Syed et al. BMC Public Health 2011, 11(Suppl 3):S2 http://www.biomedcentral.com/1471-2458/11/S3/S2 Data abstraction The data were extracted by two researchers into a stan- dard Web excel sheet prepared by the CHERG/LiST review group [8]. The variables considered included, for example, location of the study, setting, study design, blinding assessment, allocation concealment, intention- to-treat analysis, lost to follow-up rates, intervention and control group definitions and study limitations. Study characteristics and quantitative data synthesis The study designs considered were randomized, quasi- randomized trials and observational studies. We generated meta-analyses using RevMan 5.0 software for outcomes where more than one study was available [9]. The assessment of statistical heterogeneity among trials was done by visual inspection i.e. the overlap of the con- fidence intervals among the studies, and by the Chi square (P-value) of heterogeneity in the meta-analyses. A low P value (less than 0.10) or a large chi-squared sta- tistic relative to its degree of freedom was considered as providing evidence of heterogeneity. The I2 values were also looked into, and an I2 value greater than 50% was taken to represent substantial and high heterogeneity. In situations of substantial or high heterogeneity being pre- sent, causes were explored, sub-group analyses per- formed and random effects model was used; and although, this random model is not a substitute for a thorough investigation of heterogeneity, it was primarily to take into account heterogeneity that could not be explained. Summary estimates were presented as relative risk with 95% confidence interval. For cluster randomized trials, the cluster-adjusted values were used if reported in the studies themselves. We also applied the CHERG adaptation of the GRADE criteria to grade the evidence presented by the studies in our meta-analyses [8,10]. The Child Health Epidemiology Reference Group (CHERG) guidelines are applied by scientists conducting reviews of intervention effects for use in The Lives Saved Tool (LiST). The six steps in the CHERG inter- vention review process include: (i) defining the scope of the review; (ii) conducting the literature search; (iii) extracting information from individual studies; (iv) assessing and summarizing the evidence; (v) translating the evidence into estimates of intervention effects and (vi) presenting the results. The Lives Saved Tool (LiST) uses estimates of the effects of interventions on cause-specific child mortality as a basis for generating projections of child lives that could be saved by increasing coverage of effective inter- ventions. Estimates of intervention effects are an essen- tial element of LiST, and need to reflect the best available scientific evidence [8]. Page 3 of 12 The World Bank list of economies (July 2009) [11] was used to classify countries into developing and devel- oped. Low- and middle-income countries were taken as developing, while high income countries were taken as developed. Delphi process for establishing expert consensus For the intervention of diabetes screening and manage- ment, in general, during pregnancy, we also sought expert consensus via the Delphi method. The Delphi technique (subsequently referred to as the Delphi) uses a series of sequential questionnaires or ‘rounds’, inter- spersed by controlled feedback, that seek to gain the most reliable consensus of opinion among a group of experts. It is a technique that is useful for situations where individual judgments must be tapped and com- bined in order to address a lack of agreement or incom- plete state of knowledge. As such, the Delphi is particularly valued for its ability to structure and orga- nize group communication [12]. The panel invited to participate were experts in maternal health representing six WHO regions (South Asia, Africa, Western Europe, Eastern Europe, North America, Australia), and includ- ing multiple disciplines - international health, obstetrics/ gynecology, midwifery, etc. Thirty-one experts agreed to participate in the Delphi process. The questionnaire was developed by MYY and ZAB, and refined after several rounds of pilot testing. The questionnaire was sent by email. It included the background and aims of the Del- phi and estimates of effect that were available from the literature for different scenarios. The median response and range were determined for each question. Consen- sus was defined a priori as an inter-quartile range in responses of not more than 30% for each question. For those estimates not reaching consensus, the plan was for results to be electronically distributed to the panel, vir- tual discussion allowed, and a second round of email questionnaires sent. However, consensus was achieved after one round of questionnaires and subsequent rounds were not necessary. Results The above mentioned search strategy yielded 2162 hits that were reviewed and 261 abstracts of interest were preliminarily selected. After careful review of these stu- dies, 70 studies were reviewed in detail. A flow diagram detailing the study abstraction process is given below (figure 1). Our search yielded 14 intervention studies [13-25] and 56 observational studies [16,26-80]. The stu- dies included in review articles, which were not in our short-listed articles, were added as hand searched from bibliography. In depth characteristics of these studies are presented in Additional File 1.