type of glucocorticoid(betamethasone, dexamethasone, hydro- knew the author s name, institution and the source of publication. cortisone) We resolved any disagreement until we reached consensus. Two As the case-fatalit lty rate for review authors extracted the data, checked them for discrepancies duced with advanced neonatal care, we postulated that the effect and processed them as described in Higgins 2005a. We contacted of corticosteroids may not be apparent in later trials; hence trials authors of each included trial for further information if we were analysed separately by the main decade of recruitment(if this thought this to be necessary. was not stated in trial manuscripts it was estimated using the date of first publication) For each included trial. we assessed allocation concealment There is potential for bias introduced by differential neonatal mor. using the criteria described in Section six of the Cochrane tality rates on ascertainment of intraventricular haemorrhage by Reviewers' Handbook(Higgins 2005b): adequate( autopsy versus ascertainment by ultrasound. We therefore anal- adequate(C), not used(D). We did not use studies rated ysed these two groups separately. Subgroup analysis was performed D. We collected information about blinding, and the extent to which all randomised women and their babies were accounted Prmary outcomes. for Completeness of follow up was assessed as follows: less than 5% participants excluded (A), 5% to 9.9% participants excluded SEARCH METHODS F。R (B),10%to 19.9% excluded(C), 20% or more excluded D) DENTIFICATI。N。 F STUDIES unclear(E). We excluded studies rated D. We analysed outcomes on an intention-to-treat basis. For this update, previously included See: Pregnancy and Childbirth Group methods used in reviews. studies were scrutinized again and two review authors extracted the data. We resolved discrepancies by discussion. We performed We searched the Cochrane Pregnancy and Childbirth Group statistical analysis using the Review Manager software(RevMan Trials Register(30 October 2005) 2000). In the original review, a weighted estimate of the The Cochrane Pregnancy and Childbirth Group's trials register typical treatment effect across studies was performed using the maintained by the Trials Search Co-ordinator and contains trial Peto method(i.e. the typical odds ratio: the odds of an identified from: unfavourable outcome among treatment-allocated participants to (1)quarterly searches of the Cochrane Central Register of the corresponding odds among controls). For this update, we Controlled Trials(CENTRAL) have calculated relative risks and 95% confidence intervals for (2)monthly searches of MedlinE; dichotomous data. Although odds ratios have been commonly sed in meta-analysis, there is potential for them to be inte (3)handsearches of 30 journals and the proceedings of major incorrectly and current advice is that relative risks should be used whereve (4)weekly current awareness search of a further 37 journals. Details of the search strategies for CENTRAL and MEDLINE, We limited primary analysis to prespecified outcomes. We he list of handsearched journals and conference proceedings, performed subgroup analysis for the prespecified groups. We did and the list of journals reviewed via the current awareness service not undertake any data-driven post hoc analyses. However, as the can be found in theSearch strategies for identification of studies' review progressed, it became apparent that gestational age at entry section within the editorial information about the Cochrane may be a useful category in which to study the primary outcomes Pregnancy and Childbirth Group Post hoc subgroup analysis was performed for gestational at entry Trials identified through the searching activities described above to trial(less than 26 weeks, etween 26 and 29+ 6 weeks, between are given a code(or codes)depending on the topic. The codes are linked to review topics. The Trials Search Co-ordinator and 36+6 weeks, greater than 36 weeks) for each review using these codes rather than We also found that some trials included in this review had a protocol of weekly repeat doses of corticosteroid if the mother We did not apply any language restrictions. remained undelivered. None of the trials that allowed weekly repeat doses reported outcomes separately for those exposed to repeat doses. We performed a post hoc analysis for primary METHODS OF THE REVIEW outcomes of trials where a single course was used versus those where Two review authors assessed the trials eligtbiiry and weekly repeat doses were allowed in the protocol, to determine if the inclusion of such trials biased our results. Single versus multiple methodological quality without consideration of the results. doses of corticosteroids is the subject of another review( Crowther Reasons for excluding any trial are detailed in theCharacteristics 2000). The analysis in this update will differ from that of the of excluded studies table. Trials were not assessed blind, as we single versus multiple doses review, as the latter review includes Antenatal corticosteroids for accelerating fetal lung maturation for women at risk of preterm birth( Review) Copyright @2006 The Cochrane Collaboration. Published by John wiley& Sons, Ltd• type of glucocorticoid (betamethasone, dexamethasone, hydro￾cortisone). As the case-fatality rate for respiratory distress syndrome has re￾duced