects of betamethasone administration on the wave reflection metrics in a mouse model of fetal growth restriction and to compare these findings with equivalent measurements in human fetuses.

STUDY DESIGN

Pregnant CD-1 mice were housed from embryonic day 14.5 to embryonic day 17.5 in either a normoxic (21% O₂, n=24) or hypoxic environment (11% O₂, n=22), the latter being an established mouse model of fetal growth restriction. To investigate the effect of maternally administered betamethasone on the fetoplacental vasculature, ultrasound imaging was performed at baseline and 4 hours after treatment (either betamethasone or sterile saline). Umbilical artery wave reflection metrics were compared between the groups and for the effect of fetal sex. In addition, a cohort of 10 pregnant women with elevated umbilical artery pulsatility index and evidence of fetal growth restriction and 6 controls were imaged before and after corticosteroid administration.

RESULTS

In the mouse model, after betamethasone administration, the female fetuses from the hypoxia group showed a 15% increase in umbilical artery diameter, a 98% increase in umbilical artery blood flow, and a 27% decrease in umbilical artery reflection coefficient, whereas the males from the hypoxia group showed no substantial changes. In agreement with our mouse findings, umbilical artery reflections were found to be larger in human growth-restricted fetuses than controls in women at risk of preterm birth.

CONCLUSION

Our studies provide insight into the mechanism whereby the human growth-restricted fetus may exhibit a temporary favorable fetoplacental vascular response to maternally administered corticosteroids. Further investigations are needed to understand why the male growth-restricted fetus seems unable to mount this favorable vascular response.

Antenatal corticosteroids in preterm small-for-gestational age infants: a systematic review and meta-analysis

OBJECTIVE

This study aimed to estimate the effect of antenatal corticosteroid administration on neonatal mortality and morbidity in preterm small-for-gestational age infants through a systematic review and meta-analysis.

DATA SOURCES

A predefined, systematic search was conducted through Ovid MEDLINE, Embase, Scopus, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, World Health Organization International Clinical Trial Registry Platform, and ClinicalTrials.gov yielding 5324 articles from 1970 to 2019.

STUDY ELIGIBILITY CRITERIA

Eligible studies compared neonatal morbidity and mortality among small-for-gestational age infants delivered preterm who received antenatal corticosteroids with those who did not.

METHODS

The primary outcome was neonatal mortality. Secondary outcomes were respiratory distress syndrome, necrotizing enterocolitis, intraventricular hemorrhage and periventricular leukomalacia, bronchopulmonary dysplasia or chronic lung disease of prematurity, or neonatal sepsis. We assessed heterogeneity by means of Higgins I² statistic and Cochran's Q test and calculated pooled odds ratios with 95% confidence intervals using random effects models.

RESULTS

A total of 16 observational cohort and case-control studies published from 1995 to 2018 met the selection criteria for the systematic review and included 8989 preterm small-for-gestational age infants. Antenatal corticosteroid administration was explicitly reported among 8376 small-for-gestational age infants; 4631 (55.3%) received antenatal corticosteroids and 3741 (44.7%) did not. Of note, 13 studies including 6387 preterm small-for-gestational age infants were then included in the meta-analysis. Neonatal mortality was significantly lower among infants who received antenatal corticosteroids than those who did not (12 studies: 12.8% vs 15.1%; pooled odds ratio, 0.63; 95% confidence interval, 0.46-0.86), with significant heterogeneity between studies (I²=55.1%; P=.011). There was no significant difference in respiratory distress syndrome (12 studies: odds ratio, 0.89; 95% confidence interval, 0.69-1.15), necrotizing enterocolitis (7 studies: odds ratio, 0.93; 95% confidence interval, 0.70-1.22), intraventricular hemorrhage and periventricular leukomalacia (10 studies: odds ratio, 0.82; 95% confidence interval, 0.56-1.20), bronchopulmonary dysplasia or chronic lung disease of prematurity (8 studies: odds ratio, 1.11; 95% confidence interval, 0.88-1.41), or neonatal sepsis (6 studies: odds ratio, 1.13; 95% confidence interval, 0.86-1.49).

CONCLUSION

These data indicate that antenatal corticosteroid administration reduces neonatal mortality in small-for-gestational age infants delivered preterm, with no apparent effect on neonatal morbidity. This supports the use of antenatal corticosteroids to reduce neonatal mortality in pregnancies with small-for-gestational age infants at risk of preterm birth.

Lack of relationship between cord blood erythropoietin and intraventricular hemorrhage in premature neonates: a controversial result

PURPOSE

The aim of this study was to assess the incidence and risk factors of intraventricular hemorrhage (IVH) as well as the role of cord blood erythropoietin (EPO) level in predicting the possibility of IVH in premature neonates.

MATERIALS AND METHODS

This prospective study included 140 preterm neonates born at hospitals affiliated to Shiraz University of Medical Sciences from May 2014 to April 2015. Complete blood count and cord blood EPO level was measured after birth. Brain ultrasonography was performed at 3 and 7-10 days after birth in these newborns.

RESULTS

Brain ultrasonography showed IVH in 8.57% (12/140) until the third day and 20% (28/140) at 7-10 days of life in premature neonates. Early gestational age, low birth weight, low Apgar score, and failure to give prenatal steroid were significant risk factors for developing IVH. The mean level of cord blood EPO was 20.95 ± 21.09 mIU/mL in premature newborns without IVH and 15.82 ± 17.11 mIU/mL with IVH. There was no correlation between the cord blood EPO and IVH in premature newborns.

CONCLUSION

Antenatal steroids therapy should be encouraged among women at risk of premature delivery. Our results showed that the cord blood EPO was not correlated with IVH in preterm neonates and further research is required to assess this relationship.

Intrauterine Growth Restriction and Patent Ductus Arteriosus in Very and Extremely Preterm Infants: A Systematic Review and Meta-Analysis

It is generally accepted that intrauterine growth restriction (IUGR) increases morbidity and mortality among very preterm neonates. However, evidence is hampered by the widespread practice of using the terms small for gestational age (SGA) and IUGR as synonyms. We conducted a systematic review of studies reporting on the association between IUGR/SGA and patent ductus arteriosus (PDA). PubMed/MEDLINE and EMBASE databases were searched. Of 993 studies reviewed, 47 (50,790 infants) were included. Studies were combined using a random effects model and sources of heterogeneity were determined by subgroup and meta-regression analyses. Meta-analysis of all included studies showed a significantly reduced risk of PDA in the SGA/IUGR group with an odds ratio (OR) of 0.82, and a 95% confidence interval (CI) of 0.70 to 0.96 (p = 0.015). Of the 47 studies, only 7 used a definition for growth restriction that went beyond birth weight (BW) for gestational age (GA). When pooled, meta-analysis could not demonstrate a significant effect size (OR 1.31, 95% CI 0.75 to 2.27, p = 0.343). Moreover, the significantly reduced risk of PDA was found in the 25 studies defining SGA as BW <10th percentile (OR 0.81, 95% CI 0.66 to 0.98, p = 0.032), but not in the 6 studies defining SGA as BW <3rd (OR 1.09, 95% CI 0.70 to 1.71, p = 0.694), or in the 27 studies using a more refined definition of PDA (i.e., hemodynamically significant PDA or PDA requiring treatment, OR 0.87, 95% CI 0.72 to 1.04, p = 0.133). In addition, we found that GA was significantly higher in the SGA/IUGR group (18 studies, mean difference 0.63 weeks, 95% CI 0.24 to 1.03, p = 0.002). Meta-regression analysis confirmed the correlation between this difference in GA and PDA risk. In summary, we observed marked heterogeneity across studies in the definition of growth restriction and PDA, and we found differences between the control and growth-restricted groups in relevant baseline characteristics, such as GA. Therefore, our meta-analysis could not provide conclusive evidence on the association between growth restriction and PDA.

