Women often do not meet the increased iron and folate needs of pregnancy. Maternal iron-deficiency anemia is associated with poor,maternal and infant outcomes, including preterm delivery and low birth weight. Poor folate status increases risk for maternal anemia. spontaneous abortion, and congenital defects. Because of I pregnancy. There are few data on iron, and folate this, supplemental iron and folate are often recommended during status in pregnant women in Switzerland. We measured iron and folate status in a national sample of Swiss pregnant. women, estimated the prevalence of anemia, and determined if supplement use is associated with iron and/or,, folate status in this group. A 3-stage probability to size cluster sampling method was used to obtain a representative national sample Of pregnant women (n = 381) in the second and third trimester. We measured hemoglobin, hematocrit, mean corpuscular volume, and serum folate and ferritin concentrations. Serum transferrin receptor concentration was determined in anemic subjects. The use of iron and folate supplements, was evaluated by questionnaire. Mean hemoglobin (+/- SD) in the sample was 123 g/L (+/- 1.0). The prevalence of anemia was 6%. Of the 21 anemic women, I I were iron-deficient, giving an iron-deficiency anemia pre I valence of 3%. Nineteen percent n of women bad low serum ferritin concentrations (< 12 mug/L) and 4% had low serum folate concentrations (< 2.5 mug/L). Supplements containing iron were taken by 65% of women, and 63% were taking folate-containing ing supplements. Womemin the second and third trimester takin containing supplements had signi-ficant, higher serum folate concentrations compared to those not taking a folate supplement (p < 0.001). In the third tia trimester, women taking iron-containing supplements had significantly higher serum. ferritin concentrations compared pared to those not taking an iron-containing supplement (p < 0.01). Our findings indicate that iron and folate status appears to be adequate in the majority of pregnant women im Switzerland, and that use of iron and. folate supplements, may have a positive impact on status.