with advanced neonatal care, we postulated that the effect of corticosteroids may not be apparent in later trials; hence trials wereanalysed separately by the main decade of recruitment (if this was not stated in trial manuscripts it was estimated using the date of first publication). Thereis potential for bias introduced by differential neonatal mor￾tality rates on ascertainment of intraventricular haemorrhage by autopsy versus ascertainment by ultrasound. We therefore anal￾ysed thesetwo groups separately. Subgroup analysiswas performed for primary outcomes. S E A R C H M E T H O D S F O R I D E N T I F I C A T I O N O F S T U D I E S See: Pregnancy and Childbirth Group methods used in reviews. We searched the Cochrane Pregnancy and Childbirth Group Trials Register (30 October 2005). The Cochrane Pregnancy and Childbirth Group’s trials register is maintained by the Trials Search Co-ordinator and contains trials identified from: (1) quarterly searches of the Cochrane Central Register of Controlled Trials (CENTRAL); (2) monthly searches of MEDLINE; (3) handsearches of 30 journals and the proceedings of major conferences; (4) weekly current awareness search of a further 37 journals. Details of the search strategies for CENTRAL and MEDLINE, the list of handsearched journals and conference proceedings, and the list of journals reviewed via the current awareness service can be found in the ’Search strategies for identification of studies’ section within the editorial information about the Cochrane Pregnancy and Childbirth Group. Trials identified through the searching activities described above are given a code (or codes) depending on the topic. The codes are linked to review topics. The Trials Search Co-ordinator searches the register for each review using these codes rather than keywords. We did not apply any language restrictions. M E T H O D S O F T H E R E V I E W Two review authors assessed the trials for eligibility and methodological quality without consideration of the results. Reasons for excluding any trial are detailed in the 0Characteristics of excluded studies0 table. Trials were not assessed blind, as we knew theauthor’s name, institution and thesource of publication. We resolved any disagreement until we reached consensus. Two review authors extracted the data, checked them for discrepancies and processed them as described in Higgins 2005a. We contacted authors of each included trial for further information, if we thought this to be necessary. For each included trial, we assessed allocation concealment using the criteria described in Section six of the Cochrane Reviewers’ Handbook (Higgins 2005b): adequate (A), unclear (B), inadequate (C), not used (D). We did not use studies rated D. We collected information about blinding, and the extent to which all randomised women and their babies were accounted for. Completeness of follow up was assessed as follows: less than 5% participants excluded (A), 5% to 9.9% participants excluded (B), 10% to 19.9% excluded (C), 20% or more excluded (D), unclear (E). We excluded studies rated D. We analysed outcomes on an intention-to-treat basis. For this update, previously included studies were scrutinized again and two review authors extracted the data. We resolved discrepancies by discussion. We performed statistical analysis using the Review Manager software (RevMan 2000). In the original review, a weighted estimate of the typical treatment effect across studies was performed using the ’Peto method’ (i.e. ’the typical odds ratio’: the odds of an unfavourable outcome among treatment-allocated participants to the corresponding odds among controls). For this update, we have calculated relative risks and 95% confidence intervals for dichotomous data. Although odds ratios have been commonly used in meta-analysis, there is potential for them to be interpreted incorrectly and current advice is that relative risks should be used wherever possible (Higgins 2005a). We limited primary analysis to prespecified outcomes. We performed subgroup analysis for the prespecified groups. We did not undertake any data-driven post hoc analyses. However, as the review progressed, it became apparent that gestational age at entry may be a useful category in which to study the primary outcomes. Post hoc subgroup analysis was performed for gestational at entry to trial (less than 26 weeks, between 26 and 29 + 6 weeks, between 30 and 32 + 6 weeks, between 33 and 34 + 6 weeks, between 35 and 36 + 6 weeks, greater than 36 weeks). We also found that some trials included in this review had a protocol of weekly repeat doses of corticosteroid if the mother remained undelivered. None of the trials that allowed weekly repeat doses reported outcomes separately for those exposed to repeat doses. We performed a post hoc analysis for primary outcomes oftrialswhereasinglecoursewas used versusthosewhere weekly repeat doses were allowed in the protocol, to determine if theinclusion of such trials biased ourresults. Single versus multiple doses of corticosteroids is the subject of another review (Crowther 2000). The analysis in this update will differ from that of the single versus multiple doses review, as the latter review includes Antenatal corticosteroids for accelerating fetal lung maturation for women at risk of preterm birth (Review) 6 Copyright © 2006 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd 第 100 页