Structural and transcriptomic response to antenatal corticosteroids in an Erk3-null mouse model of respiratory distress

BACKGROUND

Neonatal respiratory distress syndrome in preterm infants is a leading cause of neonatal death. Pulmonary insufficiency-related infant mortality rates have improved with antenatal glucocorticoid treatment and neonatal surfactant replacement. However, the mechanism of glucocorticoid-promoted fetal lung maturation is not understood fully, despite decades of clinical use. We previously have shown that genetic deletion of Erk3 in mice results in growth restriction, cyanosis, and early neonatal lethality because of pulmonary immaturity and respiratory distress. Recently, we demonstrated that the addition of postnatal surfactant administration to antenatal dexamethasone treatment resulted in enhanced survival of neonatal Erk3-null mice.

OBJECTIVE

To better understand the molecular underpinnings of corticosteroid-mediated lung maturation, we used high-throughput transcriptomic and high-resolution morphologic analysis of the murine fetal lung. We sought to examine the alterations in fetal lung structure and function that are associated with neonatal respiratory distress and antenatal glucocorticoid treatment.

STUDY DESIGN

Dexamethasone (0.4 mg/kg) or saline solution was administered to pregnant dams on embryonic days 16.5 and 17.5. Fetal lungs were collected and analyzed by microCT and RNA-seq for differential gene expression and pathway interactions with genotype and treatment. Results from transcriptomic analysis guided further investigation of candidate genes with the use of immunostaining in murine and human fetal lung tissue.

RESULTS

Erk3(-/-) mice exhibited atelectasis with decreased overall porosity and saccular space relative to wild type, which was ameliorated by glucocorticoid treatment. Of 596 differentially expressed genes (q < 0.05) that were detected by RNA-seq, pathway analysis revealed 36 genes (q < 0.05) interacting with dexamethasone, several with roles in lung development, which included corticotropin-releasing hormone and surfactant protein B. Corticotropin-releasing hormone protein was detected in wild-type and Erk3(-/-) lungs at E14.5, with significantly temporally altered expression through embryonic day 18.5. Antenatal dexamethasone attenuated corticotropin-releasing hormone at embryonic day 18.5 in both wild-type and Erk3(-/-) lungs (0.56-fold and 0.67-fold; P < .001). Wild type mice responded to glucocorticoid administration with increased pulmonary surfactant protein B (P = .003). In contrast, dexamethasone treatment in Erk3(-/-) mice resulted in decreased surfactant protein B (P = .012). In human validation studies, we confirmed that corticotropin-releasing hormone protein is present in the fetal lung at 18 weeks of gestation and increases in expression with progression towards viability (22 weeks of gestation; P < .01).

CONCLUSION

Characterization of whole transcriptome gene expression revealed glucocorticoid-mediated regulation of corticotropin-releasing hormone and surfactant protein B via Erk3-independent and -dependent mechanisms, respectively. We demonstrated for the first time the expression and temporal regulation of corticotropin-releasing hormone protein in midtrimester human fetal lung. This unique model allows the effects of corticosteroids on fetal pulmonary morphologic condition to be distinguished from functional gene pathway regulation. These findings implicate Erk3 as a potentially important molecular mediator of antenatal glucocorticoid action in promoting surfactant protein production in the preterm neonatal lung and expanding our understanding of key mechanisms of clinical therapy to improve neonatal survival.

Association of Antenatal Corticosteroids With Mortality, Morbidity, and Neurodevelopmental Outcomes in Extremely Preterm Multiple Gestation Infants

IMPORTANCE

Little is known about the effects of antenatal corticosteroids (ANS) on extremely preterm multiples.

OBJECTIVE

To examine if use of ANS is associated with improvement in major outcomes in extremely preterm multiples.

DESIGN, SETTING, AND PARTICIPANTS

Infants with a gestational age between 22 and 28 weeks born at a National Institute of Child Health and Human Development Neonatal Research Network center were studied between January 1998 and December 2013. Generalized estimating equation models were used to generate adjusted relative risks (aRR) controlling for important maternal and neonatal variables.

EXPOSURE

Antenatal corticosteroids.

MAIN OUTCOMES AND MEASURES

In-hospital mortality and the composite outcome of neurodevelopmental impairment at 18 to 22 months' corrected age or death before assessment.

RESULTS

A total of 6925 multiple-birth infants were studied; 5775 of 6925 (83.4%) were twins, and 4276 (61.7%) were white. Of the total study population, 6094 (88%) were born to women who received ANS. In-hospital mortality was lower among infants with exposure to ANS vs no exposure (aRR = 0.87; 95% CI, 0.78-0.96). Neurodevelopmental impairment or death was not significantly lower among those exposed to ANS vs no exposure (aRR = 0.93; 95% CI, 0.84-1.03). Other adverse outcomes that occurred less frequently among infants of women receiving ANS included severe intraventricular hemorrhage (aRR = 0.68; 95% CI, 0.58-0.78) and the combined outcomes of necrotizing enterocolitis or death and severe intraventricular hemorrhage or death. Subgroup analyses indicated that exposure to ANS was associated with a lower risk of mortality and a lower composite of neurodevelopmental impairment or mortality among nonsmall for gestational age multiples (aRR = 0.82; 95% CI, 0.74-0.92; and aRR = 0.89; 95% CI, 0.80-0.98, respectively) and a higher risk among small for gestational age multiples (aRR = 1.40; 95% CI, 1.02-1.93; and aRR = 1.62; 95% CI, 1.22-2.16, respectively). Antenatal corticosteroids were associated with higher neurodevelopmental impairment or mortality among multiple-birth infants of mothers with diabetes (aRR = 1.55; 95% CI, 1.00-2.38) but not among infants of mothers without diabetes (aRR = 0.91; 95% CI, 0.83-1.01).

CONCLUSIONS AND RELEVANCE

Compared with no exposure, exposure to ANS was associated with a lower risk of mortality in extremely preterm multiples, with no significant differences in the composite of neurodevelopmental impairment or death. Future research should investigate the increased risks of mortality and the composite of neurodevelopmental impairment or death associated with exposure to corticosteroids among small for gestational age multiples.

