Maternal iron deficiency anemia (IDA) is associated with risk of adverse perinatal outcomes. Oral iron is recommended to reverse anemia, but has gastrointestinal toxicity and frequent non-adherence. Intravenous (IV) iron is reserved for intolerance of, or unresponsiveness to, oral therapy, malabsorption, and severe anemia (1% with hemoglobin [Hgb] levels <7 g/dL). With rare (<100 per one million) adverse events (AEs) ability to infuse a sufficient dose of low molecular weight iron dextran (LMWID) over 60 min, LMWID is an attractive option. This study demonstrated safety and efficacy of rapid IV infusion of 1,000 mg LMWID to gravidas with moderate to severe IDA. An observational treatment study of 1,000 mg LMWID administered over 1 hr for IDA in 189 consecutive, unselected second and third trimester gravidas after oral iron failure was conducted. All received a test dose of 25 mg LMWID and were monitored for AEs during the 60-min infusion. No premedication was administered unless more than one drug allergy or asthma was present in which case IV methylprednisolone was administered. All were followed through pregnancy and delivery. Monitored parameters included Hgb, mean corpuscular volume, serum ferritin, and percent transferrin saturation. About 189 subjects received 1,000 mg LMWID. No serious AEs occurred. About 2% experienced transient infusion reactions. Hgb improved by 1-1.9 g/dL in 82% and ≥2 g/dL in 24%. Second trimester treatment was not associated with greater Hgb improvement than third trimester treatment. Anemia resolved in 95%. Administration of a single large dose of IV LMWID was effective, safe, and convenient. Am. J. Hematol. 91:590-593, 2016. © 2016 Wiley Periodicals, Inc.