ORs and 95% CIs were used for case–control studies and adjusted analyses. Outcomes that were sufficiently similar across studies, and reasonable resistant to biases and relatively homogeneous in this respect, were aggregated in meta-analyses. When Imatinib molecular weight available, we pooled adjusted estimates; otherwise, we pooled the unadjusted estimates based on crude data from the individual
studies. ORs and RRs greater than one indicate an increased risk of complications with FGM/C; if less than one, they indicate a decreased risk. We anticipated heterogeneity between studies due to different study methodologies and geographical and population differences. Heterogeneity was examined using the χ2 test and I2 statistic. We used a random-effects model to account for within-study and between-study heterogeneity. In random-effects meta-analysis, the weight assigned to each included study is adjusted to include a measure of variation (τ2) in the effects reported between studies. We used the Mantel-Haenszel method
for unadjusted dichotomous data, and for adjusted data we used the generic inverse-variance method, in which weight is given to each study according to the inverse of the variance of the effect, to minimise uncertainty about the pooled effect estimates. Analyses were done with Review Manager (V.5.2.8). We applied the instrument Grading of Recommendations Assessment, Development and Evaluation (GRADE) to assess the extent to which we have confidence in the effect estimates.17 GRADE is a transparent and systematic approach to grading our confidence in the evidence. For resource reasons, we used GRADE only for outcomes eligible for meta-analysis. Those of us who did the systematic review were not masked to the authors, institution or journal of publication. The use of non-masked reviewers is accepted practice in meta-analyses and
has been shown not to bias results.18 In line with recommendations,14 results from the studies deemed to have the highest internal validity were given preference. In this communication, we present all studies that reported outcomes for differentially FGM/C exposed groups of women, that is, studies with a comparison group. Role of the funding source Norad and the WHO commissioned the study and the latter Batimastat contributed some funding ($10 000). The commissioners of the systematic review had no role in the study design, data collection, data analysis, data interpretation or writing of the report. RCB had final responsibility for the decision to submit for publication. Results Our search strategy identified 5109 unique publications, the titles and abstracts of which were screened for inclusion. The full text of 12 publications could not be located, while 431 articles were retrieved, of which 185 met the inclusion criteria (figure 2). Figure 2 PRISMA flow diagram for selection of literature.