Antenatal Corticosteroids for Reducing Adverse Maternal and Child Outcomes in Special Populations of Women at Risk of Imminent Preterm Birth: A Systematic Review and Meta-Analysis

BACKGROUND

This study synthesizes available evidence on antenatal corticosteroids (ACS) use among special subgroups of women at risk of imminent preterm birth, including those (1) with pregestational and gestational diabetes mellitus, (2) undergoing elective caesarean section (CS) in late preterm (34 to<37 weeks), (3) with chorioamnionitis, and (4) with growth-restricted fetuses.

METHODS

A systematic search of MEDLINE, EMBASE, CINAHL, Cochrane Library, POPLINE, and World Health Organization Regional Databases was conducted for all comparative studies. Two reviewers independently determined study eligibility, extracted data, and assessed study quality. Pooled mean differences and odds ratios with 95% confidence intervals were estimated from available data, based on fixed- and random-effects models, as appropriate.

RESULTS

No eligible studies were identified for ACS use in diabetic pregnant women or those undergoing elective CS at late preterm. Nine studies each on ACS use in women with chorioamnionitis and in women with fetal growth restriction met inclusion criteria; eight studies were separately included in the meta-analyses for the two subpopulations. For ACS administration in women with chorioamnionitis, pooled analyses showed reductions in neonatal mortality (OR: 0.49, 95% CI: 0.34-0.73), respiratory distress syndrome (OR: 0.58, 95% CI: 0.44-0.76), intraventricular haemorrhage (OR: 0.41, 95% CI: 0.24-0.69), and severe intraventricular haemorrhage (OR: 0.40, 95% CI: 0.24-0.69). Maternal and long-term newborn outcomes were not reported. Effects of ACS use were inconclusive for cases with fetal growth restriction.

CONCLUSION

Direct evidence on the effectiveness and safety of ACS is lacking for diabetic pregnant women at risk of preterm birth and those undergoing elective late-preterm CS, though this does not necessarily recommend against their use in diabetic women. While evidence remains inconclusive for women with growth-restricted preterm neonates, ACS appears to benefit preterm neonates delivered by women with chorioamnionitis. High-quality studies on maternal and long-term child outcomes in more diverse settings are needed to establish the balance of potential harms versus benefits in using ACS for these understudied subgroups.

Structural and molecular regulation of lung maturation by intratracheal vascular endothelial growth factor administration in the normally grown and placentally restricted fetus

Inhibition of hypoxia signalling leads to respiratory distress syndrome (RDS), whereas administration of vascular endothelial growth factor (VEGF), the most widely characterized hypoxia responsive factor, protects from RDS. In the lung of the chronically hypoxaemic placentally restricted (PR) fetus, there is altered regulation of hypoxia signalling. This leads to reduced surfactant maturation in late gestation and provides evidence for the increased risk of RDS in growth restricted neonates at birth. We evaluated the effect of recombinant human VEGF administration with respect to bypassing the endogenous regulation of hypoxia signalling in the lung of the normally grown and PR sheep fetus. There was no effect of VEGF administration on fetal blood pressure or fetal breathing movements. We examined the effect on the expression of genes regulating VEGF signalling (FLT1 and KDR), angiogenesis (ANGPT1, AQP1, ADM), alveolarization (MMP2, MMP9, TIMP1, COL1A1, ELN), proliferation (IGF1, IGF2, IGF1R, MKI67, PCNA), inflammation (CCL2, CCL4, IL1B, TNFA, TGFB1, IL10) and surfactant maturation (SFTP-A, SFTP-B, SFTP-C, SFTP-D, PCYT1A, LPCAT, LAMP3, ABCA3). Despite the effects of PR on the expression of genes regulating airway remodelling, inflammatory signalling and surfactant maturation, there were very few effects of VEGF administration on gene expression in the lung of both the normally grown and PR fetus. There were, however, positive effects of VEGF administration on percentage tissue, air space and numerical density of SFTP-B positive alveolar epithelial cells in fetal lung tissue. These results provide evidence for the stimulatory effects of VEGF administration on structural maturation in the lung of both the normally grown and PR fetus.

The Effects of Antenatal Corticosteroids on Short- and Long-Term Outcomes in Small-for-Gestational-Age Infants

AIM

To evaluate the effect of antenatal corticosteroids (ANS) on short- and long-term outcomes in small-for-gestational age (SGA) infants.

METHODS

A retrospective database analysis was performed. A total of 1,931 single infants (birth weight <1,500 g) born at a gestational age between 22 weeks and 33 weeks 6 days who were determined to be SGA registered in the Neonatal Research Network Database in Japan between 2003 and 2007 were evaluated for short-term outcome and long-term outcome.

RESULTS

ANS was administered to a total of 719 infants (37%) in the short-term outcome evaluation group and 344 infants (36%) in the long-term outcome evaluation group. There were no significant differences between the ANS group and the no-ANS group for primary short-term outcome (adjusted odds ratio (OR) 0.73; 95% confidence interval (CI) 0.45-1.20; P-value 0.22) or primary long-term outcome (adjusted OR 0.69; 95% CI 0.40-1.17; P-value 0.17).

CONCLUSIONS

Our results show that ANS does not affect short- or long-term outcome in SGA infants when the birth weight is less than 1500 g. This study strongly suggests that administration of ANS resulted in few benefits for preterm FGR fetuses.

Miracle baby: managing extremely preterm birth in rural Uganda

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

Corticosteroids effect on caspase 3 expression in an in-vitro model of hypoxic brain cells

OBJECTIVE

Effects of corticosteroids (CS) in the brain of growth-restricted fetus remain largely unstudied. We investigated if dexamethasone (DXM) exposure contributes to neuronal injury in an in-vitro model of neuronal cells under hypoxic conditions (surrogate for fetal growth restriction).

STUDY DESIGN

U87 glioblastoma cells exposed to hypoxic or normoxic conditions for 10 h were incubated in the absence or presence of DXM for 48 h. Apoptosis as possible indicator of neurotoxicity was determined using a caspase-3-specific activity assay and western blotting. Caspase-3 was calculated as percentage of mean caspase-3 cleavage. Each experiment was performed in triplicate (n = 48). Caspase 3 activity in cell culture media was also measured by ELISA.

RESULTS

Pro-caspase-3 (32 kDa) was expressed in culture, but activated 17 Kd caspase 3 was not expressed in cell lysate. There was no difference in ratio of caspase 3 activation when U87 cells were exposed to 10 v of hypoxia as compared to normoxia (0.46 ± 0.44 versus 0.37 ± 0.37). The pro-apoptotic effects of DXM were not increased by pre-exposure to hypoxia: (0.37 ± 0.37 versus 0.47 ± 0.40).

CONCLUSION

The addition of DXM to hypoxic U87 cells had no additive or synergistic effects on the activation of caspase 3. Therefore, we speculate that the administration of CS in the setting of fetal growth restriction would not lead to increased apoptosis with potential neuronal injury.

Are antenatal steroids beneficial to severely growth restricted fetuses?

