Compared with intravenous saline alone, except for nitroglycerin (odds ratio [OR]: 1.02, 95% CI [0.36–2.88]), the other drugs significantly reduced the CIN incidence with OR of 0.35 (95% CI [0.24–0.51]) for BNP, 0.52 (0.29, 0.94) for usual-dose nicorandil, 0.28 (0.19, 0.43) for double-dose nicorandil. This evidence concerns the gene NPPB and cervical squamous intraepithelial neoplasia.