Of these trials, four compared DPP-4 inhibitors against placebo (SAVOR-TIMI 53, EXAMINE, TECOS, CARMELINA), eight compared GLP-1RA against placebo (ELIXA, LEADER, SUSTAIN-6, EXSCEL, HARMONY, REWIND, PIONEER 6, AMPLITUTE-O) and eleven compared SGLT-2 inhibitors against placebo (EMPA-REG, CANVAS, DECLARE, CREDENCE, DAPA-HF, DAPA CKD, VERTIS-CV, EMPEROR-R, SCORED, SOLOIST-WHF, EMPEROR-P). This evidence concerns the gene DPP4 and hydrops fetalis.