What are the indications and guidelines for intravenous (IV) iron infusions in pregnant women?

From the Guidelines

Iron infusions are recommended for pregnant women with iron deficiency anemia who cannot tolerate oral iron supplements or have not responded adequately to them. The most commonly used preparations include iron sucrose (Venofer), ferric carboxymaltose (Ferinject/Injectafer), and low molecular weight iron dextran (Cosmofer/INFeD) 1. Typical dosing for iron sucrose is 200-300mg per infusion given over 30 minutes, repeated 2-3 times weekly until the calculated total iron deficit is met. Ferric carboxymaltose allows for higher single doses (up to 1000mg) administered over 15 minutes, often requiring fewer infusions. Treatment should ideally occur in the second or third trimester when organogenesis is complete, though severe anemia may warrant earlier intervention. Iron infusions help rapidly restore iron stores, increase hemoglobin levels, and reduce risks associated with maternal anemia including preterm birth, low birth weight, and postpartum hemorrhage complications. Patients should be monitored for potential side effects including hypotension, nausea, headache, and rarely anaphylaxis, with appropriate emergency medications available during administration. Follow-up blood tests are recommended 2-3 weeks after infusion to assess response, with hemoglobin levels expected to rise by approximately 1g/dL within this timeframe.

Some key points to consider:

• The usual dose of elemental iron per day is 60 to 120 mg for pregnant women with iron deficiency anemia 1.
• Prenatal vitamins often include a low dose of iron, with the usual dose prescribed in early pregnancy being 30 mg of elemental iron per day 1.
• The Recommended Dietary Allowance for iron in pregnant women is 27 mg per day, with natural food sources of iron including certain fruits, vegetables, meat, and poultry 1.
• Iron infusions can help reduce the risks associated with maternal anemia, including preterm birth, low birth weight, and postpartum hemorrhage complications 1.
• Patients should be monitored for potential side effects, and follow-up blood tests are recommended to assess response to treatment 1.

The evidence suggests that iron infusions are a safe and effective treatment for pregnant women with iron deficiency anemia who cannot tolerate oral iron supplements or have not responded adequately to them 1.

From the FDA Drug Label

Published studies on intravenous iron sucrose treatment after the first trimester of pregnancy have not shown adverse maternal or fetal outcomes Available reports of intravenous iron sucrose use in pregnant women during the first trimester are insufficient to assess the risk of major birth defects and miscarriage There are risks to the mother and fetus associated with untreated IDA in pregnancy as well as risks to the fetus associated with maternal severe hypersensitivity reactions Iron deficiency anemia during pregnancy should be treated. Untreated IDA in pregnancy is associated with adverse maternal outcomes such as post-partum anemia Adverse pregnancy outcomes associated with IDA include increased risk for preterm delivery and low birth weight

Iron infusions in pregnancy can be considered after the first trimester, as published studies have not shown adverse maternal or fetal outcomes 2. However, available reports are insufficient to assess the risk of major birth defects and miscarriage during the first trimester.

• Untreated IDA in pregnancy is associated with adverse maternal and fetal outcomes, including post-partum anemia, preterm delivery, and low birth weight.
• Severe hypersensitivity reactions can occur in pregnant women with parenteral iron products, which may cause fetal bradycardia. It is essential to weigh the risks and benefits of iron infusions in pregnancy, considering the potential risks of untreated IDA and the limited data on the use of iron sucrose during the first trimester.

From the Research

Iron Infusions in Pregnancy

• Iron infusions are used to treat iron deficiency anemia in pregnant women, with studies showing their effectiveness in rapidly replenishing iron stores and correcting anemia 3, 4.
• A meta-analysis found that intravenous iron is superior to oral iron for treating iron-deficiency anemia in pregnancy, with benefits including achieving target hemoglobin levels more often, increasing hemoglobin levels after 4 weeks, and decreasing adverse reactions 4.
• Different iron formulations can be used for intravenous infusions, including ferric carboxymaltose, iron dextran, and iron sucrose, each with its own risks and benefits 5, 6.
• The risk of severe infusion reactions is associated with all iron preparations, but modern formulations have improved safety profiles, with the risk of moderate to severe infusion reactions affecting less than 1% of patients 5.
• Ferric carboxymaltose, in particular, has been shown to be an effective and generally well-tolerated treatment for iron deficiency anemia in pregnant women, although it may be associated with hypophosphatemia and other biochemical changes 3, 5.
• A comparison of the safety of different iron formulations, including ferric derisomaltose, iron sucrose, and ferric carboxymaltose, found that ferric derisomaltose had a lower risk of serious or severe hypersensitivity reactions 6.
• It is essential to note that one of the provided studies is not relevant to the topic of iron infusions in pregnancy, as it discusses a factor from enteric bacteria amplifying the induction of liver enzyme by glucocorticoid 7.