[Hemoglobin values for pregnant women residing at middle altitude]. / Valores de hemoglobina en mujeres embarazadas residentes en zonas de altitud media.

OBJECTIVE: To determine maternal hemoglobin behavior during pregnancy for middle altitude residents and to compare it with that reported in other populations with or without iron supplementation. MATERIALS AND METHODS: Hematological values from 227 pregnant women residing at 2 240 m altitude (Mexico City), with low obstetric and perinatal risk, and receiving supplementary iron, were compared with reference values obtained from other populations of pregnant women residing at different altitudes, after correcting for altitude. RESULTS: While the hemoglobin values for the first and second trimester of pregnancy in our studied population were similar to those reported for iron-supplemented populations (p>0.05), the third trimester values were similar to those reported for a population without this supplement (p>0.05). CONCLUSIONS: Despite receiving supplementary iron, hemoglobin values during pregnancy from women residing at middle altitude show similar behavior to that reported for pregnant women without iron supplementation.