Antenatal steroids (AS) have been shown to enhance fetal maturation in preterms and to improve outcome. The aim of this study was to evaluate the efficacy of AS in premature severely intrauterine growth restricted infants. The electronic data of 149 inborn, single infants born 24 to 31 6/7 weeks of GA and with a BW ≤ 3rd percentile were reviewed. Infants with congenital anomalies and syndromes were excluded. We compared the outcome of those who received 2 doses of AS (group A, 87 infants) with those who did not receive AS (group B, 62 infants). Sixty-eight infants in group A and 53 in group B were discharged home alive. AS did not improve the neonatal outcome, with the exception of a better cord pH and 5-min Apgar and we did not observe a significant difference in the Griffith's test at 2 years of corrected age, although there was a trend to a higher incidence of severe global delay in the steroid group. In view of the potential cerebral and CVS risks associated with high circulating steroids, the indications for AS in such a population need to be re-evaluated.

Antenatal steroids and the IUGR fetus: are exposure and physiological effects on the lung and cardiovascular system the same as in normally grown fetuses?

Glucocorticoids are administered to pregnant women at risk of preterm labour to promote fetal lung surfactant maturation. Intrauterine growth restriction (IUGR) is associated with an increased risk of preterm labour. Hence, IUGR babies may be exposed to antenatal glucocorticoids. The ability of the placenta or blood brain barrier to remove glucocorticoids from the fetal compartment or the brain is compromised in the IUGR fetus, which may have implications for lung, brain, and heart development. There is conflicting evidence on the effect of exogenous glucocorticoids on surfactant protein expression in different animal models of IUGR. Furthermore, the IUGR fetus undergoes significant cardiovascular adaptations, including altered blood pressure regulation, which is in conflict with glucocorticoid-induced alterations in blood pressure and flow. Hence, antenatal glucocorticoid therapy in the IUGR fetus may compromise regulation of cardiovascular development. The role of cortisol in cardiomyocyte development is not clear with conflicting evidence in different species and models of IUGR. Further studies are required to study the effects of antenatal glucocorticoids on lung, brain, and heart development in the IUGR fetus. Of specific interest are the aetiology of IUGR and the resultant degree, duration, and severity of hypoxemia.

Dosage regimen of antenatal steroids prior to preterm delivery and effects on maternal and neonatal outcomes

OBJECTIVE

The objective of this study was to compare the effects of two betamethasone dosage regimens on selected parameters in mothers and on the status of the preterm newborn.

METHODS

The analysis included 121 patients who gave birth by gestational week 35 and within 7 days after the completion of a full course of steroid treatment (24 mg). The study group consisted of 45 patients receiving six 4-mg doses of betamethasone every 8 h. The control group consisted of 76 patients receiving two 12-mg doses of betamethasone separated by 24 h.

RESULTS

After treatment, a significant increase in the leukocyte count was observed in the control group. Significant reductions in the erythrocyte counts, hemoglobin levels and hematocrit after treatment were also found in the control group. The post-natal status of newborns did not differ significantly between groups. The betamethasone dosage regimen used did not affect the incidence of moderate and severe respiratory disorders, intraventricular hemorrhage (IVH), necrotizing enterocolitis (NEC), retinopathy (ROP), infection, hyperbilirubinemia or anemia in neonates. Mild respiratory disorders were slightly more common in the study group.

CONCLUSION

A reduction in the single steroid dose administered to patients at risk of premature birth may reduce maternal side-effects.

Singleton preterm births in korle bu teaching hospital, accra, ghana - origins and outcomes

SUMMARY OBJECTIVE

To determine the singleton preterm birth rate, the relative proportions of the clinical categories of preterm births and to compare the outcomes in these categories.

SETTING

Department of Obstetrics & Gynaecology, Korle Bu Teaching Hospital.

PARTICIPANTS

Preterm births from 1(st) July to 31(st) December 2003.

RESULTS

Out of a total of 4731 singleton births 440 were preterm, giving a preterm birth rate of 9.3%. One hundred and eighty-five (42%, [95% Confidence Interval (CI) 37.4%, 46.8%]) preterm births followed spontaneous onset of preterm labour (group A), 82 (18.6%, [95% CI 15.2%, 22.7%]) followed preterm premature rupture of membranes, PPROM (group B) and 173 (39.3%, [95% CI 34.8%, 44.1%]) were medically indicated (group C). The commonest indication for delivery in group C was severe pre-eclampsia/eclampsia. Although there was no significant difference in the mean gestational ages at delivery between the groups, babies in group C had significantly lower birth weights. No differences in sex ratios, still-birth rates, or incidence of low Apgar scores were found. Babies in group C were significantly more likely to be admitted to the neonatal intensive care unit (NICU) and had a significantly higher perinatal death rate. Survivors of NICU admission among group C babies spent significantly longer periods in hospital before discharge.

CONCLUSION

Outcomes of preterm births in Korle Bu Teaching Hospital are less favourable among indicated preterm births than among spontaneous or PPROM-related preterm births. A detailed study of the causes of neonatal morbidity and mortality is suggested to determine any differences between the three groups.

Respiratory outcome in preterm small for gestational age fetuses with or without abnormal umbilical artery Doppler and/or maternal hypertension

OBJECTIVE

To study respiratory outcome in preterm small for gestational age (SGA) fetuses with or without signs of intrauterine growth restriction due to placental insufficiency, and with or without maternal hypertension.

METHODS

This was a retrospective study of 187 neonates with birth weight <10(th) percentile and gestational age <34 weeks. Results from umbilical artery Doppler velocimetry were used to identify the abnormal Doppler subgroup.

RESULTS

No significant difference in respiratory outcome between SGA fetuses with normal (SGA-N) or abnormal (SGA-A) umbilical artery Doppler examination was found. Within the SGA-A group, the respiratory distress syndrome (RDS) incidence (OR 5.6, 95% CI 1.7-18.3), RDS grade (OR 6.7, 95% CI 1.2-38.5), and need for surfactant (OR 5.3, 95% CI 1.1-24.4) were higher in infants of women with hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome as compared to those of normotensive mothers.

CONCLUSIONS

Lung maturation is not accelerated with placental insufficiency. SGA-A fetuses of mothers with HELLP syndrome have a significantly poorer respiratory outcome than those with healthy mothers. Possibly, fetuses of mothers with HELLP syndrome are subjected to 'oxidative stress' causing lung damage rather than lung maturation.

A comparison of the effectiveness of single-dose vs multi-dose antenatal corticosteroids in pre-term neonates

The purpose of this study was to compare the outcome between exposure to single vs multiple courses of antenatal corticosteroids (AC) in pre-term births. The study involved 704 neonates delivered between 24-32 weeks. Maternal and perinatal outcome were compared between 294 (42%) neonates who received no AC; 257 (36%) who received single AC and 153 (22%) who received multiple AC. Any AC compared with no AC showed decreased composite neonatal morbidity (51% vs 62%, p = 0.004, odds ratio (OR) = 0.6), neonatal death (52% vs 62%, p = 0.004, OR = 0.6) and hyaline membrane disease (45% vs 57%, p = 0.002, OR = 0.6) with increased chorioamnionitis (17% vs 11%, p = 0.037, OR = 1.6) and pulmonary oedema (12% vs 1%, p = 0.0001, OR = 13). Multiple AC compared with single AC was associated with increased positive maternal cultures (44% vs 31%, p < or =0.005, OR = 1.8), small for gestational age infants (35% vs 21%, p = 0.001, OR = 2) and intraventricular haemorrhage (45% vs 34%, p <0.05, OR = 1.6). Multiple corticosteroid courses when compared with single corticosteroid course did not further reduce composite neonatal morbidity but increased the risk of positive maternal cultures and neonatal small for gestational age and intraventricular haemorrhage.

