I was trying to do meta analysis o effect of ART on congenital anomalies. I was trying to do subgroup analysis. I am getting data for subgroups (ART, PI, NRTI, NNRTI) from one study. Can I take and put them together in Rev man. When i didthe author may appear 2 times in the pooled analysis. Did any one has information how to inter this type of data in Revman or Stata.