In this view, the present meta-analysis was unable to confirm the association between IL−1B (−511) polymorphism and the risk of PID, and this zero association was already observed elsewhere [16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37]. This evidence concerns the gene IL1B and pelvic inflammatory disease.