A prospective, partially randomized study of pregnancy outcomes and hematologic responses to oral and intramuscular iron treatment in moderately anemic pregnant women.

Background: Daily oral iron supplementation during pregnancy fails to reduce the prevalence of anemia. However, 2 or 3 intramuscular doses of iron given at monthly intervals were recently found to be effective.

Objective: We compared the safety and efficacy in treating pregnancy anemia of 3 intramuscular doses of iron given at monthly intervals with those of daily oral iron supplementation.

Design: In a prospective, partially randomized study, 148 pregnant women received daily oral doses of 100 mg elemental Fe and 500 micro g folic acid, and 106 pregnant women received 3 intramuscular doses of 250 mg elemental Fe as iron dextran at 1-mo intervals and oral doses of 5 mg folic acid twice weekly. One hundred women in each group completed the study. Changes in hemoglobin, iron indicators, pregnancy outcomes, and birth weight were compared between the 2 groups.

Results: Hemoglobin and iron indicators improved significantly with both treatments. The increase in serum ferritin concentration after parenteral iron treatment was significantly higher than that after oral iron treatment. No significant differences between the 2 groups in pregnancy outcomes and birth weight were observed. Systemic side effects were more common in the parenteral iron group, whereas gastrointestinal side effects were more common in the oral iron group.

Conclusions: The intramuscular administration of 3 doses of 250 mg Fe at monthly intervals appears to have good compliance and efficacy and may be used in women who cannot tolerate oral administration of iron. However, intramuscular administration of iron is appropriate only in hospital settings well equipped to treat anaphylactic crises.