Timing of indicated delivery after antenatal steroids in preterm pregnancies with severe hypertension

OBJECTIVES

To evaluate the effect of the time interval between administering antenatal steroids needed to accelerate fetal lung maturity and indicated delivery in preterm pregnancies complicated by severe hypertension, as determined by maternal and perinatal outcomes.

METHODS

The Nova Scotia Atlee Perinatal Database was used to identify a population-based cohort of women with severe hypertension who delivered an infant between 1989 and 2002. Women were included if they received antenatal steroids and required delivery between 26 and 34 weeks gestation. Multivariate logistic regression analyses were conducted to evaluate the effect of time interval on maternal and perinatal mortality, maternal hemorrhagic and hypertension-associated morbidity, and perinatal respiratory, infectious, and prematurity-associated morbidity, while controlling for confounding variables.

RESULTS

172 pregnancies satisfied inclusion and exclusion criteria. Betamethasone was the most commonly used corticosteroid to accelerate fetal lung maturity (95%). Among infants delivered at 26 to 34 weeks, adjusted analyses showed a reduction in risk of depression at birth (RR, 0.54; 95% CI, 0.24 to 0.97) and need for surfactant (RR, 0.50; 95% CI, 0.25 to 0.95) when the time interval from steroid administration to delivery was >48 hours compared with <or= 48 hours. Adjusted analyses in a subgroup of women with cesarean delivery (81% of deliveries) demonstrated no differences in rates maternal or neonatal morbidity.

CONCLUSIONS

The rates of most adverse maternal and neonatal outcomes in preterm pregnancies with severe hypertension delivered at 26 to 34 weeks are not affected by timing from steroid administration to delivery. These data support the decision for delivery based mainly on obstetrical indications.

No short-term benefits of antenatal corticosteroid treatment in severely preterm growth restricted fetuses: a case-control study

BACKGROUND

Antenatal corticosteroid administration to premature, growth restricted fetuses may not be beneficial and even have adverse effects on neonatal outcome.

AIMS

To determine if preterm growth restricted fetuses benefit from antenatal corticosteroids.

STUDY DESIGN

Retrospective cohort study.

METHODS

All singleton pregnancies with growth restricted fetuses delivered at our department before 34 weeks' gestation or weighing less than 1500 g, between January 2001 and December 2005, were retrospectively reviewed. Neonatal outcome was compared between growth restricted fetuses (defined as abnormal flow patterns in umbilical and middle cerebral arteries) that received antenatal CST (CST group) and those who did not receive antenatal CST (no CST group). The administration of CST appeared to be quasi randomized.

RESULTS

A total of 88 pregnancies fulfilled the inclusion criteria (CST group, n=54; no CST group, n=34). The incidence of neonatal respiratory distress syndrome in the CST and no CST group was 42% (22/54) and 50% (17/34), respectively (p=0.44). Neonatal mortality in the CST and no CST group was 9% (5/54) and 12% (4/34), respectively (p=0.73). The prevalence of adverse neonatal outcome (neonatal mortality, major neonatal morbidity or severe cerebral lesions) in the CST and no CST group was 28% (15/54) versus 24% (8/34), (p=0.62).

CONCLUSIONS

Administration of CST to growth restricted preterm fetuses does not appear to be beneficial with respect to short term neonatal outcome.

Betamethasone impairs cerebral blood flow velocities in very premature infants with severe chronic lung disease

OBJECTIVE

To assess betamethasone (BM) effects on the cerebral hemodynamics of neonates with severe chronic lung disease (CLD).

STUDY DESIGN

Intravenous BM was given once daily for 6 consecutive days to 12 infants (birth weight: 698 g [range, 650-884 g], gestational age: 25.3 weeks [range, 25-26.4 weeks]) at a postnatal age of 34 days (range, 28-36 days). Cerebral blood flow velocities (CBFVs) were recorded prospectively in the anterior cerebral artery (ACA) and the lenticulostriate artery (LSA) before, during, and after treatment, using Doppler flowmetry.

RESULTS

The decrease in systolic and diastolic velocities was maximum on the 5th day, reaching 32% (95% confidence interval [CI], 23%-42%) and 58% (95% CI, 39%-64%) from baseline in the ACA, and 44% (95% CI, 29%-50%) and 57% (95% CI, 33%-66%) in the LSA, respectively. The resistance index (RI) increased significantly in both arteries during treatment. Return to baseline values was observed after BM was stopped. The change in velocities and RI was independent of arterial blood gas and blood pressure variations.

CONCLUSIONS

BM decreased the CBFVs of premature infants, suggesting a vasoconstrictor effect in both superficial and deep arterial vessels. Caution is recommended when BM is used to treat preterm infants with severe CLD.

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.

Antenatal steroids and risk of bronchopulmonary dysplasia: a lack of effect or a case of over-adjustment?

Although antenatal steroids reduce risk factors for bronchopulmonary dysplasia (BPD) in preterm infants, their effect on BPD is conflicting. We hypothesised that the lack of protective effect found in some studies could derive from over-adjustment during analysis, caused by controlling for factors intermediate in the causal pathway between treatment and outcome. We prospectively studied a cohort of infants 23-32 weeks gestation <1500 g, admitted to 10 tertiary-level neonatal units in Lombardy (Italy) in 1999-2002; 1118 neonates out of 1314 survived to 36 weeks; 15.9% developed BPD (oxygen requirement at 36 weeks); 82% were treated with steroids. In univariable analysis, steroids were not significantly protective against BPD; some intermediate factors (mechanical ventilation, greater severity of illness as measured by Clinical Risk Index for Babies score, patent ductus arteriosus) were significantly positively associated with (i.e. were risk factors for) BPD (OR = 11.0, 1.55, 4.42, respectively, all P < 0.001), and negatively associated with (i.e. prevented by) steroids (OR = 0.58, 0.92, and 0.58, respectively, all P < 0.01). In multiple logistic regression models using propensity scores, without the above-mentioned intermediate risk factors, steroid-treated infants had a lower risk of BPD (OR 0.59 [95% CI 0.36, 0.97], P = 0.036); male sex (OR = 2.08), late-onset sepsis (OR = 4.26), and birthweight (OR = 0.63 for 100 g increase) were also associated with BPD, all P < 0.001. When intermediate risk factors for BPD were also added to the model, the effect of steroids disappeared; ventilation (OR = 3.03), increased illness severity (OR = 1.11), and patent ductus arteriosus (OR = 1.90) were significant risk factors. This study suggests that including variables that are potential mediators in the causal chain can obscure the ability to detect a protective effect of treatment. We observed such a phenomenon in our analyses of the relationship between antenatal steroids and BPD, suggesting that steroid effect is partly mediated through a reduction in the classical risk factors.

