Objective: To investigate the iron status of women at term and its impact in their neonates. Study design: Serum ferritin (SF) was measured in 201 women at term and in their newborns. The relationship between maternal and infant SF and hemoglobin (Hb) and the effects of partial prenatal care and iron supplementation were analyzed. Results: 86% of the women had iron deficiency (ID) at term and 46% were anemic. 13 (7.5%) of the babies born to the 172 iron deficient mothers were also iron deficient, but none of the babies born to the 29 mothers with SF levels > 12 &mgr;g/L. The mean cord ferritin level (103.6 +/- 75 &mgr;g/L) and Hb (164 +/- 20 g/L) were significantly higher in babies born to mothers who had SF > 12 &mgr;g/L, compared to babies born to iron deficient mothers (73.5 +/- 49 &mgr;g/L and 156 +/- 16 g/L). The respective values in iron deficient babies were 7.1 +/- 3.5 &mgr;g/L and 157 +/- 9.0 g/L, compared to 82.8 +/- 52.8 &mgr;g/L and 162 +/- 17.5 g/L in the iron sufficient babies. Conclusion: ID was diagnosed in 86% of women at term and in 7.5% of their neonates. A placental iron threshold, limiting iron acquiscition by the fetuses of women with severe ID, is suggested.