Background: Women with polycystic ovarian syndrome (PCOS) often have insulin resistance and hyperinsulinaemia and may therefore be at an increased risk for gestational diabetes mellitus (GDM). Metformin is widely prescribed to pregnant women with PCOS in an attempt to reduce pregnancy complications. Metformin is not approved for this indication, and evidence for this practice is lacking Aim: the objective of this study was to compare the pregnancy outcomes if metformin was continued till delivery in pregnant PCOS patientsto the outcomes if metformin was discontinued at 12 weeks. Materials and methods: this single institution study included 81 women diagnosed with PCOS who conceived with metformin and randomised into two groups, group 1 who continues metformin till delivery and group 2 who discontinued metformin at 12 weeks. Obstetrical outcomes measured were GDM, Gestational hypertension, fetal growth restriction (FGR) and preterm delivery. Results: Gestational hypertension was seen in 25% in group 1 and 33 % in group 2. 20% patients were found to have GDM in group 1 and 33% in group 2..Preterm labour rate in group 1 and group 2 were 25% and 33% respectively. Incidence of FGR was similar in both groups, 18%. Conclusion: Metformin appeared to reduce the incidence of GDM, especially need for insulin initiation if taken throughout pregnancy. It also appeared to reduce the incidence of hypertensive complications and preterm labour in this study. Metformin appeared to have no correlation to fetal growth restriction as evidenced by this study.