[Effect of iron supplementation and its frequency during pregnancy].

The iron (Fe) nutritional status of 203 healthy pregnant women was assessed at the first prenatal visit (To) (gestational age: 16.9 weeks +/- 3.81. Women were randomly assigned to one of three groups: G1 and G2 were supplemented with ferrous fumarate (60 mg elemental Fe) daily or intermittently (three times a week), respectively; and GC was the control group, without supplementation. The follow up was carried out until 34-37 weeks of gestational age (Tf), but only 43% of pregnant women completed the trial. At To and Tf fasting blood samples were collected and Hematocrit (Hct), Hemoglobin (Hb), Erythrocyte Protoporphyrin (EP) and Serum Ferritin (FERR) were determined. The percentage of women with abnormal biochemical values at To (n = 203) was: Hb (g/dl) < 10.5: 2.6%; PE (microgram/dl of red blood cells) > 70: 4.8%; FERR (ng/ml) < 10: 4.4%. Results (X +/- DE) of women that completed the follow up were at To and Tf, respectively: Hct (%): GC: 37.7 +/- 3.4 and 36.0 +/- 3.2 (p < 0.05); G1: 38.8 +/- 2.2 and 38.0 +/- 2.6; G2: 39.0 +/- 2.7 and 37.7 +/- 3.7; Hb (g/dl): GC: 12.5 +/- 1.2 and 11.9 +/- 1.3 (p < 0.05); G1: 12.6 +/- 1.1 and 12.8 +/- 1.1; G2: 12.9 +/- 0.9 and 12.2 +/- 1.5; PE (microgram/dl red blood cells): GC: 30 +/- 17 and 43 +/- 22 (p < 0.01); G1: 26 +/- 13 and 38 +/- 21 (p < 0.01); G2: 26 +/- 16 and 31 +/- 26; FERR (ng/ml): GC: 75 +/- 67 and 31 +/- 49 (p < 0.01); G1: 46 +/- 34 and 19 +/- 10 (p < 0.01); G2: 43 +/- 11 and 11 +/- 7 (p < 0.01). These results show: a) Fe administration was efficient to mitigate Hb decrease; b) Fe stores decreased during pregnancy regardless of Fe supplementation and frequency; c) EP values indicate that intermittent Fe administration was more efficient to maintain normal erythropoiesis.