INS and Insulin resistance: A meta-analysis of 17 studies (both RCT and non-RCT) with 2,899 participants demonstrated reduced incidence of early miscarriage, preterm delivery, preeclampsia, GD, the need for insulin treatment and maternal weight gain.58 Another meta-analysis of 11 RCTs found that metformin does not lower the risk of GD in high-risk individuals with obesity, PCOS or pre-existing insulin resistance.59 Another meta-analysis of six RCTs involving 1,229 participants showed benefit only in the risk of preterm delivery but did not affect the incidence of GD, miscarriage, preeclampsia and birthweight.60