The combined effect of betamethasone and ritodrine on the middle cerebral artery in low risk third trimester pregnancies

AIMS

To evaluate the effect of antenatal betamethasone and ritodrine in third trimester low risk singleton pregnancies by Doppler technology.

SUBJECTS AND METHODS

Eighty-four third trimester pregnant women who received a full course of betamethasone and delivering uneventfully were recruited. The Doppler examination included the assessment of the pulsatility index (PI) of the umbilical artery (UA PI) and the middle cerebral artery (MCA PI) prior to treatment (baseline), and 48, 72 and 96 h after the second dose of betamethasone.

RESULTS

No significant difference was found in UA PI and UA/MCA values following betamethasone therapy. In contrast, MCA PI decreased significantly 48 h from the last injection of betamethasone in the whole study group (P<0.001), and returned to basal values at 96 h. We also found that MCA PI was reduced significantly at 48 h in the subgroup under tocolysis (n=41) and in the subgroup not receiving tocolysis (n=43). We compared MCA PI values for both subgroups in the four timings, and found a non-significant difference comparing baseline and 96 h values. However, when comparing MCA PI values after 48 and 72 h, significantly lower differences in PI values in both subgroups were found.

CONCLUSION

In low risk pregnancies, betamethasone therapy in the third trimester is related to a significant but transient reduction of MCA PI, which is more pronounced during tocolytic therapy. Although the physiological basis of this effect is currently unclear, it could be related to the local regulation of intracerebral blood flow.

The Alabama preterm birth study: corticosteroids and neonatal outcomes in 23- to 32-week newborns with various markers of intrauterine infection

OBJECTIVE

Intrauterine inflammation/infection is cited as a contraindication to the use of corticosteroids (CS). Our goal was to determine if CS given prenatally to enhance fetal maturity were harmful to infants with various indications of intrauterine infection.

STUDY DESIGN

This was a retrospective analysis of data obtained from 457 consecutively enrolled infants delivered between 23 and 32 weeks. Cultures and a histologic examination of the placenta, and cord blood interleukin (IL)-6 levels were obtained. Neonatal outcomes included periventricular leukomalacia (PVL), intraventricular hemorrhage (IVH), respiratory distress syndrome (RDS), chronic lung disease (CLD), necrotizing enterocolitis (NEC), systemic inflammatory response syndrome (SIRS), and infant death.

RESULTS

Of the 457 pregnancies, 57.6% had a positive placental culture, 49.8% had histologic chorioamnionitis/funisitis, 28.8% had elevated cord IL-6 levels, and 12.5% had clinical chorioamnionitis. With intrauterine infection/inflammation, none of the neonatal outcomes were significantly worse if mothers were treated with CS. For those with histologic chorioamnionitis/funisitis, of the outcomes historically improved with CS, RDS (59.9 vs 72.2% P = .16), IVH (9.7 vs 14.7% P = .38), and neonatal death (9.9 vs 11.1% P = .82) all occurred less frequently with CS treatment, but differences were not significant. Similar results were seen for women with a positive placental culture. For women with an elevated IL-6, RDS was significantly reduced (59.4 vs 84.2 %, P = .045). Neonatal SIRS was significantly reduced with CS in women with histologic chorioamnionitis/funisitis (39.7 vs 65.7%, P = .005), positive placental cultures (32.7 vs 56.3%, P = .01), and elevated IL-6 levels (42.7 vs 73.7%, P = .02).

CONCLUSION

In women with intrauterine infection/inflammation, CS use was not associated with significant worsening in any neonatal outcome, and was associated with significant reductions in RDS and SIRS. These data suggest that CS use may not be contraindicated in the presence of intrauterine inflammation/infection.

Gestational age at preterm premature rupture of membranes: a risk factor for neonatal white matter damage

OBJECTIVE

Gestational age at delivery and spontaneous prematurity are independent risk factors for white matter damage (WMD). However, among infants delivered spontaneously after preterm premature rupture of membranes (PPROM), latency of PPROM has been inconsistently correlated with risk of WMD. We have explored whether gestational age at membrane rupture is independently associated with WMD.

STUDY DESIGN

Using a cohort of 196 liveborn singleton nonanomalous neonates born at 24.0 to 33.6 weeks from January 1993 to December 2002 after pPROM and who survived 7 days, we compared the characteristics of those who developed WMD (n = 15) with those who did not (n = 181) using Fisher exact test, Student t test, and logistic regression analysis, with a 2-tailed P < .05 or odds ratio (OR) with 95% CI not inclusive of the unity considered significant.

RESULTS

Stepwise logistic regression analysis demonstrated that gestational age at PPROM (P < .001, OR 0.79) was significantly associated with WMD. The association was independent of corticosteroid administration (P = .016), latency interval (P = .69), gestational age at delivery (P = .99), and birth weight (P = .62).

CONCLUSION

Among premature infants born at <34 weeks after pPROM, gestational age at diagnosis is independently associated with WMD.

Betamethasone effects on fetal sheep cerebral blood flow are not dependent on maturation of cerebrovascular system and pituitary-adrenal axis

Synthetic glucocorticoids are administered to pregnant women in premature labour to accelerate fetal lung maturation at a time when fetal cerebrovascular and endocrine systems are maturing. Exposure to glucocorticoids at 0.8-0.9 of gestation increases peripheral and cerebrovascular resistance (CVR) in fetal sheep. We examined whether the increase of CVR and its adverse effect on cerebral blood flow (CBF) depend on the current level of maturation of the pituitary-adrenal axis and the cerebrovascular system. Using fluorescent microspheres, regional CBF was measured in 11 brain regions before and 24 h and 48 h after the start of 3.3 microg kg(-1) h(-1) betamethasone (n = 8) or vehicle (n = 7) infusions to fetal sheep at 0.73 of gestation. Hypercapnic challenges were performed before and 24 h after the onset of betamethasone exposure to examine betamethasone effects on cerebrovascular reactivity. Betamethasone exposure decreased CBF by approximately 40% in all brain regions after 24 h of infusion (P < 0.05). The decline in CBF was mediated by a CVR increase of 111 +/- 16% in the cerebral cortex and 129 +/- 29% in subcortical regions (P < 0.05). Hypercapnic cerebral vasodilatation and associated increase in CBF were blunted (P < 0.05). Fetal CBF recovered after 48 h of betamethasone administration. There were no differences in glucocorticoid induced CBF and CVR changes compared with our previous findings at 0.87 of gestation. We conclude that the cerebrovascular effects of antenatal glucocorticoids are independent of cerebrovascular maturation and preparturient increase in activity of the fetal pituitary-adrenal axis.

Does smoking in pregnancy modify the impact of antenatal steroids on neonatal respiratory distress syndrome? Results of the Epipage study

OBJECTIVES

To assess the relation between cigarette smoking during pregnancy and neonatal respiratory distress syndrome (RDS) in very preterm birth, and to analyse the differential effect of antenatal steroids on RDS among smokers and non-smokers.

DESIGN

A population based cohort study (the French Epipage study).

SETTING

Regionally defined births in France.

