Hello! Thanks for posting your query. It is better to continue metformin during pregnancy for a women with PCOS. There are many advantages and disadvantages of taking metformin during pregnancy. Administration of metformin throughout pregnancy to women with PCOS was associated with a marked and significant reduction in the rate of early pregnancy loss. A smaller prospective pilot study19 in 19 women with PCOS demonstrated a 63% decrease in spontaneous abortions in women treated with metformin. A prospective observational study of 42 pregnancies in 39 women with PCOS that was published in 2004 demonstrated the effectiveness of metformin in reducing the incidence of gestational diabetes mellitus in this high-risk population. Study results are as:- Metformin therapy during conception and continued during pregnancy in 72 oligo/amenorrheic women with PCOS was safely associated with reduction in spontaneous abortion (17% with metformin vs. 62% without) and in GDM (4% with metformin vs. 26% without), was not teratogenic, and did not adversely affect birth weight or height, weight, and motor and social development at 3 and 6 months of life.There was no maternal lactic acidosis, no maternal or neonatal hypoglycemia, and no congenital malformation in live births. The question of whether to use metformin in the treatment of PCOS remains a hotly debated subject.Benefits overweight than side effects hence better to continue metformin during pregnency with PCOS. Consult with the endocrinologist regarding management of PCOS and clinical correlation. Hope this helps you. Wish you good health.