Is it safe to take metformin for pcos while breastfeeding my 8 month old?

It is safe/increases: All evidence shows that taking metformin and brest feeding is safe.It can also increase the production of milk with mothers with pcos.

Yes.: Only 0.28% of the weight-normalized maternal dose of metformin enters human breast milk. In rodents, the metformin concentration in milk approaches that of the maternal plasma. This is well below the 10% level usually expected for the concentration to have a clinical impact. Please do not attempt another pregnancy until the first birthday of your little one, though. Take Folic Acid 1-5 mg daily!