METHODS

A total of 858 very preterm liveborn singletons (27-32 completed weeks of gestation) of the French Epipage study were included in this analysis. The odds ratio for RDS in relation to smoking in pregnancy was estimated using a logistic regression to control for gestational age. The odds ratio for RDS in relation to antenatal steroids was estimated taking into account an interaction between antenatal steroids and cigarette smoking, using multiple logistic regression to control for gestational age, birthweight ratio, main causes of preterm birth, mode of delivery, and sex.

RESULTS

The odds ratio for RDS in relation to smoking in pregnancy adjusted for gestational age (aOR) was 0.59 (95% confidence interval (CI) 0.44 to 0.79). The aOR for RDS in relation to antenatal steroids was 0.31 (95% CI 0.19 to 0.49) in babies born to non-smokers and 0.63 (95% CI 0.38 to 1.05) in those born to smokers; the difference was significant (p = 0.04).

CONCLUSIONS

Cigarette smoking during pregnancy is associated with a decrease in the risk of RDS in very preterm babies. Although antenatal steroids reduce the risk of RDS in babies born to both smokers and non-smokers, the reduction is smaller in those born to smokers.

Benefit of antenatal glucocorticoids according to the cause of very premature birth

In this observational study performed in a large cohort of very preterm singletons, respiratory outcome was found to be strongly dependent on the cause of premature delivery. Although less apparent in infants born to mothers with chorioamnionitis, exposure to antenatal glucocorticoids remained significantly associated with a decrease in the incidence of respiratory distress syndrome after adjustment for the main cause of premature birth.

Diagnosis and management of intrauterine growth restriction

The growth-restricted fetus is a fetus who fails to reach his growth potential and is at risk for perinatal morbidity and mortality. When a fetus has an estimated weight below the 10th percentile, in the absence of congenital anomalies and in the presence of a normal amount of amniotic fluid, Doppler velocimetry gives the most important information to differentiate the truly growth-restricted fetus from the fetus that is constitutionally small but otherwise normal. One area of debate and research is whether Doppler velocimetry can help in timing the delivery of the growth-restricted fetus. Data appear to support the use of ductus venosus velocimetry in deciding when to deliver, but randomized data on this point are still lacking.

Multiple courses of antenatal corticosteroid therapy in patients with preterm premature rupture of membranes

OBJECTIVE

This study was performed to determine the benefits and risks of multiple courses of corticosteroids in patients with preterm premature rupture of membranes (PPROM).

METHOD

We retrospectively evaluated the pregnancy and neonatal outcomes of women with singleton pregnancies, who were admitted at 24-32 weeks of gestation due to PPROM. Patients were categorized into 3 groups according to antenatal corticosteoid exposure: (1) a non-user group, (2) a single-course group, and (3) a multiple-course group.

RESULT

A total of 170 patients were included in the study, with 50 in the non-use group, 76 in the single-course group, and 44 in the multiple-course group. Univariate analyses showed that clinical chorioamnionitis occurred with highest incidence in multiple-course group (chi2=6.20, p<0.05) and the incidence of neonatal respiratory distress syndrome (RDS) was lowest in the multiple-course group (chi2=10.0, p<0.01). Multiple logistic regression analyses showed that multiple courses of corticosteroids were independently associated with clinical chorioamnionitis (odds ratio=13.15, p<0.05) whereas no significant association was found between RDS and multiple-course corticosteroids after adjusting for confounding variables (odds ratio=0.28, p=0.06).

CONCLUSION

Multiple courses of antenatal corticosteroid therapy were found to be associated with an increased risk of clinical chorioamnionitis and seemed not to reduce the incidence of RDS and other neonatal morbidities in patients with PPROM.

Antenatal corticosteroids for fetal maturation in women at risk for preterm delivery

The available data unambiguously support the beneficial, short-term fetal effects of antenatal corticosteroids in women at risk for preterm delivery. There are still several incompletely addressed questions, including the use of corticosteroids in women with preterm premature rupture of membranes, the optimal corticosteroid preparation to be used, and the impact of repeated dosing. These issues are discussed in this review from the perspective of recent scientific evidence on the mechanisms responsible for positive short-term effects on survival and possible harmful long-term effects.

Efficacy of a single dose of antenatal steroid in surfactant-treated babies under 31 weeks' gestation

OBJECTIVES

Antenatal steroids in labor improve the outcome in preterm babies. The objective in this retrospective study was to compare the efficacy of one dose of antenatal steroid against the standard course in surfactant-treated babies.

METHODS

A total of 226 babies treated with prophylactic surfactant and under 31 weeks' gestation were divided into three groups: group 1 (n = 89), no antenatal steroids; group 2 (n = 68), one dose of antenatal steroids 4-24 h before delivery; and group 3 (n = 69), two or more doses of antenatal steroids 24 h to 7 days before delivery. The three groups were compared for early clinical well-being and ultimate clinical outcome.

RESULTS

Apgar and Clinical risk index for babies (CRIB) scores in groups 2 and 3 were similar and both were significantly better than in group 1. Group 2 babies had a 23.5% reduction in serious intraventricular hemorrhage (IVH) (p < 0.0001, relative risk (RR) 0.2 (95% CI 0.07-0.54), numbers needed to treat (NNT) 4.6) and a 22.9% reduction in death (p < 0.001, RR 0.28 (95% CI 0.12-0.63), NNT 4.4) and group 3 babies had a 21.1% reduction in IVH (p < 0.001, RR 0.25 (95% CI 0.10-0.62), NNT 4.6) and a 24.2% reduction in death (p < 0.001, RR 0.23 (95% CI 0.10-0.57), NNT 4.2) compared to group 1. For these parameters, there was no significant difference between groups 2 and 3.

CONCLUSIONS

One dose of antenatal steroids given 4-24 h before delivery was clinically comparable to the recommended schedule of the National Institutes of Health in surfactant-treated preterm infants. Should the findings of this study be confirmed in randomized controlled trials, the dosage regimen could be simplified, steroid administration reduced and the interval from delivery reduced in acute clinical conditions.

Comparison of single and repeated antenatal corticosteroid therapy to prevent neonatal death and morbidity in the preterm infant

INTRODUCTION

In the case of threatened preterm delivery, repeat administration of antenatal corticosteroids is a common practice in women who have not delivered 7-14 days after the first course of corticosteroids. However, the benefits of this policy as compared to single-course administration have not been proven.

AIM

Our purpose was to compare neonatal death and morbidity after repeat antenatal courses of corticosteroids with neonatal death and morbidity after a single course.

METHODS

We performed a cohort study with matched controls. Neonates treated with repeat antenatal courses of corticosteroids were matched with neonates treated with a single course. Matching criteria were sex, single or multiple gestation, route of delivery, gestational age at delivery and year of birth. Intrauterine growth-restricted infants were matched separately. We excluded neonates with congenital malformation and neonates with an unknown number of antenatal corticosteriod courses. Outcome measures were the incidences of neonatal death, respiratory distress syndrome, intraventricular haemorrhage and necrotizing enterocolitis.

