Homocysteine levels are unaffected by metformin treatment in both nonpregnant and pregnant women with polycystic ovary syndrome

Background. Women with polycystic ovary syndrome have elevated homocysteine levels. Elevated homocysteine levels associate with pregnancy complications. Women with polycystic ovary syndrome are often treated with metformin, a drug that may increase homocysteine levels. Hence, we investigated the effect of metformin treatment on homocysteine levels in nonpregnant and pregnant women with polycystic ovary syndrome. Methods. Two prospective randomized placebo-controlled studies included women with polycystic ovary syndrome in a university hospital setting. Sixty-three infertile women were treated with metformin 1,000 mg bid or placebo for 16 weeks and 38 pregnant women with metformin 850 mg bid or placebo from the first trimester and throughout pregnancy. All the women had polycystic ovary syndrome and all participants received diet and lifestyle advice, and oral folate and vitamin B12 substitution, and a daily oral multivitamin tablet. The main outcome measures were serum levels of homocysteine, folate, and vitamin B12. Results. Serum homocysteine levels were unaffected by metformin treatment both in nonpregnant and pregnant women with polycystic ovary syndrome. However, in nonpregnant women both serum folate and vitamin B12 levels decreased with treatment. At inclusion in nonpregnant women, serum homocysteine levels associated negatively with serum levels of folate and methyl malonic acid and positively with free testosterone index. No such associations were seen in pregnant women. Conclusions. Metformin treatment in women with polycystic ovary does not increase serum homocysteine levels in the nonpregnant or the pregnant state.