RESULTS

From the neonates treated with two or three courses of antenatal corticosteroids, 56 appropriate grown neonates and 24 intrauterine growth-restricted neonates could be matched. The incidences of neonatal death, respiratory distress syndrome, intraventricular haemorrhage and necrotizing enterocolitis did not show statistically significant differences after single and repeat courses of corticosteroids. Appropriate grown and intrauterine growth-restricted neonates showed the same results.

CONCLUSION

From our study, it can be concluded that in preterm neonates, repetition of antenatal corticosteroids seems not to improve neonatal outcome.

Maturity testing with preterm premature rupture of the membranes

The presence or absence of fetal pulmonary maturity as assessed by amniotic fluid analysis and the role of fetal maturity tests in the management of premature rupture of the membranes are addressed. The hazards of the high falsely immature test are carefully explored. A management scheme based on the results of amniotic fluid analysis is also described.

Perinatal glucocorticoid therapy and neurodevelopmental outcome: an epidemiologic perspective

A relatively brief course of antenatal glucocorticoids (ACS), given to reduce the severity of respiratory distress syndrome in preterm infants, improves survival and appears to protect against brain damage. In clinical trials as well as observational studies, ACS have been associated with a decreased risk of intraventricular haemorrhage and cerebral palsy. In observational studies a decreased risk of white-matter damage, identified with cranial ultrasound, has been observed. There is some evidence, from observational studies, that repeated courses of ACS (typically given at weekly intervals) can reduce the rate of fetal head growth, and experiments in animals provide further support for this possibility. In contrast to the effects of a brief course of ACS, postnatal glucocorticoids (PCS), given to preterm infants to reduce the severity of chronic lung disease have been associated with an increased risk of neurologic impairment. Available evidence suggests that PCS does not improve survival. Further study is needed of the neurodevelopmental consequences of both multiple courses of ACS, as well as PCS.

Effects of betamethasone administration to the fetal sheep in late gestation on fetal cerebral blood flow

Glucocorticoid administration to women at risk of preterm delivery to accelerate fetal lung maturation has become standard practice. Antenatal glucocorticoids decrease the incidence of intraventricular haemorrhage as well as accelerating fetal lung maturation. Little is known regarding side effects on fetal cerebral function. Cortisol and synthetic glucocorticoids such as betamethasone increase fetal blood pressure and femoral vascular resistance in sheep. We determined the effects of antenatal glucocorticoid administration on cerebral blood flow (CBF) in fetal sheep. Vehicle (n = 8) or betamethasone (n = 8) was infused over 48 h via the jugular vein of chronically instrumented fetal sheep at 128 days gestation (term 146 days). The betamethasone infusion rate was that previously shown to produce fetal plasma betamethasone concentrations similar to human umbilical vein concentrations during antenatal glucocorticoid therapy. Regional CBF was measured in 10 brain regions, using coloured microspheres, before and 24 and 48 h after onset of treatment, and during hypercapnic challenges performed before and 48 h after onset of betamethasone exposure. Betamethasone exposure decreased CBF in all brain regions measured except the hippocampus after 24 h of infusion (P < 0.05). The CBF decrease was most pronounced in the thalamus and hindbrain (45-50% decrease) and least pronounced in the cortical regions (35-40% decrease). It was mediated by an increase in cerebral vascular resistance (CVR, P < 0.05) and led to a decrease in oxygen delivery to subcortical and hindbrain structures of 30-40%, to 8.6 +/- 1.1 ml x (100 g)(-1) x min(-1), and 40-45 %, to 11.0 +/- 1.6 ml x 100 g(-1) x min(-1), respectively (P < 0.05). After 48 h of betamethasone treatment, the reduction in CBF was diminished to about 25-30 %, but was still significant in comparison to vehicle-treated fetuses in all brain regions except three of the five measured cortical regions (P < 0.05). CVR and oxygen delivery were unchanged in comparison to values at 24 h of treatment. The CBF increase in response to hypercapnia was diminished (P < 0.05). These observations demonstrate for the first time that glucocorticoids exert major vasoconstrictor effects on fetal CBF. This mechanism may protect the fetus against intraventricular haemorrhage both at rest and when the fetus is challenged. Betamethasone exposure decreased the hypercapnia-induced increase in CBF (P < 0.05) due to decreased cerebral vasodilatation (P < 0.05).

Risks and benefits of therapies for apnoea in premature infants

Apnoea in infants can result from a wide range of causes, and requires thorough evaluation before deciding on appropriate treatment. Continuous monitoring of premature infants with apnoea is mandatory in order to define the pathophysiology and type of apnoea; selection of treatment involves careful assessment of aetiology, as well as efficacy and tolerability in each individual case. The objective of treatment is to prevent the deleterious consequences of apnoeas that last >20 seconds and/or are associated with bradycardia, cyanosis or pallor, and occur more often than once an hour over a 12-hour period. Apnoea management involves both pharmacological and nonpharmacological treatment. We suggest methylxanthines as first-line therapy for idiopathic apnoeas; evidence suggests that caffeine is better tolerated and as efficacious as theophylline (since it is particularly efficacious against the 'central' component of idiopathic apnoea of prematurity). If treatment fails, additional measures such as doxapram may be appropriate when hypoventilation is present, or nasal continuous positive airway pressure when upper airway instability or obstructive apnoeas are predominant. Apnoea prophylaxis is an additional reason to advocate prenatal maturation with betamethasone. Weaning from treatment is attempted 4 to 5 days after complete resolution of apnoea, beginning with the last treatment introduced. Monitoring should be maintained for 4 to 5 days to detect any relapse of recurrent and severe apnoeas, which would lead to the resumption of the most recently withdrawn treatment.

The relationships between antenatal management, the cause of delivery and neonatal outcome in a large cohort of very preterm singleton infants

OBJECTIVE

To determine whether the cause of very preterm delivery influences neonatal outcome.

DESIGN

A cohort study of 685 consecutive singletons born before 33 weeks of gestation.

METHODS

Causes of birth and perinatal outcome variables were correlated for statistical significance by uni- and multi-variate analyses.

RESULTS

Intrauterine growth retardation or pre-eclampsia were associated with a higher rate of respiratory distress syndrome compared with prolonged rupture of membranes, after controlling for gestational age, antenatal corticosteroid therapy, antenatal antibiotic administration, mode of delivery and origin (inborn or outborn) (adjusted OR 3.12; 95% CI 1.55-6.28). The prevalence of grade 3-4 intraventricular haemorrhage or cystic periventricular leukomalacia was 25% in newborn babies born after intrauterine infection or prolonged rupture of membranes. Among infants born after intrauterine growth retardation/pre-eclampsia, the rate of severe intraventricular haemorrhage was 3.2% and the rate of periventricular leukomalacia was 0.9%. Compared with intrauterine infection and after controlling for potential confounding covariates, intrauterine growth retardation/pre-eclampsia was associated with a lower rate of periventricular leukomalacia (adjusted OR 0.08; 95% CI 0.02-0.41). In the same multiple logistic regression model, antenatal corticosteroid administration was associated with a lower incidence of periventricular leukomalacia (adjusted OR 0.36; 95% CI 0.16-0.79).

CONCLUSIONS

The cause of very preterm delivery has an important influence on neonatal outcome.